Orthopaedics & MSK — MCQs

Q: A 45-year-old man presents with acute severe lower back pain and leg weakness. MRI shows large central disc herniation with cauda equina compression. What is the surgical urgency?

Emergency (hours). ***Emergency (hours)***- **Cauda Equina Syndrome (CES)** caused by acute central disc herniation requires immediate surgical decompression, ideally within **6 to 24 hours**, to maximize the chances of recovering full **neurological function**.- Delaying intervention significantly increases the risk of permanent disabling deficits, particularly **bladder and bowel incontinence** and **irreversible muscle weakness**.*Elective (weeks)*- Elective scheduling is appropriate only for stable conditions or those where chronic pain management is the primary goal, not for acute **nerve root compression syndromes**.- Delaying care by weeks in a confirmed CES case guarantees a poor prognosis regarding **sphincter and motor function**.*Urgent (days)*- While CES is highly urgent, characterizing it over *days* risks missing the critical window for decompression; the condition deteriorates rapidly.- Intervention for CES must be initiated immediately upon diagnosis (within **hours**), differentiating it from conditions that can safely wait 24–72 hours.*No surgery needed*- A mass lesion (large central disc herniation) causing acute **cauda equina compression** will not resolve adequately through conservative management alone.- Surgery is necessary to mechanically relieve the pressure on the nerve roots and prevent **permanent paralysis and sensory loss**.*Depends on symptoms*- The provided clinical presentation (acute severe low back pain and **leg weakness**) already suggests significant neurological compromise.- The combination of symptoms and the confirmed **cauda equina compression** on MRI elevates this to a non-negotiable surgical emergency, regardless of the precise degree of **sphincter dysfunction** at presentation.

Q: A 24-year-old man presents with acute onset severe lower back pain and bilateral leg weakness. He has urinary retention and saddle anesthesia. What is the time frame for surgical intervention?

Within 24-48 hours. ***Within 24–48 hours*** - This clinical presentation (severe low back pain, bilateral weakness, urinary retention, and **saddle anesthesia**) defines **Cauda Equina Syndrome (CES)**, a true neurosurgical emergency. - Urgent **surgical decompression** performed within the **24–48 hour** window is critical to maximize the likelihood of recovery, especially of fragile **bladder and bowel function**. *Within 6 hours* - While immediate intervention is ideal and preferred, **6 hours** is often an unfeasible or highly strict cutoff given the variability in symptom presentation and necessary preparatory steps (MRI, planning). - The key critical window recognized for achieving maximal recovery after diagnosis of **CES** spans up to 48 hours. *Within 1 week* - Delaying surgical decompression past the 48-hour mark dramatically increases the risk of **irreversible neurological injury**, particularly to the **sacral roots** controlling continence. - This timeframe is too slow for an acute compressive syndrome that leads to potential permanent **paralysis** and disability. *Within 1 month* - A delay of one month ensures **permanent neurological deficits**, including irreversible loss of motor function and **bladder/bowel control**. - This time frame is irrelevant to the management of an acute, progressive **cauda equina compression**. *No time limit* - **Cauda Equina Syndrome** is an urgent condition where prolonged compression results in direct **ischemic injury** and necrosis of the spinal nerve roots. - Lack of timely decompression guarantees poor long-term outcome and **permanent functional disability**, thus a time limit is essential.

Q: A 72-year-old man presents with confusion and agitation 3 days after hip surgery. He sees people who aren't there and is disoriented to time and place. What is the most likely diagnosis?

Postoperative delirium. ***Postoperative delirium*** - This diagnosis perfectly fits the clinical picture: an acute onset of confusion, agitation, and **visual hallucinations** (seeing people who aren't there) in an elderly patient following a major stressor like hip surgery. - Delirium is an **acute, fluctuating disturbance** of attention and cognition, and advanced age combined with recent surgery is the most common risk factor for the postoperative subtype.*Dementia* - Dementia is characterized by a **chronic, progressive decline** in memory and other cognitive domains, which is inconsistent with the acute change observed over 3 days. - While individuals with pre-existing dementia are at high risk for delirium, the acute change itself is defined as **superimposed delirium**, not just dementia.*Alcohol withdrawal* - This diagnosis (especially **delirium tremens**) can cause agitation and prominent visual or tactile hallucinations, but it requires a history of **heavy chronic alcohol use** which is not specified. - Symptoms typically peak 48–96 hours after cessation, and while the timing is plausible, the recent major surgery provides a more direct and common cause for the observed presentation in the absence of a known history of substance abuse.*Depression* - Depression presents with mood disturbances, anhedonia, and vegetative symptoms, but it does **not cause acute, global disorientation** or **frank visual hallucinations**. - Although severe depression can cause cognitive slowing (**pseudodementia**), it lacks the acute-onset, hyperactive agitated state frequently seen in delirium.*Anxiety* - Anxiety is characterized by excessive worry, tension, and autonomic symptoms, but it does **not cause acute disorientation** to time and place or complex **visual hallucinations**. - The patient's confusion and disorientation indicate a global disturbance of cortical function, which is not characteristic of primary anxiety disorders.

Q: A 25-year-old man presents with acute onset severe lower back pain radiating down his left leg to the foot. He has difficulty walking and reports numbness in his left foot. Straight leg raise test is positive at 30 degrees. What is the most likely diagnosis?

Lumbar disc herniation. ***Lumbar disc herniation*** - The presentation of **acute onset severe lower back pain** radiating down the left leg to the foot, along with **numbness in the left foot** and difficulty walking, are classic signs of nerve root compression. - A **positive straight leg raise test at 30 degrees** is a strong indicator of nerve root irritation, highly suggestive of lumbar disc herniation. *Mechanical back pain* - **Mechanical back pain** is typically localized axial pain, aggravated by movement, and **does not cause radicular symptoms** or objective neurological deficits such as foot numbness or weakness. - This diagnosis would not explain the **positive straight leg raise test** or the specific neurological symptoms in the left leg and foot. *Spinal stenosis* - **Spinal stenosis** usually affects older patients, presenting with **neurogenic claudication** (leg pain relieved by sitting or forward flexion) rather than acute, severe unilateral radiculopathy in a 25-year-old. - The onset is typically insidious and chronic, not acute, and it often involves bilateral leg symptoms. *Cauda equina syndrome* - **Cauda equina syndrome** is a serious emergency characterized by **saddle anesthesia**, **bowel or bladder dysfunction** (e.g., urinary retention), and often bilateral leg weakness, none of which are reported here. - While it can cause severe lower back pain and leg symptoms, the absence of these hallmark

Q: A 45-year-old man presents with acute severe lower back pain after lifting heavy weights. He has bilateral leg weakness, saddle anesthesia, and urinary retention. What is the most appropriate immediate management?

Emergency surgical decompression. ***Emergency surgical decompression***- This clinical presentation (saddle anesthesia, bilateral weakness, urinary retention following heavy lifting) is diagnostic of **Cauda Equina Syndrome (CES)**.- **Emergency surgical decompression**, ideally within 24–48 hours of symptom onset, is mandatory to preserve neurological function and optimize recovery of **bladder/bowel control**.*MRI lumbar spine*- While an MRI is essential for confirming the diagnosis, localizing the lesion (usually a massive **disc herniation**), and guiding surgery, it should not delay the time-sensitive preparation for emergency intervention.- The clinical findings alone are sufficient to expedite surgery, as the critical factor is minimizing the risk of **permanent deficit**.*High-dose corticosteroids*- Corticosteroids are not the standard of care for CES, as the pathology is typically **mechanical compression** of the cauda equina nerve roots, not inflammation or edema treatable by steroids.- They are indicated primarily in inflammatory spinal pathologies or acute **traumatic spinal cord injury**.*Bed rest and analgesia*- This conservative management is appropriate only for uncomplicated **lumbago** or self-limiting mechanical back pain without signs of severe neurological deficits like **saddle anesthesia**.- Delaying surgery by resorting to bed rest in CES guarantees a poorer outcome and risk of irreversible **neurological impairment**.*Physiotherapy*- Physiotherapy is crucial for **rehabilitation** following surgery to restore strength and mobility in patients recovering from CES.- It is contraindicated as an initial intervention in the acute stage, where the priority must be **immediate surgical relief** of nerve compression.

Q: A 33-year-old man presents with acute onset severe lower back pain radiating down both legs. He has bilateral leg weakness and urinary retention. MRI shows large central disc herniation at L4-L5. What is the most appropriate management?

Emergency surgical decompression. ***Emergency surgical decompression***- The combination of **bilateral leg weakness**, severe pain, and most critically, **urinary retention**, secondary to a **large central disc herniation**, indicates **Cauda Equina Syndrome (CES)**.- **Cauda Equina Syndrome** is a **neurosurgical emergency** requiring **immediate surgical decompression** to prevent permanent neurological deficits, such as irreversible bladder and bowel dysfunction.*Conservative management*- This approach is appropriate for patients with uncomplicated **radiculopathy** (sciatica) without progressive motor deficits or sphincter dysfunction.- Delaying surgery in the presence of **Cauda Equina Syndrome** leads to a high risk of permanent and debilitating neurological damage.*Epidural steroid injection*- These injections are used for managing persistent, isolated **radicular pain** due to disc herniation that does not respond to oral medication and rest.- They do not address the urgent **mechanical compression** on the cauda equina nerves that is causing the emergent neurological deficit and sphincter dysfunction.*Physiotherapy*- Physiotherapy is crucial for rehabilitation following surgery or for managing subacute and chronic mechanical back pain.- Starting therapy immediately in acute **Cauda Equina Syndrome** is inappropriate and risks delaying necessary **surgical decompression**.*Bed rest*- Prolonged bed rest is generally discouraged for acute lower back pain due to risks of **deconditioning** and stiffness.- It is an ineffective and harmful action in a patient presenting with an **acute neurosurgical emergency** like **Cauda Equina Syndrome**.

Q: A 31-year-old man presents with acute severe lower back pain and bilateral leg weakness developing over 6 hours. He has urinary retention and saddle anesthesia. What is the most appropriate immediate management?

Emergency surgical decompression. ***Emergency surgical decompression*** - The presentation of acute severe back pain, bilateral leg weakness, **urinary retention**, and **saddle anesthesia** defines **Cauda Equina Syndrome (CES)**, which is a life-threatening surgical emergency. - **Urgent surgical decompression** (laminotomy/discectomy) is the most critical immediate management step, typically required within 48 hours, to alleviate nerve root compression and preserve neurological function. *MRI lumbar spine* - While an **MRI** is the definitive imaging modality required to confirm the diagnosis, the treatment (decompression) based on the clear clinical findings must be initiated simultaneously and not wait for the scan. - Delaying treatment while focusing solely on imaging can lead to irreversible damage to the lower motor neurons controlling bladder and bowel function. *High-dose corticosteroids* - Corticosteroids may be used in cases of **spinal cord trauma** or inflammatory conditions (e.g., transverse myelitis) to reduce edema, but they are not the primary treatment for mechanical CES. - Steroids lack proven efficacy in improving outcomes for CES caused by **acute mechanical compression** (e.g., massive disc herniation). *Bed rest and analgesia* - This conservative approach is appropriate for simple, self-limiting **lumbago** or uncomplicated radiculopathy, but it is wholly inadequate for CES. - CES requires immediate intervention; relying on bed rest guarantees progression of neurological deficits and permanent loss of **bladder and bowel control**. *Physiotherapy referral* - Physiotherapy is essential for rehabilitation *after* definitive surgical decompression and stabilization has been achieved. - Referral in the acute setting would delay emergency intervention and is contraindicated as movement could potentially worsen the underlying **mass effect** compressing the nerve roots.

Q: A 33-year-old man presents with acute onset severe lower back pain radiating down both legs. He has bilateral leg weakness and urinary retention. MRI shows large central disc herniation at L4-L5. What is the most appropriate management?

Emergency surgical decompression. ***Emergency surgical decompression***- The clinical triad (acute severe back pain, bilateral leg weakness/radiculopathy, and **urinary retention**) is diagnostic of **Cauda Equina Syndrome (CES)**, which is a neurosurgical emergency.- Immediate surgical decompression is mandatory, usually requiring a **laminectomy** or **discectomy**, to relieve pressure on the cauda equina nerve roots and maximize the chance of functional recovery. *Conservative management*- This approach is appropriate for patients with uncomplicated spinal conditions like **non-specific back pain** or mild sciatica without progressive neurological deficits or CES.- Delaying surgery in the presence of CES, characterized by bladder dysfunction, is associated with a poor prognosis for recovery of **sphincter function**.*Epidural steroid injection*- Steroid injections are typically used to treat radicular pain caused by **disc herniation** or **spinal stenosis** when symptoms are purely pain-related or mild/moderate.- It is ineffective in managing the severe mechanical compression and acute neurological deficits of CES (leg weakness, **urinary retention**) and would waste valuable time.*Physiotherapy*- While important for recovery, physiotherapy is part of the **rehabilitation phase** following successful surgical intervention, not the definitive acute treatment for CES.- Initiating physiotherapy before addressing the urgent structural compression increases the risk of **permanent neurological deficits** due to continued nerve root impingement.*Bed rest*- Prolonged bed rest is generally discouraged for disc pathologies as it can lead to deconditioning and increased pain intensity.- It is never the appropriate management for CES, as the underlying mechanical problem requires **urgent surgical removal** of the compressive force (the herniated disc).

Orthopaedics & MSK UK Medical PG Practice Questions and MCQs

Question 1: A 29-year-old man presents with acute onset severe lower back pain and bilateral leg weakness after heavy lifting. He has saddle anesthesia and urinary retention. MRI shows central disc herniation at L4-L5. What is the expected outcome with prompt treatment?

A. Complete recovery in all cases
B. Good functional recovery in most cases
C. Variable outcome depending on delay (Correct Answer)
D. Poor prognosis regardless of treatment
E. Recovery limited to bladder function

Explanation: ***Variable outcome depending on delay***- Cauda Equina Syndrome (CES) is a neurological emergency where prognosis, especially for **bladder** and **bowel function**, is highly dependent on the **time to surgical decompression**.- Delays in treatment, typically beyond 24-48 hours, significantly increase the risk of **permanent neurological deficits**, making the outcome highly unpredictable and variable.*Complete recovery in all cases*- Even with prompt surgical intervention, severe or prolonged compression often leads to some **residual neurological deficit**, particularly affecting **bladder, bowel, and sexual function**.- While early treatment improves outcomes, **complete recovery** in all aspects is not guaranteed due to the vulnerability of the cauda equina nerve roots to ischemic damage.*Good functional recovery in most cases*- The likelihood of **good functional recovery**, especially regarding **sphincter control**, is critically dependent on the timing of intervention and the severity of pre-operative deficits.- Many patients, particularly if surgery is delayed, experience long-term defects, making "good functional recovery in most cases" an overly optimistic assessment.*Poor prognosis regardless of treatment*- Prompt surgical decompression is crucial and significantly improves motor and sensory outcomes, offering the best chance for recovery of **sphincter function** and overall neurological improvement.- The prognosis for CES is highly dependent on the timeliness of treatment, meaning a poor prognosis is not inevitable if intervention is swift.*Recovery limited to bladder function*- Cauda Equina Syndrome (CES) affects multiple neurological functions, including **motor function** (leg weakness), **sensory function** (saddle anesthesia), and **autonomic function** (bladder and bowel control).- When recovery occurs, it typically involves improvements across motor, sensory, and autonomic domains, not exclusively bladder function, although bladder and bowel function are often the slowest and most challenging to recover fully.

Question 2: A 45-year-old man presents with acute severe lower back pain and leg weakness. MRI shows large central disc herniation with cauda equina compression. What is the surgical urgency?

A. Elective (weeks)
B. Urgent (days)
C. Emergency (hours) (Correct Answer)
D. No surgery needed
E. Depends on symptoms

Explanation: ***Emergency (hours)***- **Cauda Equina Syndrome (CES)** caused by acute central disc herniation requires immediate surgical decompression, ideally within **6 to 24 hours**, to maximize the chances of recovering full **neurological function**.- Delaying intervention significantly increases the risk of permanent disabling deficits, particularly **bladder and bowel incontinence** and **irreversible muscle weakness**.*Elective (weeks)*- Elective scheduling is appropriate only for stable conditions or those where chronic pain management is the primary goal, not for acute **nerve root compression syndromes**.- Delaying care by weeks in a confirmed CES case guarantees a poor prognosis regarding **sphincter and motor function**.*Urgent (days)*- While CES is highly urgent, characterizing it over *days* risks missing the critical window for decompression; the condition deteriorates rapidly.- Intervention for CES must be initiated immediately upon diagnosis (within **hours**), differentiating it from conditions that can safely wait 24–72 hours.*No surgery needed*- A mass lesion (large central disc herniation) causing acute **cauda equina compression** will not resolve adequately through conservative management alone.- Surgery is necessary to mechanically relieve the pressure on the nerve roots and prevent **permanent paralysis and sensory loss**.*Depends on symptoms*- The provided clinical presentation (acute severe low back pain and **leg weakness**) already suggests significant neurological compromise.- The combination of symptoms and the confirmed **cauda equina compression** on MRI elevates this to a non-negotiable surgical emergency, regardless of the precise degree of **sphincter dysfunction** at presentation.

Question 3: A 24-year-old man presents with acute onset severe lower back pain and bilateral leg weakness. He has urinary retention and saddle anesthesia. What is the time frame for surgical intervention?

A. Within 6 hours
B. Within 24-48 hours (Correct Answer)
C. Within 1 week
D. Within 1 month
E. No time limit

Explanation: ***Within 24–48 hours*** - This clinical presentation (severe low back pain, bilateral weakness, urinary retention, and **saddle anesthesia**) defines **Cauda Equina Syndrome (CES)**, a true neurosurgical emergency. - Urgent **surgical decompression** performed within the **24–48 hour** window is critical to maximize the likelihood of recovery, especially of fragile **bladder and bowel function**. *Within 6 hours* - While immediate intervention is ideal and preferred, **6 hours** is often an unfeasible or highly strict cutoff given the variability in symptom presentation and necessary preparatory steps (MRI, planning). - The key critical window recognized for achieving maximal recovery after diagnosis of **CES** spans up to 48 hours. *Within 1 week* - Delaying surgical decompression past the 48-hour mark dramatically increases the risk of **irreversible neurological injury**, particularly to the **sacral roots** controlling continence. - This timeframe is too slow for an acute compressive syndrome that leads to potential permanent **paralysis** and disability. *Within 1 month* - A delay of one month ensures **permanent neurological deficits**, including irreversible loss of motor function and **bladder/bowel control**. - This time frame is irrelevant to the management of an acute, progressive **cauda equina compression**. *No time limit* - **Cauda Equina Syndrome** is an urgent condition where prolonged compression results in direct **ischemic injury** and necrosis of the spinal nerve roots. - Lack of timely decompression guarantees poor long-term outcome and **permanent functional disability**, thus a time limit is essential.

Question 4: A 72-year-old man presents with confusion and agitation 3 days after hip surgery. He sees people who aren't there and is disoriented to time and place. What is the most likely diagnosis?

A. Dementia
B. Postoperative delirium (Correct Answer)
C. Alcohol withdrawal
D. Depression
E. Anxiety

Explanation: ***Postoperative delirium*** - This diagnosis perfectly fits the clinical picture: an acute onset of confusion, agitation, and **visual hallucinations** (seeing people who aren't there) in an elderly patient following a major stressor like hip surgery. - Delirium is an **acute, fluctuating disturbance** of attention and cognition, and advanced age combined with recent surgery is the most common risk factor for the postoperative subtype.*Dementia* - Dementia is characterized by a **chronic, progressive decline** in memory and other cognitive domains, which is inconsistent with the acute change observed over 3 days. - While individuals with pre-existing dementia are at high risk for delirium, the acute change itself is defined as **superimposed delirium**, not just dementia.*Alcohol withdrawal* - This diagnosis (especially **delirium tremens**) can cause agitation and prominent visual or tactile hallucinations, but it requires a history of **heavy chronic alcohol use** which is not specified. - Symptoms typically peak 48–96 hours after cessation, and while the timing is plausible, the recent major surgery provides a more direct and common cause for the observed presentation in the absence of a known history of substance abuse.*Depression* - Depression presents with mood disturbances, anhedonia, and vegetative symptoms, but it does **not cause acute, global disorientation** or **frank visual hallucinations**. - Although severe depression can cause cognitive slowing (**pseudodementia**), it lacks the acute-onset, hyperactive agitated state frequently seen in delirium.*Anxiety* - Anxiety is characterized by excessive worry, tension, and autonomic symptoms, but it does **not cause acute disorientation** to time and place or complex **visual hallucinations**. - The patient's confusion and disorientation indicate a global disturbance of cortical function, which is not characteristic of primary anxiety disorders.

Question 5: A 24-year-old man presents with acute onset severe lower back pain and bilateral leg weakness after heavy lifting. He has saddle anesthesia and urinary retention. What is the most appropriate management?

A. MRI lumbar spine
B. Emergency surgical decompression (Correct Answer)
C. High-dose steroids
D. Bed rest and analgesia
E. Physiotherapy

Explanation: ***Emergency surgical decompression***- The patient presents with classic features of **Cauda Equina Syndrome (CES)**, characterized by acute lower back pain, bilateral leg weakness, **saddle anesthesia**, and **urinary retention**, necessitating immediate surgical intervention.- Urgent surgical decompression (laminectomy and removal of the compressive element, usually a massive disc herniation) is the definitive treatment and must be performed rapidly to maximize the chances of recovering **bowel and bladder function**.*MRI lumbar spine*- While an **MRI** is the gold standard for confirming the diagnosis, localizing the compression, and guiding the surgical approach, it is a diagnostic tool, not the definitive management itself for this surgical emergency.- Surgery should proceed as soon as possible after clinical suspicion, minimizing diagnostic delays which negatively impact the **prognosis** for bladder function.*High-dose steroids*- **Corticosteroids** are the cornerstone of management in conditions like acute traumatic spinal cord injury or transverse myelitis, helping to reduce edema and secondary injury.- They are generally ineffective as a primary treatment for neurologic deficits caused by **mechanical compression** by a herniated disc, which is the most common cause of CES.*Bed rest and analgesia*- This conservative approach is typically reserved for routine, **uncomplicated low back pain** or musculoskeletal strains without significant progressive neurologic deficits.- Applying only bed rest and analgesia to CES is inappropriate and risks permanent damage to the sacral and coccygeal nerve roots, leading to irreversible **neurologic disability**.*Physiotherapy*- **Physiotherapy** is an essential component of rehabilitation following surgical decompression and initial recovery in CES, helping patients regain strength and mobility.- It is contraindicated during the acute phase of severe mechanical compression and does not address the underlying need for **urgent nerve root decompression**.

Question 6: A 25-year-old man presents with acute onset severe lower back pain radiating down his left leg to the foot. He has difficulty walking and reports numbness in his left foot. Straight leg raise test is positive at 30 degrees. What is the most likely diagnosis?

A. Mechanical back pain
B. Lumbar disc herniation (Correct Answer)
C. Spinal stenosis
D. Cauda equina syndrome
E. Ankylosing spondylitis

Explanation: ***Lumbar disc herniation*** - The presentation of **acute onset severe lower back pain** radiating down the left leg to the foot, along with **numbness in the left foot** and difficulty walking, are classic signs of nerve root compression. - A **positive straight leg raise test at 30 degrees** is a strong indicator of nerve root irritation, highly suggestive of lumbar disc herniation. *Mechanical back pain* - **Mechanical back pain** is typically localized axial pain, aggravated by movement, and **does not cause radicular symptoms** or objective neurological deficits such as foot numbness or weakness. - This diagnosis would not explain the **positive straight leg raise test** or the specific neurological symptoms in the left leg and foot. *Spinal stenosis* - **Spinal stenosis** usually affects older patients, presenting with **neurogenic claudication** (leg pain relieved by sitting or forward flexion) rather than acute, severe unilateral radiculopathy in a 25-year-old. - The onset is typically insidious and chronic, not acute, and it often involves bilateral leg symptoms. *Cauda equina syndrome* - **Cauda equina syndrome** is a serious emergency characterized by **saddle anesthesia**, **bowel or bladder dysfunction** (e.g., urinary retention), and often bilateral leg weakness, none of which are reported here. - While it can cause severe lower back pain and leg symptoms, the absence of these hallmark

Question 7: A 45-year-old man presents with acute severe lower back pain after lifting heavy weights. He has bilateral leg weakness, saddle anesthesia, and urinary retention. What is the most appropriate immediate management?

A. MRI lumbar spine
B. Emergency surgical decompression (Correct Answer)
C. High-dose corticosteroids
D. Bed rest and analgesia
E. Physiotherapy

Explanation: ***Emergency surgical decompression***- This clinical presentation (saddle anesthesia, bilateral weakness, urinary retention following heavy lifting) is diagnostic of **Cauda Equina Syndrome (CES)**.- **Emergency surgical decompression**, ideally within 24–48 hours of symptom onset, is mandatory to preserve neurological function and optimize recovery of **bladder/bowel control**.*MRI lumbar spine*- While an MRI is essential for confirming the diagnosis, localizing the lesion (usually a massive **disc herniation**), and guiding surgery, it should not delay the time-sensitive preparation for emergency intervention.- The clinical findings alone are sufficient to expedite surgery, as the critical factor is minimizing the risk of **permanent deficit**.*High-dose corticosteroids*- Corticosteroids are not the standard of care for CES, as the pathology is typically **mechanical compression** of the cauda equina nerve roots, not inflammation or edema treatable by steroids.- They are indicated primarily in inflammatory spinal pathologies or acute **traumatic spinal cord injury**.*Bed rest and analgesia*- This conservative management is appropriate only for uncomplicated **lumbago** or self-limiting mechanical back pain without signs of severe neurological deficits like **saddle anesthesia**.- Delaying surgery by resorting to bed rest in CES guarantees a poorer outcome and risk of irreversible **neurological impairment**.*Physiotherapy*- Physiotherapy is crucial for **rehabilitation** following surgery to restore strength and mobility in patients recovering from CES.- It is contraindicated as an initial intervention in the acute stage, where the priority must be **immediate surgical relief** of nerve compression.

Question 8: A 33-year-old man presents with acute onset severe lower back pain radiating down both legs. He has bilateral leg weakness and urinary retention. MRI shows large central disc herniation at L4-L5. What is the most appropriate management?

A. Conservative management
B. Epidural steroid injection
C. Emergency surgical decompression (Correct Answer)
D. Physiotherapy
E. Bed rest

Explanation: ***Emergency surgical decompression***- The combination of **bilateral leg weakness**, severe pain, and most critically, **urinary retention**, secondary to a **large central disc herniation**, indicates **Cauda Equina Syndrome (CES)**.- **Cauda Equina Syndrome** is a **neurosurgical emergency** requiring **immediate surgical decompression** to prevent permanent neurological deficits, such as irreversible bladder and bowel dysfunction.*Conservative management*- This approach is appropriate for patients with uncomplicated **radiculopathy** (sciatica) without progressive motor deficits or sphincter dysfunction.- Delaying surgery in the presence of **Cauda Equina Syndrome** leads to a high risk of permanent and debilitating neurological damage.*Epidural steroid injection*- These injections are used for managing persistent, isolated **radicular pain** due to disc herniation that does not respond to oral medication and rest.- They do not address the urgent **mechanical compression** on the cauda equina nerves that is causing the emergent neurological deficit and sphincter dysfunction.*Physiotherapy*- Physiotherapy is crucial for rehabilitation following surgery or for managing subacute and chronic mechanical back pain.- Starting therapy immediately in acute **Cauda Equina Syndrome** is inappropriate and risks delaying necessary **surgical decompression**.*Bed rest*- Prolonged bed rest is generally discouraged for acute lower back pain due to risks of **deconditioning** and stiffness.- It is an ineffective and harmful action in a patient presenting with an **acute neurosurgical emergency** like **Cauda Equina Syndrome**.

Question 9: A 31-year-old man presents with acute severe lower back pain and bilateral leg weakness developing over 6 hours. He has urinary retention and saddle anesthesia. What is the most appropriate immediate management?

A. MRI lumbar spine
B. High-dose corticosteroids
C. Emergency surgical decompression (Correct Answer)
D. Bed rest and analgesia
E. Physiotherapy referral

Explanation: ***Emergency surgical decompression*** - The presentation of acute severe back pain, bilateral leg weakness, **urinary retention**, and **saddle anesthesia** defines **Cauda Equina Syndrome (CES)**, which is a life-threatening surgical emergency. - **Urgent surgical decompression** (laminotomy/discectomy) is the most critical immediate management step, typically required within 48 hours, to alleviate nerve root compression and preserve neurological function. *MRI lumbar spine* - While an **MRI** is the definitive imaging modality required to confirm the diagnosis, the treatment (decompression) based on the clear clinical findings must be initiated simultaneously and not wait for the scan. - Delaying treatment while focusing solely on imaging can lead to irreversible damage to the lower motor neurons controlling bladder and bowel function. *High-dose corticosteroids* - Corticosteroids may be used in cases of **spinal cord trauma** or inflammatory conditions (e.g., transverse myelitis) to reduce edema, but they are not the primary treatment for mechanical CES. - Steroids lack proven efficacy in improving outcomes for CES caused by **acute mechanical compression** (e.g., massive disc herniation). *Bed rest and analgesia* - This conservative approach is appropriate for simple, self-limiting **lumbago** or uncomplicated radiculopathy, but it is wholly inadequate for CES. - CES requires immediate intervention; relying on bed rest guarantees progression of neurological deficits and permanent loss of **bladder and bowel control**. *Physiotherapy referral* - Physiotherapy is essential for rehabilitation *after* definitive surgical decompression and stabilization has been achieved. - Referral in the acute setting would delay emergency intervention and is contraindicated as movement could potentially worsen the underlying **mass effect** compressing the nerve roots.

Question 10: A 33-year-old man presents with acute onset severe lower back pain radiating down both legs. He has bilateral leg weakness and urinary retention. MRI shows large central disc herniation at L4-L5. What is the most appropriate management?

A. Conservative management
B. Epidural steroid injection
C. Emergency surgical decompression (Correct Answer)
D. Physiotherapy
E. Bed rest

Explanation: ***Emergency surgical decompression***- The clinical triad (acute severe back pain, bilateral leg weakness/radiculopathy, and **urinary retention**) is diagnostic of **Cauda Equina Syndrome (CES)**, which is a neurosurgical emergency.- Immediate surgical decompression is mandatory, usually requiring a **laminectomy** or **discectomy**, to relieve pressure on the cauda equina nerve roots and maximize the chance of functional recovery. *Conservative management*- This approach is appropriate for patients with uncomplicated spinal conditions like **non-specific back pain** or mild sciatica without progressive neurological deficits or CES.- Delaying surgery in the presence of CES, characterized by bladder dysfunction, is associated with a poor prognosis for recovery of **sphincter function**.*Epidural steroid injection*- Steroid injections are typically used to treat radicular pain caused by **disc herniation** or **spinal stenosis** when symptoms are purely pain-related or mild/moderate.- It is ineffective in managing the severe mechanical compression and acute neurological deficits of CES (leg weakness, **urinary retention**) and would waste valuable time.*Physiotherapy*- While important for recovery, physiotherapy is part of the **rehabilitation phase** following successful surgical intervention, not the definitive acute treatment for CES.- Initiating physiotherapy before addressing the urgent structural compression increases the risk of **permanent neurological deficits** due to continued nerve root impingement.*Bed rest*- Prolonged bed rest is generally discouraged for disc pathologies as it can lead to deconditioning and increased pain intensity.- It is never the appropriate management for CES, as the underlying mechanical problem requires **urgent surgical removal** of the compressive force (the herniated disc).

Question 11: A 41-year-old man presents with acute severe lower back pain and bilateral leg weakness developing over 4 hours. He has urinary retention and saddle anesthesia. What is the most appropriate immediate management?

A. MRI lumbar spine
B. Emergency decompressive surgery (Correct Answer)
C. High-dose corticosteroids
D. Bed rest and analgesia
E. Urgent neurology referral

Explanation: ***Emergency decompressive surgery***- **Cauda equina syndrome (CES)** is a neurosurgical emergency characterized by severe lower back pain, **bilateral leg weakness**, **urinary retention**, and **saddle anesthesia**.- **Emergency decompressive surgery** is the most appropriate immediate management to relieve pressure on the nerve roots, ideally within **48 hours**, to maximize recovery of bowel, bladder, and motor function.*MRI lumbar spine*- An **MRI lumbar spine** is the gold standard for diagnosing and localizing the compression causing CES.- While essential, it is a diagnostic tool, and the definitive treatment (surgery) should be initiated without undue delay once CES is clinically suspected, as the clinical picture is highly indicative.*High-dose corticosteroids*- **High-dose corticosteroids** are primarily used for inflammatory conditions affecting the spinal cord or brain, such as acute spinal cord injury or demyelinating diseases.- They are not the definitive treatment for mechanical compression of the cauda equina nerve roots, which requires surgical decompression.*Bed rest and analgesia*- **Bed rest and analgesia** are suitable for routine, uncomplicated low back pain without signs of neurological compromise.- Applying this conservative approach in a suspected case of CES with **progressive neurological deficits** would significantly delay definitive treatment and risk permanent disability.*Urgent neurology referral*- An **urgent neurology referral** (specifically to a neurosurgeon or orthopedic spine surgeon) is a necessary step for consultation and surgical planning.- However, it is a referral for management, not the definitive *immediate management* action itself, which in this critical scenario is the emergency operation.

Question 12: A 23-year-old man presents with acute onset severe lower back pain after lifting heavy weights. He has bilateral leg weakness, saddle anesthesia, and urinary retention. What is the most appropriate immediate management?

A. MRI lumbar spine
B. Emergency surgical decompression (Correct Answer)
C. High-dose corticosteroids
D. Bed rest and analgesia
E. Physiotherapy

Explanation: ***Emergency surgical decompression***- The combination of **acute severe lower back pain**, **bilateral leg weakness**, **saddle anesthesia**, and **urinary retention** is the classic presentation of **Cauda Equina Syndrome (CES)**, which is a neurosurgical emergency.- Immediate surgical decompression is the definitive treatment required to relieve pressure on the cauda equina nerve roots and prevent **permanent neurological deficits**, especially irreversible **bladder and bowel dysfunction**.*MRI lumbar spine*- While an **MRI lumbar spine** is crucial for diagnosing **Cauda Equina Syndrome** and localizing the lesion, it is a diagnostic tool, not the immediate management itself.- Delaying definitive surgical treatment by solely ordering an MRI can lead to **worsening neurological outcomes** if decompression is not performed urgently.*High-dose corticosteroids*- **High-dose corticosteroids** are typically used in conditions like acute spinal cord injury to reduce inflammation, but their benefit in **Cauda Equina Syndrome** is not established and they do not address the mechanical compression.- They are not a substitute for **surgical decompression** in CES and can have significant side effects, further delaying appropriate treatment.*Bed rest and analgesia*- **Bed rest and analgesia** are appropriate for uncomplicated low back pain or minor disc herniations without neurological compromise.- In the presence of **bilateral leg weakness, saddle anesthesia, and urinary retention**, indicating **Cauda Equina Syndrome**, this management is wholly insufficient and will lead to **permanent neurological damage**.*Physiotherapy*- **Physiotherapy** is beneficial for chronic back pain and rehabilitation after an injury or surgery, but it is contraindicated in the acute phase of **Cauda Equina Syndrome**.- Performing physiotherapy without addressing the underlying **compressive lesion** can exacerbate symptoms and worsen neurological deficits.

Question 13: A 49-year-old woman presents with an 18-month history of lower back pain and bilateral buttock pain. She reports morning stiffness lasting 75 minutes that improves with activity. She has a history of psoriasis and inflammatory bowel disease. HLA-B27 is positive. MRI sacroiliac joints shows bilateral bone marrow oedema and erosions. She has tried NSAIDs with partial relief. What is the most appropriate next step in management according to NICE guidelines?

A. Add sulfasalazine to current treatment
B. Commence anti-TNF biological therapy (e.g., adalimumab)
C. Add methotrexate to current treatment
D. Trial of two different NSAIDs at maximum dose for 4 weeks each with physiotherapy before considering biologics (Correct Answer)
E. Commence oral prednisolone 20mg daily

Explanation: ***Trial of two different NSAIDs at maximum dose for 4 weeks each with physiotherapy before considering biologics*** - According to **NICE guidelines (NG65)** for axial spondyloarthritis, patients must demonstrate an inadequate response to at least **two different NSAIDs** used at the maximum tolerated dose for 4 weeks each before escalating therapy to biologics. - **Physiotherapy** and a structured exercise program are fundamental **first-line non-pharmacological interventions** that should be maximized alongside NSAIDs. *Add sulfasalazine to current treatment* - **Sulfasalazine** is a disease-modifying antirheumatic drug (DMARD) that is effective for **peripheral arthritis** associated with spondyloarthritis but has **no proven efficacy for axial (spinal) disease**. - While the patient has IBD, adding sulfasalazine specifically for her **sacroiliitis** is not the appropriate next step in management according to guidelines. *Commence anti-TNF biological therapy (e.g., adalimumab)* - **Anti-TNF biological therapy** is indicated only if the disease remains active (e.g., **BASDAI score ≥4**) after the failure of conventional treatment, which includes an adequate trial of **two different NSAIDs**. - Starting biologics prematurely, without completing the **NICE-mandated NSAID trial**, is not in line with current guidelines. *Add methotrexate to current treatment* - Similar to sulfasalazine, **methotrexate** is considered ineffective for the treatment of **axial spondyloarthritis** and spinal inflammation. - It may be used for **psoriatic skin disease** or peripheral joint involvement, but it is not the recommended next step for managing worsening **inflammatory back pain**. *Commence oral prednisolone 20mg daily* - **Oral corticosteroids** are generally not recommended for the long-term management of axial spondyloarthritis due to a lack of strong evidence for sustained efficacy in axial symptoms and the risk of significant **side effects**. - Systemic steroids are not part of the standard **NICE treatment algorithm** for axial spondyloarthritis. Local corticosteroid injections might be considered for specific peripheral joints, but not systemic use for axial disease.

Question 14: A 74-year-old woman undergoes hemiarthroplasty for a displaced intracapsular neck of femur fracture. She has a history of atrial fibrillation, ischaemic heart disease, and type 2 diabetes mellitus. Post-operatively she develops confusion, pyrexia of 38.2°C, and a wound with purulent discharge on day 4. Blood cultures grow Staphylococcus aureus sensitive to flucloxacillin. What is the most appropriate definitive management?

A. Six weeks of intravenous flucloxacillin
B. Revision surgery to remove prosthesis with antibiotic spacer insertion (Correct Answer)
C. Washout of joint and debridement with prosthesis retention and long-term antibiotics
D. Two weeks intravenous flucloxacillin followed by four weeks oral flucloxacillin
E. Arthroscopic washout and two weeks intravenous antibiotics

Explanation: ***Revision surgery to remove prosthesis with antibiotic spacer insertion***- In the context of an acute **prosthetic joint infection (PJI)** with systemic sepsis and **Staphylococcus aureus** bacteraemia, removing the infected hardware is the definitive step to achieve **source control**.- A **two-stage revision** or a Girdlestone-type procedure with an **antibiotic spacer** is indicated when the risk of biofilm persistence is high, ensuring the highest rate of infection eradication.*Six weeks of intravenous flucloxacillin*- Systemic antibiotics alone are insufficient for **definitive management** because bacteria form a protective **biofilm** on the surface of the prosthetic material.- Failure to surgically address the hardware will inevitably lead to **treatment failure** and recurrence of infection once antibiotics are ceased.*Washout of joint and debridement with prosthesis retention and long-term antibiotics*- This protocol, known as **DAIR** (Debridement, Antibiotics, and Implant Retention), is typically reserved for early infections (<3-4 weeks) with organisms less virulent than **S. aureus** and without systemic sepsis, having a high failure rate in such cases.- Given the patient's **systemic symptoms** (pyrexia, confusion) and **Staphylococcus aureus** bacteraemia, a more aggressive surgical intervention involving implant removal is preferred for definitive clearance due to the high risk of biofilm persistence.*Two weeks intravenous flucloxacillin followed by four weeks oral flucloxacillin*- This antibiotic duration is often used post-operatively for prophylaxis or minor infections but does not constitute **definitive management** in the presence of an infected prosthesis with systemic signs.- Without removing the nidus of infection (the **hemiarthroplasty**), oral step-down therapy will not penetrate the established **biofilm** effectively, leading to treatment failure.*Arthroscopic washout and two weeks intravenous antibiotics*- **Arthroscopic debridement** is inadequate for prosthetic joint infections, especially in the hip, as it does not allow for thorough **synovectomy** or exchange of modular components, which is crucial for infection control.- **Open debridement** or full revision is required to adequately reduce the bacterial load and manage the infected tissue effectively, particularly with established **purulent discharge** and systemic infection.

Question 15: A 68-year-old man with multiple myeloma presents with a 5-week history of progressively worsening thoracic back pain. Over the past 3 days he has developed difficulty walking and leg weakness. On examination, power is 4/5 in hip flexion bilaterally, 3/5 in knee extension, and 2/5 in ankle dorsiflexion. He has a sensory level at T10. Anal tone is reduced. What is the most appropriate immediate management?

A. Commence intravenous dexamethasone 16mg and arrange urgent MRI spine within 24 hours (Correct Answer)
B. Arrange routine outpatient MRI and commence oral analgesia
C. Immediate surgical decompression without imaging
D. Commence radiotherapy and arrange MRI within 1 week
E. Commence intravenous antibiotics and arrange CT-guided biopsy

Explanation: ***Commence intravenous dexamethasone 16mg and arrange urgent MRI spine within 24 hours*** - This patient presents with **Metastatic Spinal Cord Compression (MSCC)**, an oncological emergency requiring immediate **high-dose corticosteroids** to reduce peritumoral edema and preserve neurological function. - An **urgent MRI of the whole spine** is the gold standard investigation and must be performed within **24 hours** to confirm the level of compression and guide definitive management (surgery or radiotherapy). *Arrange routine outpatient MRI and commence oral analgesia* - Routine imaging is inappropriate for suspected **MSCC**, as neurological deficits can progress rapidly and become irreversible if not addressed promptly. - Delaying diagnosis and definitive treatment with an outpatient MRI would likely lead to permanent **neurological deficits** given the progressive motor weakness and reduced anal tone. *Immediate surgical decompression without imaging* - Surgical decompression should never be performed without prior imaging, as it is essential to visualize the **exact spinal level**, the extent of the **tumor mass**, and rule out multiple compression sites. - MRI is necessary to determine if the patient is a candidate for **surgical decompression** versus radiotherapy based on spinal stability, tumor location, and patient comorbidities. *Commence radiotherapy and arrange MRI within 1 week* - While **Multiple Myeloma** is a radiosensitive tumor, radiotherapy cannot be initiated until the exact compression site and extent are defined by an **urgent MRI**. - A one-week delay for imaging is far too long for a patient already experiencing **progressive motor weakness** and reduced **anal tone**, as irreversible damage can occur within hours to days. *Commence intravenous antibiotics and arrange CT-guided biopsy* - This management plan is typically reserved for suspected **spinal epidural abscess** or other infectious causes, which are less likely given the patient's known history of **multiple myeloma**. - Prioritizing a biopsy over immediate **spinal cord decompression** (via steroids and subsequent surgery/radiation) would result in avoidable and potentially permanent neurological damage.

Question 16: A 57-year-old man presents to the Emergency Department with a 48-hour history of severe lower back pain, bilateral leg weakness, and difficulty passing urine. He reports reduced sensation in the perineal area. On examination, power is 3/5 in both legs with absent ankle reflexes bilaterally. Post-void residual volume is 650ml. What is the time-critical management priority?

A. Immediate MRI spine and urgent neurosurgical referral for decompression within 48 hours of symptom onset (Correct Answer)
B. Commence high-dose intravenous dexamethasone and arrange elective MRI
C. Insert urinary catheter and arrange outpatient MRI within 2 weeks
D. Commence broad-spectrum antibiotics and arrange urgent CT spine
E. Bed rest, analgesia, and physiotherapy review

Explanation: ***Immediate MRI spine and urgent neurosurgical referral for decompression within 48 hours of symptom onset*** - This patient presents with classic features of **Cauda Equina Syndrome (CES)**, including bilateral leg weakness, **saddle anesthesia**, and urinary retention, which is a **surgical emergency**. - An **immediate MRI** is required to confirm compression, and surgical decompression must be performed as soon as possible, ideally within **48 hours of symptom onset**, to prevent permanent neurological damage. *Commence high-dose intravenous dexamethasone and arrange elective MRI* - High-dose steroids are the priority for **Metastatic Spinal Cord Compression (MSCC)** to reduce edema, but CES is typically caused by **disc herniation** requiring mechanical decompression. - Arranging an **elective MRI** is dangerous, as delays in diagnosis and treatment of CES lead to irreversible **bladder, bowel, and sexual dysfunction**. *Insert urinary catheter and arrange outpatient MRI within 2 weeks* - While a catheter is necessary to manage **urinary retention** as a symptom, it does not address the underlying **thecal sac compression**. - An **outpatient MRI** timeframe of 2 weeks is entirely inappropriate for an acute neurological deficit; diagnosis must occur within hours, not weeks. *Commence broad-spectrum antibiotics and arrange urgent CT spine* - Antibiotics are only indicated if **spinal epidural abscess** or discitis is suspected, which is not the primary presentation here; the main management remains urgent imaging and decompression. - **CT spine** is inferior to MRI for visualizing **soft tissue pathology**, such as a massive central disc prolapse, which is the most common cause of CES. *Bed rest, analgesia, and physiotherapy review* - This conservative management approach is appropriate for simple **mechanical low back pain** but is entirely contraindicated in the presence of **red flag symptoms** like those seen in CES. - Delaying surgical intervention by recommending bed rest and physiotherapy in the setting of **motor deficits** and bladder dysfunction constitutes medical negligence and can lead to permanent disability.

Question 17: A 70-year-old man sustains an undisplaced Garden I intracapsular neck of femur fracture. He has severe osteoarthritis of the ipsilateral hip with significant pain and functional limitation pre-injury. He was mobilizing with two crutches. What is the most appropriate surgical management?

A. Cannulated screw fixation
B. Dynamic hip screw fixation
C. Hemiarthroplasty
D. Total hip replacement (Correct Answer)
E. Conservative management with protected weight-bearing

Explanation: ***Total hip replacement***- Although Garden I fractures are typically managed with internal fixation, the presence of **pre-existing symptomatic osteoarthritis** makes total hip replacement (THR) the definitive choice to address both the fracture and the chronic joint pain.- NICE guidelines suggest **THR** as a primary option for intracapsular fractures when it provides a better long-term functional outcome, especially in patients with joint disease that would otherwise require future surgery.*Cannulated screw fixation*- This method is used for stable, **undisplaced fractures** in patients without pre-existing joint pathology, but would leave the patient with persistent **osteoarthritic pain**.- It has a risk of **avascular necrosis** or non-union, and does not address the underlying degenerative disease of the acetabulum.*Dynamic hip screw fixation*- This is the standard treatment for **extracapsular intertrochanteric fractures**, not for intracapsular neck of femur fractures.- Using a DHS in the presence of severe **hip osteoarthritis** would fail to provide functional relief for the patient's pre-injury disability.*Hemiarthroplasty*- This procedure replaces the femoral head but leaves the arthritic **acetabulum** intact, which would lead to continued pain due to the pre-existing joint surface damage.- It is generally reserved for older, less active patients with **displaced fractures** who do not have symptomatic hip osteoarthritis.*Conservative management with protected weight-bearing*- This is rarely indicated for femoral neck fractures due to the high risk of **displacement**, non-union, and complications of immobility like **venous thromboembolism**.- It would be considered only for patients who are **medically unfit** for any form of anesthesia or surgery.

Question 18: A 39-year-old woman with known ulcerative colitis presents with a 20-week history of lower back pain and stiffness. The pain is worse in the early morning with stiffness lasting 2 hours. She also reports pain and swelling in her right knee and left ankle. Examination reveals reduced lumbar spine flexion with a Schober's test of 3cm (normal >5cm). What is the most appropriate initial management?

A. Methotrexate and physiotherapy
B. NSAIDs and structured exercise programme
C. Anti-TNF therapy (adalimumab) and physiotherapy
D. Oral prednisolone and DMARDs
E. Sulfasalazine and physiotherapy (Correct Answer)

Explanation: ***Sulfasalazine and physiotherapy*** - **Sulfasalazine** is the preferred **DMARD** for enteropathic arthritis, effectively managing both **peripheral joint involvement** and supporting the underlying **ulcerative colitis**. - **Physiotherapy** and a structured exercise program are crucial for improving **spinal mobility** and addressing the reduced lumbar flexion, as indicated by the **Schober's test**. *Methotrexate and physiotherapy* - **Methotrexate** is generally ineffective for the **axial disease** component (spine and sacroiliac joints) of spondyloarthropathies. - While beneficial for some peripheral arthritis, it's often avoided as a first-line DMARD in patients with active **inflammatory bowel disease** due to potential GI irritation. *NSAIDs and structured exercise programme* - **NSAIDs** are typically first-line for inflammatory back pain but are used with extreme caution in patients with ulcerative colitis due to a significant risk of triggering an **IBD flare**. - Although exercise is important, NSAIDs alone do not provide disease-modifying benefits for progressive **peripheral arthritis** or long-term management in IBD patients. *Anti-TNF therapy (adalimumab) and physiotherapy* - **Anti-TNF agents** like adalimumab are highly effective for both inflammatory bowel disease and spondyloarthritis but are reserved for cases that have **failed conventional DMARD therapy**. - Due to their high cost and potential for serious side effects, including **infections**, they are not considered the initial management step. *Oral prednisolone and DMARDs* - **Oral corticosteroids** are not recommended for the long-term management of spondyloarthritis due to their well-known **systemic side effects**. - While they can manage acute IBD flares, they do not offer a disease-modifying effect for the skeletal manifestations and are not a suitable first-line agent for sustained remission of spondyloarthritis.

Question 19: Which of the following represents the correct percentage of femoral head blood supply derived from the medial circumflex femoral artery in adults?

A. 40-50%
B. 50-60%
C. 60-70%
D. 70-80% (Correct Answer)
E. 80-90%

Explanation: ***70-80%***- In adults, the **medial circumflex femoral artery** is the dominant source of blood supply to the femoral head, accounting for approximately **70-80%** of its perfusion.- It gives rise to the **superior and inferior retinacular arteries**, which are critical vessels frequently disrupted in intracapsular femoral neck fractures, leading to **avascular necrosis**.*40-50%*- This range significantly underestimates the contribution of the medial circumflex femoral artery, which effectively provides the vast majority of **intra-articular** blood flow.- Such a low percentage would imply a higher relative contribution from the **lateral circumflex** or **foveal arteries** than what is anatomically present in adults.*50-60%*- While the medial circumflex is the primary source, this range does not reflect its true clinical dominance observed in **orthopaedic anatomy** and angiography.- At this percentage, the femoral head would be less susceptible to total ischemia during **displaced neck fractures** than it actually is.*60-70%*- This value is closer to the truth but still falls short of the anatomical standard described in most surgical texts for the **retinacular system**.- The medial circumflex femoral artery consistently provides over **two-thirds** of the total supply, making this estimate slightly too low.*80-90%*- Although the medial circumflex is highly dominant, an **80-90%** estimate minimizes the essential minor contributions from other vessels.- The remaining **20-30%** of supply is reliably shared between the **lateral circumflex femoral artery** and the **artery of the ligamentum teres** (foveal artery).

Question 20: A 53-year-old woman presents with a 6-month history of lower back pain radiating into both buttocks and posterior thighs. The pain is worse when walking and standing, and is relieved by sitting or leaning forward. She reports being able to walk further when pushing a shopping trolley. Neurological examination is normal. What is the most likely diagnosis?

A. Lumbar spinal stenosis (Correct Answer)
B. Bilateral L5/S1 disc prolapse
C. Peripheral vascular disease
D. Ankylosing spondylitis
E. Cauda equina syndrome

Explanation: ***Lumbar spinal stenosis*** - This presentation is classic for **neurogenic claudication**, where lower back pain radiating to the buttocks and thighs is exacerbated by walking and standing (spinal extension) and relieved by sitting or leaning forward (spinal flexion). - The **shopping trolley sign**, where leaning forward allows walking further, specifically indicates lumbar spinal stenosis as it widens the spinal canal and reduces compression on neural elements. *Bilateral L5/S1 disc prolapse* - **Disc prolapse** typically causes radicular pain with a more acute onset and often follows specific dermatomal patterns, rather than the postural-dependent claudication seen here. - While it can cause bilateral leg pain, the characteristic relief with **spinal flexion** (sitting or leaning forward) is not a hallmark of disc herniation. *Peripheral vascular disease* - This condition causes **vascular claudication**, where leg pain is purely exertional (triggered by walking a certain distance) and relieved rapidly by **standing still** (rest), not by changes in spinal posture. - Unlike neurogenic claudication, it is not improved by spinal flexion, and physical examination often reveals **absent or diminished peripheral pulses**. *Ankylosing spondylitis* - **Ankylosing spondylitis** is characterized by **inflammatory back pain**, which typically improves with activity and is worse with rest or in the morning, contrasting with pain worsening on standing/walking. - It usually affects younger individuals and is associated with **morning stiffness** and progressive stiffness of the spine, not the intermittent claudication pattern. *Cauda equina syndrome* - This is a serious condition requiring urgent intervention, presenting with **saddle anesthesia**, bowel or bladder dysfunction, and significant **motor weakness** or sensory loss in the lower extremities. - The patient's **normal neurological examination** makes cauda equina syndrome an unlikely diagnosis in this case.

Question 21: A 76-year-old woman sustains a trochanteric neck of femur fracture with a reverse oblique pattern on radiographs. She is independently mobile with one stick. Which of the following is the most appropriate surgical fixation method?

A. Dynamic hip screw with anti-rotation screw
B. Intramedullary nail (Correct Answer)
C. Hemiarthroplasty
D. Cannulated screws
E. Total hip replacement

Explanation: ***Intramedullary nail*** - A **reverse oblique** fracture pattern is considered highly **unstable** because the fracture line runs from superomedial to inferolateral, leading to a high risk of **medial displacement** of the shaft. - **Long intramedullary (cephalomedullary) nails** are the preferred treatment as they provide superior **biomechanical stability** by acting as a load-sharing device with a shorter lever arm than plates, making them ideal for unstable intertrochanteric fractures, including reverse oblique. *Dynamic hip screw with anti-rotation screw* - A **Dynamic Hip Screw (DHS)** is generally contraindicated for reverse oblique patterns because the sliding mechanism allows the femoral shaft to shift **medially**, causing fixation failure due to the nature of the fracture line. - While effective for stable **intertrochanteric** fractures, using a DHS in this context often leads to **varus collapse** and implant cut-out. *Hemiarthroplasty* - This procedure involves replacing the femoral head and is typically reserved for **displaced intracapsular** hip fractures where there is a significant risk of **avascular necrosis** of the femoral head. - It is not indicated for **extracapsular** trochanteric fractures, which have an excellent blood supply and high potential for **bony healing** with internal fixation. *Cannulated screws* - Cannulated screws are specifically used for **undisplaced or minimally displaced intracapsular** neck of femur fractures, usually in younger, more active patients. - They do not provide the necessary **structural support** or rotational stability required to fix an **unstable extracapsular trochanteric reverse oblique fracture**. *Total hip replacement* - **Total hip replacement (THR)** is usually indicated for active older patients with **displaced intracapsular** fractures or those with pre-existing **osteoarthritis** of the hip. - Like hemiarthroplasty, it is not the standard of care for **extracapsular** trochanteric fractures, which are best managed with internal fixation to preserve the native hip joint.

Question 22: A 64-year-old man presents with a 3-week history of progressively worsening lower back pain. He describes the pain as constant, severe, and unrelieved by rest or analgesia. He has unintentional weight loss of 8kg over 2 months and reports fever and night sweats. He emigrated from Pakistan 15 years ago. Examination reveals tenderness over L3-L4 vertebrae. Temperature is 37.9°C. What is the most likely diagnosis?

A. Metastatic spinal disease
B. Spinal tuberculosis (Correct Answer)
C. Acute mechanical back pain
D. Ankylosing spondylitis
E. Spinal epidural abscess

Explanation: ***Spinal tuberculosis*** - Known as **Pott's disease**, it presents with **subacute or chronic back pain**, **fever**, **weight loss**, and **night sweats**, particularly in patients from **endemic regions** like Pakistan. - It commonly involves focal **vertebral tenderness** (e.g., L3-L4) due to anterior vertebral body destruction and can lead to **cold abscess** formation. *Metastatic spinal disease* - While it shares "red flags" like **weight loss** and **constant pain**, it is less likely than TB to present with **fever** and **night sweats** in this clinical context. - It typically targets the **pedicles** of the vertebrae rather than the vertebral bodies and disc spaces often seen in infective processes. *Acute mechanical back pain* - This condition usually follows a **physical trigger** or strain and lacks **constitutional symptoms** such as fever and weight loss. - The pain is typically **relieved by rest**, which is the opposite of the persistent, severe pain reported by this patient. *Ankylosing spondylitis* - This is an **inflammatory arthropathy** that typically presents in **younger patients** (usually <45 years) with pain that **improves with activity**. - It causes **morning stiffness** and is not associated with significant unintentional weight loss or acute fever. *Spinal epidural abscess* - Usually follows a more **acute clinical course** with a much **higher fever** and rapid progression of neurological deficits. - Most patients have specific risk factors such as **intravenous drug use**, recent spinal surgery, or severe **bacteremia** (often Staph aureus).

Question 23: An 81-year-old woman undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cementation, she develops sudden hypotension (BP 75/40 mmHg), desaturation (SpO₂ 88% on room air), and reduced end-tidal CO₂. What is the immediate management priority?

A. Administer intravenous adrenaline 1mg
B. Commence cardiopulmonary resuscitation
C. Increase inspired oxygen concentration and provide fluid resuscitation (Correct Answer)
D. Remove the prosthesis immediately
E. Administer intravenous hydrocortisone 200mg

Explanation: ***Increase inspired oxygen concentration and provide fluid resuscitation*** - The patient is presenting with **Bone Cement Implantation Syndrome (BCIS)**, characterized by sudden hypoxia, hypotension, and a drop in **end-tidal CO₂** during cementation. - Immediate management priority is ABC support: providing **100% oxygen** to combat hypoxia and aggressive **fluid resuscitation** to maintain cardiac output and blood pressure. *Administer intravenous adrenaline 1mg* - High-dose **adrenaline (1mg)** is reserved for cardiac arrest protocols and is not the first-line vasopressor for stable BCIS. - If hypotension persists, small incremental doses of **vasopressors** (like metaraminol or ephedrine) are preferred over full-dose adrenaline. *Commence cardiopulmonary resuscitation* - **Cardiopulmonary resuscitation (CPR)** is only indicated if the patient develops **cardiac arrest** (pulselessness). - Evaluation of the patient's BP (75/40) indicates a pulse is still present, requiring hemodynamics support rather than chest compressions. *Remove the prosthesis immediately* - Once cementation has occurred, removing the prosthesis is technically difficult and will not reverse the **systemic embolization** of marrow or air that has already triggered the syndrome. - Surgical focus should be on completing the procedure as quickly and safely as possible while the **anaesthetist** stabilizes the patient. *Administer intravenous hydrocortisone 200mg* - **Hydrocortisone** is a treatment for **anaphylaxis** or adrenal crisis, neither of which is the primary pathology in BCIS. - BCIS is an **embolic phenomenon** leading to pulmonary hypertension and right heart strain, not a Type I hypersensitivity reaction.

Question 24: A 46-year-old warehouse worker presents to his GP with a 14-week history of lower back pain. The pain is worse in the morning with stiffness lasting approximately 90 minutes. It improves with activity and is worse with rest. He has no red flag symptoms. Inflammatory markers show CRP 42 mg/L and ESR 38 mm/hr. Plain radiographs of the lumbar spine and sacroiliac joints are normal. What is the most appropriate next investigation?

A. HLA-B27 testing
B. MRI of the sacroiliac joints (Correct Answer)
C. CT scan of the lumbar spine
D. Bone scan
E. Repeat radiographs in 6 months

Explanation: ***MRI of the sacroiliac joints***- The patient's symptoms of **inflammatory back pain** (worse with rest, improves with activity, morning stiffness >30 minutes, duration >3 months) and elevated **CRP** and **ESR** strongly suggest axial spondyloarthritis.- Since plain radiographs are normal, **MRI of the sacroiliac joints** is the most appropriate next investigation as it is the gold standard for detecting early **sacroiliitis** (e.g., bone marrow oedema), which precedes structural changes visible on X-rays.*HLA-B27 testing*- While a positive **HLA-B27** is associated with axial spondyloarthritis, it is not diagnostic on its own, as many healthy individuals carry the gene, and some patients are HLA-B27 negative.- It's a supportive genetic marker, but not an imaging modality that can confirm active inflammation or sacroiliitis directly.*CT scan of the lumbar spine*- **CT scans** are useful for visualizing bony erosions and chronic structural damage but are less sensitive than MRI for detecting early active **inflammatory oedema**.- This modality also exposes the patient to **ionizing radiation**, making it less favorable than MRI for initial assessment of active inflammation.*Bone scan*- A **bone scan** is sensitive for detecting increased bone turnover but lacks the **specificity** to definitively diagnose axial spondyloarthritis.- It cannot reliably differentiate between various causes of increased uptake in the sacroiliac joints, such as infection, degenerative changes, or specific inflammatory arthropathies.*Repeat radiographs in 6 months*- Waiting for **radiographic progression** would significantly delay the diagnosis, as plain X-rays only show structural damage in later stages of axial spondyloarthritis.- Early diagnosis, facilitated by **MRI**, is crucial for initiating appropriate management and preventing irreversible structural damage and long-term disability.

Question 25: A 72-year-old man sustains a Garden III intracapsular neck of femur fracture. He has a past medical history of atrial fibrillation and is anticoagulated with apixaban. His surgery is delayed by 36 hours to allow for reversal of anticoagulation. What is the primary reason this surgical delay increases his risk of complications?

A. Increased risk of malunion due to muscle spasm causing further displacement
B. Development of fat embolism syndrome from bone marrow release
C. Increased risk of surgical site infection from prolonged immobilization
D. Higher mortality due to increased thromboembolic events and medical complications (Correct Answer)
E. Increased risk of avascular necrosis from progressive vascular compromise

Explanation: ***Higher mortality due to increased thromboembolic events and medical complications***- Surgical delay beyond **36 hours** is strongly associated with increased **mortality** and a higher incidence of medical complications like **pneumonia**, **pressure sores**, and **UTIs**.- Prolonged immobilization leads to a significantly higher risk of **venous thromboembolism (VTE)**, which is a major cause of post-operative morbidity in elderly hip fracture patients.*Increased risk of malunion due to muscle spasm causing further displacement*- **Malunion** is a long-term healing complication rather than an acute medical risk associated with the timing of surgery.- Neck of femur fractures are usually treated with **arthroplasty** or **internal fixation**, where the risk of malunion is independent of a 36-hour delay.*Development of fat embolism syndrome from bone marrow release*- **Fat embolism syndrome** is typically an early complication occurring shortly after the trauma or during **intraoperative manipulation** of the medullary canal.- It is not specifically categorized as the primary medical risk factor driven by the **pre-operative delay** of 36 hours.*Increased risk of surgical site infection from prolonged immobilization*- While prolonged hospital stays can increase exposure to **nosocomial pathogens**, immobilization itself is not the direct primary cause of **surgical site infections (SSI)**.- Systemic medical decline and **thromboembolic events** provide a much more significant contribution to the mortality associated with surgical delays.*Increased risk of avascular necrosis from progressive vascular compromise*- Although **avascular necrosis (AVN)** is a risk in **intracapsular fractures**, the primary damage to the blood supply occurs at the **time of injury**.- While early reduction is preferred, the increased **mortality rate** from medical complications is the more urgent systemic concern cited in surgical guidelines for these patients.

Question 26: A 67-year-old woman presents to the Emergency Department following a fall. She has a shortened and externally rotated leg. Radiographs confirm a displaced intracapsular neck of femur fracture. She has a history of chronic kidney disease stage 4 (eGFR 22 mL/min/1.73m²) and rheumatoid arthritis treated with methotrexate. She was independently mobile pre-injury. Which of the following is the most appropriate surgical management?

A. Uncemented hemiarthroplasty (Correct Answer)
B. Cemented hemiarthroplasty
C. Total hip replacement
D. Cannulated screw fixation
E. Dynamic hip screw fixation

Explanation: ***Uncemented hemiarthroplasty*** - In patients with **severe chronic kidney disease (Stage 4 CKD)**, there is an elevated risk of **Bone Cement Implantation Syndrome (BCIS)**, which uncemented fixation avoids. - For a **displaced intracapsular femoral neck fracture** in an independently mobile elderly patient, replacement (hemiarthroplasty) is required to prevent **avascular necrosis** and allow early mobilization. *Cemented hemiarthroplasty* - While often used in elderly patients, the patient's **Stage 4 CKD** significantly increases the risk of **cardiovascular collapse** due to **BCIS** during cement polymerization. - The systemic release of vasoactive substances from bone cement can cause profound **hypotension** and cardiorespiratory compromise, which is poorly tolerated in patients with **renal impairment**. *Total hip replacement* - This option is generally reserved for healthier, more active individuals with **high functional demand** or pre-existing hip osteoarthritis. - Given the patient's **CKD stage 4** and **rheumatoid arthritis**, a total hip replacement carries higher risks of surgical complexity, blood loss, **dislocation**, and periprosthetic infection compared to hemiarthroplasty. *Cannulated screw fixation* - This technique is primarily indicated for **undisplaced** or minimally displaced intracapsular fractures. - For a **displaced intracapsular fracture** in a 67-year-old, fixation has an unacceptably high rate of failure, including **non-union** and **avascular necrosis**. *Dynamic hip screw fixation* - A **Dynamic Hip Screw (DHS)** is the treatment of choice for **extracapsular (intertrochanteric)** fractures. - It is not suitable for an **intracapsular fracture** as it does not address the disrupted **blood supply** to the femoral head, leading to a high risk of **avascular necrosis**.

Question 27: A 68-year-old woman underwent total hip replacement for a displaced intracapsular neck of femur fracture 6 weeks ago. She now presents with sudden onset severe hip pain and inability to weight-bear. On examination, the affected leg is shortened, flexed, adducted and internally rotated. What is the most likely complication?

A. Periprosthetic fracture
B. Deep infection with prosthetic loosening
C. Posterior hip dislocation (Correct Answer)
D. Aseptic loosening of the acetabular component
E. Heterotopic ossification causing joint stiffness

Explanation: ***Posterior hip dislocation*** - The classic presentation of a **shortened**, **flexed**, **adducted**, and **internally rotated** leg is pathognomonic for a **posterior dislocation** following total hip replacement. - It is a common early complication occurring within the first few weeks to months, often triggered by movements like **leaning forward** while sitting or excessive hip flexion. *Periprosthetic fracture* - While it presents with pain and inability to weight-bear, it typically lacks the specific limb deformity of flexion, adduction, and internal rotation unless combined with dislocation. - Diagnosis is confirmed by **radiographic evidence** of a fracture around the implant, which is not primarily indicated by the described physical exam. *Deep infection with prosthetic loosening* - Typically presents with **systemic symptoms** (fever, malaise) and localized signs such as **warmth**, swelling, or a discharging sinus, not an acute mechanical deformity. - This complication is usually a **subacute or chronic process**, lacking the sudden onset of characteristic limb malposition. *Aseptic loosening of the acetabular component* - This is a long-term complication presenting as **gradual onset** mechanical pain, typically years after the initial surgery, not an acute event 6 weeks post-op. - It is caused by **wear debris** or mechanical failure and does not result in an acute flexed/rotated deformity of the limb. *Heterotopic ossification causing joint stiffness* - This condition involves **extraskeletal bone formation** in soft tissues, leading to a progressive loss of **range of motion** and stiffness over time. - It does not cause acute, severe pain with a **sudden change in limb position** or shortening as dramatically described in this case.

Question 28: A 66-year-old man with Paget's disease of bone affecting the proximal femur sustains a subtrochanteric fracture following minimal trauma. Radiographs show a transverse fracture pattern with lateral cortical thickening. He has been taking alendronic acid 70mg weekly for 8 years for osteoporosis. Which feature of the fracture most strongly suggests an atypical femoral fracture rather than a typical osteoporotic fracture?

A. The presence of underlying Paget's disease
B. The transverse fracture pattern with lateral cortical thickening (Correct Answer)
C. The subtrochanteric location
D. Association with prolonged bisphosphonate use
E. Occurrence following minimal trauma

Explanation: ***The transverse fracture pattern with lateral cortical thickening*** - These are **major radiographic criteria** for diagnosing **atypical femoral fractures (AFF)**, specifically the non-comminuted transverse or short oblique morphology. - **Lateral cortical thickening** (beaking or flaring) represents a localized stress reaction that is highly specific for a prodromal or impending atypical fracture, distinguishing it from typical osteoporotic fractures. *The presence of underlying Paget's disease* - While **Paget's disease** increases bone fragility and the risk of pathological fractures, it typically causes fractures on the convex surface of bowed bones, often with an oblique pattern. - The specific **transverse fracture pattern** and **lateral cortical thickening** described are more characteristic of AFFs, which are often related to bisphosphonate use, rather than a direct feature of Paget's disease itself. *The subtrochanteric location* - Although AFFs are primarily located in the **subtrochanteric region** and femoral shaft, this location alone is not diagnostic because **typical osteoporotic fractures** can also occur in this region. - The **fracture morphology** (transverse, simple) is a much stronger discriminator for AFFs than the anatomical location alone. *Association with prolonged bisphosphonate use* - Long-term use of **bisphosphonates** (like alendronic acid for >5 years) is a known **epidemiological risk factor** for AFFs, but it's not a direct radiological feature of the fracture itself. - Some patients can develop AFFs without bisphosphonate exposure, and conversely, many bisphosphonate users never develop AFFs, highlighting the importance of radiographic features for diagnosis. *Occurrence following minimal trauma* - Fractures following **minimal trauma** are characteristic of both **atypical femoral fractures** and **typical osteoporotic fractures**, making this feature non-specific for differentiating between the two. - The defining characteristic of an AFF is its specific radiographic appearance, not just the low-energy mechanism of injury.

Question 29: A 44-year-old woman with a 12-week history of inflammatory back pain has normal plain radiographs of the lumbar spine and sacroiliac joints. MRI of the sacroiliac joints shows bilateral bone marrow oedema in the subchondral bone. She tests positive for HLA-B27. Inflammatory markers show CRP 34 mg/L and ESR 42 mm/hr. What is the most appropriate next step in management?

A. Commence anti-TNF biological therapy immediately
B. Prescribe a non-steroidal anti-inflammatory drug and arrange rheumatology follow-up (Correct Answer)
C. Arrange for IL-17 inhibitor therapy
D. Commence methotrexate as first-line disease-modifying therapy
E. Prescribe long-term oral corticosteroids

Explanation: ***Prescribe a non-steroidal anti-inflammatory drug and arrange rheumatology follow-up*** - **NSAIDs** are the first-line treatment for **non-radiographic axial spondyloarthritis (nr-axSpA)** and should be trialed at the maximum tolerated dose for at least 2–4 weeks for symptomatic relief. - Referral to **rheumatology** is essential for diagnostic confirmation, disease monitoring, and guiding further treatment escalation if NSAIDs prove ineffective. *Commence anti-TNF biological therapy immediately* - **Anti-TNF therapy** is reserved for patients who have failed an adequate trial of at least two different **NSAIDs** and continue to have high disease activity (e.g., BASDAI ≥4). - Initiating biologics immediately bypasses standard treatment guidelines and algorithms for axial spondyloarthritis. *Arrange for IL-17 inhibitor therapy* - **IL-17 inhibitors** (e.g., secukinumab) are **biologic DMARDs** used in axial spondyloarthritis, typically after **NSAID failure** or as an alternative to anti-TNF agents. - Like anti-TNF agents, they are not indicated as the initial management step for a patient presenting with new onset inflammatory back pain. *Commence methotrexate as first-line disease-modifying therapy* - **Conventional synthetic DMARDs** like **methotrexate** have no proven efficacy in treating the **axial (spinal and sacroiliac joint)** symptoms of spondyloarthritis. - These medications are only utilized if there is significant **peripheral joint** involvement, which is not the primary presentation in this patient. *Prescribe long-term oral corticosteroids* - **Long-term oral corticosteroids** are not recommended in axial spondyloarthritis due to a lack of efficacy for spinal disease and a high risk of significant **adverse effects**. - While localized **corticosteroid injections** might be used for peripheral flares, systemic long-term use is not a standard of care for axial disease.

Question 30: A 73-year-old man undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cementation of the femoral component, the patient suddenly becomes hypotensive (BP 75/40 mmHg) with oxygen saturations dropping to 88% on high-flow oxygen. The anaesthetist notes increased pulmonary artery pressures on monitoring. What is the most likely underlying mechanism?

A. Anaphylactic reaction to bone cement methylmethacrylate
B. Embolisation of marrow fat and cement particles causing pulmonary vasoconstriction (Correct Answer)
C. Myocardial infarction precipitated by surgical stress
D. Haemorrhage from cement extrusion into the femoral vessels
E. Tension pneumothorax from positive pressure ventilation

Explanation: ***Embolisation of marrow fat and cement particles causing pulmonary vasoconstriction***- This patient is presenting with **Bone Cement Implantation Syndrome (BCIS)**, characterized by the hallmark triad of **hypoxia**, **hypotension**, and increased **pulmonary artery pressures** during cementation.- The mechanism involves high **intramedullary pressure** forcing fat, marrow, and cement into the venous system, causing **mechanical obstruction** and a chemical-mediated **pulmonary vasoconstriction** leading to right heart strain.*Anaphylactic reaction to bone cement methylmethacrylate*- While methylmethacrylate (MMA) can cause **vasodilation**, a true IgE-mediated **anaphylaxis** is extremely rare and typically presents with rash, bronchospasm, or angioedema.- BCIS is more definitively linked to the **embolic load** and the release of biochemical mediators rather than an allergic response.*Myocardial infarction precipitated by surgical stress*- Although surgical stress can trigger a **myocardial infarction (MI)**, it would not typically cause a sudden spike in **pulmonary artery pressure** specifically during the cementation phase.- ECG changes and cardiac enzymes would be required for diagnosis, and **hypoxia** is less likely to be the primary presenting feature compared to BCIS.*Haemorrhage from cement extrusion into the femoral vessels*- Cement extrusion could cause local **vascular injury**, but this would result in **hypovolemic shock** rather than immediate pulmonary hypertension and severe oxygen desaturation.- There is no clinical evidence of massive blood loss or a hematoma in the surgical field mentioned in this scenario.*Tension pneumothorax from positive pressure ventilation*- A **tension pneumothorax** causes hypotension and hypoxia, but it would typically present with **unilateral absent breath sounds** and tracheal deviation.- The temporal relationship specifically to **femoral cementation** makes an embolic phenomenon much more likely than a ventilation-induced barotrauma.

Question 31: A 59-year-old man with newly diagnosed multiple myeloma presents to the Emergency Department with a 2-week history of lower back pain and new onset faecal incontinence. He reports reduced perianal sensation but denies leg weakness. On examination, anal tone is reduced and perianal sensation is absent. What is the most critical time-dependent factor affecting prognosis in this patient?

A. Duration of symptoms before presentation
B. Time from presentation to MRI scanning
C. Time from symptom onset to surgical decompression (Correct Answer)
D. Timing of commencement of high-dose dexamethasone
E. Time to initiation of chemotherapy for the underlying malignancy

Explanation: ***Time from symptom onset to surgical decompression***- The prognosis for **neurological recovery**, particularly bladder and bowel function, is most critically linked to the **total duration** of nerve root compression.- Clinical evidence indicates that performing **emergency surgical decompression** within **24–48 hours** of the onset of autonomic symptoms like **faecal incontinence** significantly improves the chances of recovery.*Duration of symptoms before presentation*- While the delay before seeking help is part of the total time, it is not the **modifiable clinical factor** that defines the quality of modern emergency care standards.- Highlighting only the time before presentation ignores the critical role of **hospital efficiency** in achieving definitive management.*Time from presentation to MRI scanning*- Rapid **MRI imaging** is a crucial diagnostic step to confirm **Cauda Equina Syndrome**, but it is a means to an end rather than the prognostic endpoint itself.- Even if an MRI is obtained quickly, prognosis will be poor if there is a subsequent delay in moving the patient to the **operating theater**.*Timing of commencement of high-dose dexamethasone*- **High-dose dexamethasone** is essential adjunctive therapy to reduce **peritumoral oedema** in malignant spinal cord compression.- While steroids help stabilize the patient, they do not provide the **mechanical relief** of compression that is the primary determinant of long-term functional outcome.*Time to initiation of chemotherapy for the underlying malignancy*- **Chemotherapy** for Multiple Myeloma is vital for **systemic disease control**, but it acts far too slowly to rescue acutely compressed nerve roots.- In the setting of an acute neurologic emergency, **mechanical decompression** takes precedence over medical management of the primary hematological malignancy.

Question 32: A 78-year-old woman sustains an undisplaced Garden I intracapsular neck of femur fracture. She has good pre-injury mobility, normal cognitive function, and an ASA grade of 2. Following successful internal fixation with cannulated screws, at what time point is the risk of avascular necrosis of the femoral head highest?

A. Within the first 6 weeks post-operatively
B. At 3-6 months post-operatively
C. At 12-24 months post-operatively (Correct Answer)
D. At 3-5 years post-operatively
E. The risk remains constant throughout the post-operative period

Explanation: ***At 12-24 months post-operatively***- **Avascular necrosis (AVN)** of the femoral head typically follows a latent period, with clinical and radiological signs appearing most frequently between **1 to 2 years** post-injury.- This timeframe reflects the process of **creeping substitution**, where the ischemic bone undergoes remodeling and structural collapse after the initial vascular insult to the **medial circumflex femoral artery**.*Within the first 6 weeks post-operatively*- Complications at this early stage are usually related to **surgical site infections**, deep vein thrombosis, or acute mechanical **fixation failure**.- Bone **ischemia** occurs immediately at the time of fracture, but the necrotic process does not manifest radiographically or clinically within such a short window.*At 3-6 months post-operatively*- While **non-union** may become evident during this period, symptomatic **AVN** and femoral head collapse are less common this early in the recovery process.- Radiographs during this window may still appear normal despite the underlying vascular insult, as the **subchondral collapse** hasn't typically reached a detectable threshold.*At 3-5 years post-operatively*- While the risk of AVN can persist for several years, the peak incidence significantly **tapers off** after the 24-month mark.- Most cases are identified earlier due to the onset of **groin pain** and weight-bearing difficulties that prompt medical evaluation before the 3-year mark.*The risk remains constant throughout the post-operative period*- The risk of AVN follows a **temporal pattern** dictated by the blood supply's ability to recover or the bone's eventual collapse under physiological loads.- Once the femoral head has successfully **revascularized** or remodeled without collapse over the first few years, the risk of developing fracture-related AVN decreases significantly.

Question 33: A 51-year-old woman with a history of breast cancer treated 5 years ago presents with a 3-week history of progressive lower back pain. The pain is constant, severe, and disturbs her sleep. She has no neurological symptoms. Plain radiographs show a lytic lesion in the L3 vertebral body with >50% loss of vertebral height and involvement of the posterior elements. What is the most appropriate immediate management?

A. Commence oral analgesia and arrange outpatient oncology review
B. Urgent MRI whole spine and referral to spinal surgery (Correct Answer)
C. Arrange CT-guided biopsy of the lesion before any further management
D. Commence radiotherapy to the lumbar spine
E. Prescribe bisphosphonates and arrange outpatient follow-up

Explanation: ***Urgent MRI whole spine and referral to spinal surgery*** - The patient's history of breast cancer, combined with a **lytic vertebral lesion** exhibiting **>50% height loss** and **posterior element involvement**, indicates significant **biomechanical instability** and a high risk of impending **spinal cord compression**. - An urgent **MRI of the whole spine** is critical to fully assess the extent of neural involvement, and immediate **spinal surgical consultation** is necessary to consider stabilization. *Commence oral analgesia and arrange outpatient oncology review* - While pain control is important, a progressive, severe pain pattern with radiographic evidence of significant **vertebral destruction** requires more urgent assessment than an **outpatient review**. - Delaying definitive evaluation of **spinal instability** and potential neural compromise could lead to irreversible neurological deficits. *Arrange CT-guided biopsy of the lesion before any further management* - Although tissue diagnosis is generally necessary for cancer management, the patient's known history of breast cancer makes **metastatic disease** highly probable in this context. - Prioritizing a biopsy over urgent assessment for **spinal instability** and potential cord compression is inappropriate, as protecting the **spinal cord** is the immediate goal. *Commence radiotherapy to the lumbar spine* - **Radiotherapy** is effective for pain control and local tumor regression but does not address the immediate **structural instability** of a vertebra with significant collapse and posterior element involvement. - In cases of severe **vertebral destruction** with instability, **surgical stabilization** is often required before or in conjunction with radiotherapy to prevent neurological deterioration. *Prescribe bisphosphonates and arrange outpatient follow-up* - **Bisphosphonates** help reduce skeletal-related events in metastatic bone disease but do not provide immediate **mechanical support** for an acutely compromised and unstable vertebral body. - **Outpatient follow-up** is insufficient for a patient with severe pain and radiological signs of significant **vertebral collapse** and **instability**, which demands urgent inpatient management.

Question 34: A 67-year-old woman undergoes dynamic hip screw fixation for a stable two-part intertrochanteric fracture. Intraoperatively, the tip-apex distance is measured at 28mm on the final fluoroscopic images. What is the significance of this measurement?

A. It indicates optimal screw position with minimal risk of cutout
B. It is within acceptable limits but carries moderate risk of fixation failure (Correct Answer)
C. It indicates suboptimal positioning requiring screw repositioning
D. It predicts high risk of femoral head penetration requiring conversion to arthroplasty
E. It has no clinical relevance to postoperative outcomes

Explanation: ***It is within acceptable limits but carries moderate risk of fixation failure*** - A **Tip-Apex Distance (TAD)** greater than **25mm** is a well-established predictor of **lag screw cutout** and mechanical fixation failure. - At **28mm**, the risk of failure is higher than the optimal threshold (<25mm) but is often considered the upper limit of clinical acceptability, suggesting a moderate risk, especially with potentially reduced bone quality in a 67-year-old. *It indicates optimal screw position with minimal risk of cutout* - Optimal positioning is defined as a **TAD ≤25mm**, which correlates with a cutout rate of less than **1%**. - A measurement of 28mm increases the mechanical leverage on the femoral head, increasing the statistical likelihood of **screw migration** or cutout, thus not indicating minimal risk. *It indicates suboptimal positioning requiring screw repositioning* - Internal fixation is generally only repositioned if the TAD significantly exceeds **30mm** or if the screw is in a clearly unsafe position. - Repositioning at 28mm is often avoided to prevent creating **multiple tracks** in the femoral head, which could further weaken the bone and increase surgical morbidity. *It predicts high risk of femoral head penetration requiring conversion to arthroplasty* - TAD specifically predicts **cutout** (superior migration through the femoral head due to poor biomechanical purchase) rather than immediate **femoral head penetration** into the joint space. - Conversion to **arthroplasty** is typically a salvage procedure for failed fixation, not a direct intraoperative response to a TAD of 28mm. *It has no clinical relevance to postoperative outcomes* - The **Baumgaertner criteria** for TAD is a critically important and clinically significant predictor of success in **intertrochanteric fracture** repair. - Higher TAD values are directly linked to poor outcomes, including increased rates of **nonunion**, **malunion**, and the need for **revision surgery** due to mechanical collapse.

Question 35: A 43-year-old man presents with a 6-month history of lower back pain and morning stiffness lasting approximately 90 minutes. The pain improves with exercise but returns with rest. He has no history of trauma. Plain radiographs of the lumbar spine show no abnormality. What is the most appropriate next investigation to support the suspected diagnosis?

A. MRI sacroiliac joints (Correct Answer)
B. HLA-B27 testing
C. CT lumbar spine
D. Bone scan
E. Rheumatoid factor and anti-CCP antibodies

Explanation: ***MRI sacroiliac joints***- MRI is the most sensitive imaging modality for detecting early **inflammatory changes** such as **bone marrow edema** and synovitis, which define **non-radiographic axial spondyloarthritis**.- Since the plain radiographs are normal, an MRI is the gold standard next step to confirm **sacroiliitis** as part of the ASAS classification criteria.*HLA-B27 testing*- While **HLA-B27** is associated with axial spondyloarthritides, it is not a diagnostic test on its own because it is present in approximately **8% of the healthy population**.- It serves as a supportive marker rather than a definitive investigation for visualizing the active **pathological process** in the joints.*CT lumbar spine*- CT provides excellent detail of **bony erosions** and sclerosis but lacks the sensitivity to detect early **active inflammation** (marrow edema) seen on MRI.- It also exposes the patient to significant **ionizing radiation** without offering the diagnostic superiority of MRI in early disease stages.*Bone scan*- Bone scans have high sensitivity for increased bone turnover but demonstrate **low specificity** for inflammatory back pain and cannot distinguish between various types of arthritis.- It is generally not recommended in the routine diagnostic workup for **spondyloarthropathies** due to its poor anatomical resolution.*Rheumatoid factor and anti-CCP antibodies*- These markers are diagnostic for **Rheumatoid Arthritis**, which primarily affects **peripheral small joints** and is characterized by pain that worsens with activity.- Axial spondyloarthritides are typically **seronegative**, meaning these markers are expected to be negative in this clinical scenario.

Question 36: An 82-year-old man with severe cognitive impairment (Abbreviated Mental Test Score 4/10) sustains a displaced intracapsular neck of femur fracture. He was independently mobile with a walking frame prior to the fall. He has multiple comorbidities including chronic kidney disease stage 4 (eGFR 22ml/min/1.73m²), ischaemic heart disease, and atrial fibrillation. What is the most appropriate surgical management?

A. Uncemented hemiarthroplasty
B. Cemented hemiarthroplasty (Correct Answer)
C. Total hip replacement
D. Cannulated screw fixation
E. Conservative non-operative management

Explanation: ***Cemented hemiarthroplasty***- Per **NICE guidelines (CG124)** and evidence from the **WHiTE 5 trial**, cemented implants are preferred as they offer better **post-operative pain relief**, improved mobility, and lower mortality compared to uncemented options.- **Hemiarthroplasty** is more appropriate than Total Hip Replacement in patients with **severe cognitive impairment** (AMTS 4/10) to minimize the risk of post-operative **dislocation**.*Uncemented hemiarthroplasty*- Uncemented components are associated with a higher risk of **periprosthetic fractures** and increased persistent **thigh pain**.- Current orthopedic consensus favors **cemented fixation** even in the presence of comorbidities like stage 4 CKD, provided the anesthetic team manages **Bone Cement Implantation Syndrome** risks.*Total hip replacement*- While suitable for active patients, it is contraindicated here due to **cognitive impairment**, which significantly increases the risk of **dislocation** and poor compliance with post-op precautions.- Benefits of THR, such as reduced **acetabular erosion**, are less relevant in this elderly patient with a limited functional demand.*Cannulated screw fixation*- This approach is typically reserved for **undisplaced fractures** or very young patients where preserving the femoral head is a priority.- In **displaced intracapsular fractures** in the elderly, internal fixation has an unacceptably high rate of **non-union** and **avascular necrosis**.*Conservative non-operative management*- This is associated with a mortality rate exceeding **80% at one year** due to complications of prolonged immobility like **pressure sores** and **pneumonia**.- Since the patient was **independently mobile** prior to the fall, surgery is the best option to facilitate early mobilization and improve quality of life.

Question 37: A 56-year-old woman presents with a 4-month history of lower back pain and progressive bilateral leg weakness. She reports difficulty walking upstairs and recent episodes of urinary hesitancy. Neurological examination reveals bilateral lower limb weakness (power 4/5 in hip flexion and knee extension bilaterally), diminished ankle reflexes, and a post-void residual bladder volume of 250ml. What is the most appropriate immediate management?

A. Urgent MRI lumbar spine and referral to spinal surgery (Correct Answer)
B. Commence pregabalin and arrange outpatient physiotherapy
C. Prescribe high-dose non-steroidal anti-inflammatory drugs and review in 2 weeks
D. Arrange routine MRI lumbar spine within 6 weeks
E. Refer to urology for management of urinary retention

Explanation: ***Urgent MRI lumbar spine and referral to spinal surgery***- The patient presents with **red flag symptoms** for **Cauda Equina Syndrome (CES)**, including progressive bilateral leg weakness, diminished ankle reflexes, and bladder dysfunction (urinary hesitancy and high **post-void residual** volume). - **Immediate MRI** is essential to confirm the diagnosis and locate the compression, followed by urgent **surgical decompression** to prevent permanent neurological deficits. *Commence pregabalin and arrange outpatient physiotherapy* - These interventions are appropriate for managing chronic neuropathic pain or musculoskeletal issues, but not for an acute **neurological emergency** like suspected CES. - Delaying definitive diagnosis and treatment with conservative measures risks irreversible **spinal cord damage** and **bladder/bowel dysfunction**. *Prescribe high-dose non-steroidal anti-inflammatory drugs and review in 2 weeks* - **NSAIDs** are indicated for inflammatory or mechanical back pain, but they do not address the **nerve root compression** causing the neurological deficits. - A **2-week review** period is unacceptable given the rapid progression and potential for permanent harm in CES, which demands immediate action. *Arrange routine MRI lumbar spine within 6 weeks* - A **routine MRI** timeframe is for patients with stable symptoms or those being investigated for chronic conditions without acute neurological deterioration. - Suspected CES necessitates an **emergency MRI** (ideally within hours) to assess for spinal compression, as rapid intervention is critical for prognosis. *Refer to urology for management of urinary retention* - The **urinary retention** is a symptom of **neurogenic bladder dysfunction** due to **cauda equina compression**, not a primary urological problem. - Focusing solely on urological management without addressing the underlying spinal pathology would delay crucial intervention and lead to ongoing and potentially permanent neurological damage.

Question 38: A 74-year-old woman undergoes surgical fixation for a Garden II intracapsular neck of femur fracture with three cannulated screws inserted in an inverted triangle configuration. Post-operatively, she is noted to have a shortened leg length compared to the contralateral side despite satisfactory screw positioning on radiographs. What is the most likely mechanism responsible for this complication?

A. Inadequate screw length resulting in incomplete fracture reduction
B. Collapse at the fracture site due to loss of reduction during healing (Correct Answer)
C. Avascular necrosis of the femoral head causing segmental collapse
D. Posterior dislocation of the hip during positioning on the fracture table
E. Sciatic nerve palsy causing apparent leg shortening due to flexion deformity

Explanation: ***Collapse at the fracture site due to loss of reduction during healing*** - Intracapsular neck of femur fractures fixed with **cannulated screws** are designed to allow **controlled collapse** or impaction at the fracture site, which promotes healing by compression. - In elderly patients with **osteoporotic bone**, this biological and mechanical collapse can be more pronounced, leading to **secondary shortening** despite initially satisfactory reduction and screw placement. *Inadequate screw length resulting in incomplete fracture reduction* - The question states that **screw positioning** was satisfactory on radiographs, implying correct screw length and adequate initial reduction. - **Incomplete reduction** would be an intraoperative issue, typically detected immediately, not a post-operative complication developing later with otherwise good fixation. *Avascular necrosis of the femoral head causing segmental collapse* - **Avascular necrosis (AVN)** is a known long-term complication of femoral neck fractures, but its characteristic **segmental collapse** leading to shortening usually occurs **months to years** post-surgery, not in the immediate post-operative phase. - Early post-operative shortening, especially with good initial fixation, is more indicative of mechanical failure or impaction at the fracture site rather than the progression of AVN. *Posterior dislocation of the hip during positioning on the fracture table* - A **posterior hip dislocation** is an acute event, presenting with a distinct clinical picture of a shortened, **internally rotated**, and **adducted** limb, and would be immediately evident on post-operative imaging. - This mechanism is inconsistent with a situation where screw positioning is satisfactory and shortening is noted post-operatively as a complication of the fracture healing process. *Sciatic nerve palsy causing apparent leg shortening due to flexion deformity* - **Sciatic nerve palsy** causes neurological deficits like **foot drop** and sensory loss, and does not directly cause anatomical bone shortening at the fracture site. - While a severe **flexion deformity** can cause apparent shortening, it is a functional issue and not the primary mechanism for true anatomical leg length discrepancy after a well-fixed femoral neck fracture.

Question 39: A 69-year-old man presents to the Emergency Department with a 72-hour history of progressively worsening lower back pain. He describes the pain as severe and unrelenting, not relieved by rest or analgesia. He has a past medical history of chronic obstructive pulmonary disease for which he takes oral prednisolone 10mg daily. On examination, he is pyrexial at 38.2°C and has marked tenderness over the L3-L4 vertebrae. What is the most appropriate initial investigation to exclude the most likely diagnosis?

A. Plain radiographs of the lumbar spine
B. CT scan of the lumbar spine
C. MRI scan of the lumbar spine (Correct Answer)
D. Blood cultures and inflammatory markers
E. Bone scan with technetium-99m

Explanation: ***MRI scan of the lumbar spine*** - The patient's presentation with **progressively worsening, unrelenting lower back pain**, **pyrexia**, **localized tenderness**, and a history of **chronic oral prednisolone use (immunosuppression)** is highly suggestive of **spinal infection** (e.g., discitis or vertebral osteomyelitis). - **MRI with gadolinium contrast** is the **gold standard** investigation for diagnosing spinal infections, offering superior visualization of **vertebral marrow edema**, **disc space involvement**, and **epidural abscess formation**. *Plain radiographs of the lumbar spine* - Plain radiographs have **low sensitivity** for detecting early spinal infections, with changes typically appearing **2-4 weeks after symptom onset**. - They cannot adequately visualize **soft tissue involvement** or early inflammatory changes in the vertebral marrow, which are critical for diagnosis. *CT scan of the lumbar spine* - While a CT scan is excellent for demonstrating **cortical bone destruction**, it is **less sensitive than MRI** for detecting early inflammatory changes in the bone marrow and soft tissues, such as discitis or epidural collections. - It is often considered when MRI is contraindicated or for surgical planning after an MRI diagnosis. *Blood cultures and inflammatory markers* - **Blood cultures** and **inflammatory markers (ESR, CRP)** are crucial for identifying the causative organism and assessing disease activity, but they are **laboratory tests**, not imaging modalities. - They are **adjunctive investigations** that support the diagnosis of infection but cannot provide the necessary anatomical localization or confirm the extent of spinal involvement. *Bone scan with technetium-99m* - A **technetium-99m bone scan** has **high sensitivity** but **poor specificity** for spinal infection, as it can be positive in various conditions like degenerative disease, trauma, or tumors. - It also offers **inferior anatomical resolution** compared to MRI, making it difficult to precisely localize the infection or differentiate it from other pathologies.

Question 40: A 71-year-old woman sustains a neck of femur fracture following a fall. On examination, the affected leg is shortened and externally rotated. Radiographs confirm an extracapsular fracture. Which anatomical landmark best distinguishes intracapsular from extracapsular neck of femur fractures?

A. The greater trochanter
B. The intertrochanteric line anteriorly and intertrochanteric crest posteriorly (Correct Answer)
C. The lesser trochanter
D. The linea aspera
E. The subtrochanteric region

Explanation: ***The intertrochanteric line anteriorly and intertrochanteric crest posteriorly*** - The **hip joint capsule** attaches anteriorly to the **intertrochanteric line** and posteriorly to the **intertrochanteric crest**, which defines the boundary of the joint space. - Fractures occurring proximal to these landmarks are **intracapsular**, while those distal are **extracapsular**, with significant implications for **blood supply** to the femoral head. *The greater trochanter* - This is a prominent bony landmark and a site for **muscle attachments**, such as the gluteal muscles, but it does not define the capsular attachment. - Fractures involving the greater trochanter are by definition **extracapsular** but are not the primary landmark for distinguishing between neck fracture types. *The lesser trochanter* - The **lesser trochanter** is located on the posteromedial aspect of the proximal femur, serving as the insertion point for the **iliopsoas muscle**. - It is situated distal to the main capsular attachment and is more indicative of the subtrochanteric region rather than the precise intracapsular/extracapsular dividing line. *The linea aspera* - This is a rough longitudinal ridge located on the **posterior aspect of the femoral shaft**, providing attachment for various thigh muscles. - It is far too distal to the neck of the femur to be relevant in distinguishing between **intracapsular** and **extracapsular** neck fractures. *The subtrochanteric region* - This region refers to the area of the femur distal to the lesser trochanter, describing a specific type of **extracapsular fracture**. - While it is a fracture classification, it is not the anatomical landmark that delineates the boundary of the hip joint capsule itself.

Question 41: A 58-year-old man with metastatic prostate cancer presents with a 4-week history of progressive lower back pain and new onset bilateral lower limb weakness. MRI shows a pathological fracture of L2 vertebra with retropulsion of bone fragments causing significant spinal canal compromise and spinal cord compression. He has motor power 3/5 in both legs. What is the most appropriate initial management?

A. Urgent radiotherapy within 24 hours
B. High-dose dexamethasone and urgent radiotherapy
C. Immediate surgical decompression and stabilization (Correct Answer)
D. Percutaneous vertebroplasty
E. Conservative management with analgesia and mobilization

Explanation: ***Immediate surgical decompression and stabilization*** - **Surgical decompression** is the treatment of choice in cases of **metastatic spinal cord compression (MSCC)** where there is **spinal instability** or **mechanical compression** by bone fragments (retropulsion). - It is indicated for patients with a **prognosis >3 months** and functional deficits, as it provides immediate stabilization and better functional outcomes compared to radiotherapy alone in the setting of structural collapse. *Urgent radiotherapy within 24 hours* - **Radiotherapy** is primarily used for **radio-sensitive tumors** (e.g., lymphoma, myeloma) or cases where there is no mechanical instability/bone retropulsion. - While important, it cannot address the **mechanical instability** caused by a pathological fracture or provide the immediate structural support required in this patient. *High-dose dexamethasone and urgent radiotherapy* - **Dexamethasone** should be administered immediately to reduce **vasogenic edema**; however, it is an adjunctive therapy and not the definitive management for bone fragments. - Combining this with radiotherapy is insufficient for **unstable fractures**, as it fails to rectify the **spinal canal compromise** caused by the retropulsed bone. *Percutaneous vertebroplasty* - **Vertebroplasty** is used for pain relief in stable osteoporotic or malignant vertebral fractures without neurological compromise. - It is **contraindicated** in the presence of **spinal cord compression** or bone fragments in the spinal canal, as the cement could further compromise the cord. *Conservative management with analgesia and mobilization* - **Conservative management** is inappropriate for a patient with **progressive neurological deficits** (3/5 power) and mechanical cord compression. - **Spinal cord compression** is a medical emergency that requires active intervention to prevent permanent **paraplegia** and loss of autonomic function.

Question 42: A 67-year-old woman underwent total hip replacement for a displaced intracapsular neck of femur fracture 18 hours ago. She suddenly becomes confused and agitated, with worsening hypoxia (oxygen saturation 85% on 4L oxygen). Arterial blood gas shows: pH 7.32, PaO2 7.8 kPa, PaCO2 4.2 kPa, lactate 2.8 mmol/L. Chest radiograph shows bilateral diffuse infiltrates. What is the most likely diagnosis?

A. Aspiration pneumonia
B. Cardiogenic pulmonary oedema
C. Acute respiratory distress syndrome (ARDS) (Correct Answer)
D. Pulmonary embolism with infarction
E. Transfusion-related acute lung injury (TRALI)

Explanation: ***Acute respiratory distress syndrome (ARDS)*** - The patient's **acute severe hypoxemia**, **bilateral diffuse infiltrates** on chest X-ray, and confusion, occurring within 18 hours of **major orthopaedic surgery** for a hip fracture, are classic features of ARDS. - Severe trauma and orthopaedic surgery are significant risk factors, initiating a systemic inflammatory response that damages the **alveolar-capillary membrane**, leading to non-cardiogenic pulmonary oedema. *Aspiration pneumonia* - Typically presents with **localized infiltrates**, often in dependent lung segments like the **right lower lobe**, not the diffuse bilateral pattern seen here. - While post-operative patients are at risk, there is no mention of a witnessed aspiration event or specific risk factors like vomiting or impaired consciousness leading to aspiration. *Cardiogenic pulmonary oedema* - Although it causes **bilateral infiltrates** and hypoxemia, it usually presents with clinical signs of **fluid overload** or heart failure, such as **elevated JVP** or S3 gallop, which are absent in this case. - The context of major surgery and trauma points towards a **non-cardiogenic** cause of pulmonary oedema, unlike primary cardiac failure. *Pulmonary embolism with infarction* - A **pulmonary embolism** often presents with acute dyspnea and hypoxemia, but the chest X-ray is typically **normal** or shows focal changes like a Westermark sign or Hampton hump, not diffuse bilateral infiltrates. - While a possibility post-surgery, the widespread radiological changes are more indicative of a global lung injury like ARDS, which can be triggered by events such as **fat embolism syndrome**. *Transfusion-related acute lung injury (TRALI)* - TRALI is characterized by **acute hypoxemia** and **bilateral pulmonary infiltrates** that occur within 6 hours of a **blood product transfusion**. - The question does not specify a recent **blood transfusion**, and the 18-hour post-operative timeframe makes TRALI less likely unless the transfusion occurred much earlier with delayed onset of symptoms.

Question 43: A 42-year-old office worker presents with a 10-week history of lower back pain radiating down the posterior aspect of his right leg to the lateral aspect of his foot. He has reduced sensation over the lateral aspect of his foot and weakness of plantarflexion. Straight leg raise is positive at 40 degrees on the right. Which nerve root is most likely affected?

A. L3 nerve root
B. L4 nerve root
C. L5 nerve root
D. S1 nerve root (Correct Answer)
E. S2 nerve root

Explanation: ***S1 nerve root*** - S1 radiculopathy is characterized by **weakness in plantarflexion** (gastrocnemius/soleus) and loss of sensation over the **lateral aspect of the foot** and small toe. - It frequently results from an **L5/S1 disc herniation** and is associated with a **diminished ankle reflex**. *L3 nerve root* - Compression here typically results in sensory loss over the **anterior thigh** and weakness in **hip flexion** or knee extension. - It would not cause symptoms radiating to the lateral foot or affects on **plantarflexion**. *L4 nerve root* - L4 involvement presents with weakness in **knee extension** and a diminished **knee-jerk (patellar) reflex**. - Sensory loss is usually located on the **medial aspect of the leg** and foot, rather than the lateral side. *L5 nerve root* - L5 radiculopathy causes weakness in **big toe extension** (extensor hallucis longus) and **foot dorsiflexion**, leading to foot drop. - Sensory deficit is primarily found on the **dorsum of the foot** and the first web space between the first and second toes. *S2 nerve root* - Isolated S2 compression is rare and typically presents with sensory loss over the **posterior thigh** and popliteal fossa. - It is more commonly associated with **cauda equina syndrome**, involving bladder or bowel dysfunction rather than isolated plantarflexion weakness.

Question 44: A 77-year-old woman is being consented for cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. She asks about the risks of the procedure. According to the National Hip Fracture Database and published literature, what is the approximate 30-day mortality rate following surgical treatment of hip fracture in the UK?

A. 1-2%
B. 5-8% (Correct Answer)
C. 10-12%
D. 15-18%
E. 20-25%

Explanation: ***5-8%*** - According to data from the **National Hip Fracture Database (NHFD)**, the **30-day mortality** rate for hip fractures in the UK has settled within this range over recent years due to improved **orthogeriatric care**. - This statistic is essential for **informed consent** as it reflects the systemic frailty and perioperative risks associated with the elderly population. *1-2%* - This range is too low and is more representative of mortality for **elective** primary hip replacements in healthier cohorts. - **Hip fracture** patients are typically older with multiple **comorbidities**, resulting in significantly higher acute mortality. *10-12%* - Although historical rates were higher, modern **multidisciplinary management** has successfully reduced the average 30-day mortality below this level. - This percentage might be seen in specific **high-risk subgroups**, such as those with severe **cardiac failure** or high ASA grades, but not the national average. *15-18%* - Mortality this high is generally not observed within the first **30 days** post-surgery in contemporary UK practice. - These figures may align more with mortality rates at the **3-to-6-month** mark following a hip fracture. *20-25%* - This range is closer to the **one-year mortality** rate, which remains high at approximately **30%** for this patient demographic. - It overstates the immediate **perioperative risk** encountered within the first month of surgical intervention.

Question 45: A 54-year-old man with a 20-year history of ankylosing spondylitis presents to the Emergency Department after a minor fall. He reports severe neck pain and is protecting his cervical spine. He has no neurological deficit. What is the most appropriate initial imaging investigation?

A. MRI of the cervical spine
B. Plain radiographs of the cervical spine (3 views)
C. CT scan of the entire spine (Correct Answer)
D. Flexion-extension views of the cervical spine
E. Plain radiographs of the cervical spine followed by MRI if normal

Explanation: ***CT scan of the entire spine*** - In patients with **ankylosing spondylitis**, the fused and brittle **"bamboo spine"** is highly susceptible to **unstable fractures** even after minor trauma, requiring high-sensitivity imaging. - **CT scanning of the entire spine** is the preferred initial investigation because it can detect subtle fractures that may be **multiple or non-contiguous** across different spinal levels, which is crucial in AS. *Plain radiographs of the cervical spine (3 views)* - **Plain radiographs** have very low sensitivity in ankylosing spondylitis due to **overlapping ossified ligaments** and architectural distortion. - A "normal" radiograph cannot safely exclude a fracture in this patient population, often leading to **delayed diagnosis** and neurological catastrophe. *MRI of the cervical spine* - While **MRI** is superior for evaluating **spinal cord injury**, hematoma, or ligamentous tears, it is not the first-line modality for identifying acute bone cortex breaks. - MRI is typically reserved as a **secondary investigation** if the CT is negative but clinical suspicion or neurological deficits persist. *Flexion-extension views of the cervical spine* - These views are **strictly contraindicated** in the acute setting of suspected spinal fracture or instability. - Attempting forced motion in a brittle, potentially fractured spine can cause **displacement** and permanent **neurological damage**. *Plain radiographs of the cervical spine followed by MRI if normal* - Starting with radiographs is inappropriate as they are clinically unreliable for excluding fractures in a **rigid, osteoporotic spine**. - Relying on this sequence unnecessarily **delays definitive diagnosis** and may miss fractures at non-cervical levels that CT would have caught.

Question 46: A 68-year-old man underwent dynamic hip screw fixation for a stable two-part intertrochanteric fracture 4 months ago. He now presents with persistent groin pain on weight-bearing and difficulty mobilizing. Radiographs show the lag screw has migrated laterally through the femoral head with loss of fixation. What is the most likely mechanism responsible for this complication?

A. Infection leading to loosening of the implant
B. Excessive weight-bearing during the early post-operative period
C. Inadequate reduction with varus malposition at the fracture site (Correct Answer)
D. Osteoporosis causing continued collapse around the screw
E. Screw placed in the inferior portion of the femoral head

Explanation: ***Inadequate reduction with varus malposition at the fracture site***- **Varus malposition** places the lag screw in a more superior position relative to the femoral head, increasing the shear forces and the risk of **mechanical cut-out**.- Stable reduction is critical for the success of a **Dynamic Hip Screw (DHS)**, as it ensures that weight-bearing forces are transmitted through the bone rather than just the implant.*Infection leading to loosening of the implant*- **Implant loosening** due to infection usually presents with systemic symptoms, localized swelling, or **lucent lines** around the hardware on radiographs.- While infection causes bone resorption, it does not typically manifest as a specific lateral migration of the **lag screw** through the cortex without other signs of sepsis.*Excessive weight-bearing during the early post-operative period*- The **Dynamic Hip Screw (DHS)** is specifically designed to allow for **controlled compression** and collapse at the fracture site during weight-bearing.- While non-compliance can stress any hardware, it is rarely the primary cause of cut-out if the **Tip-Apex Distance (TAD)** and reduction are anatomically correct.*Osteoporosis causing continued collapse around the screw*- **Poor bone quality** (osteoporosis) certainly provides less resistance to screw migration, but it is considered a secondary risk factor compared to **surgical technique**.- Most fixation failures in osteoporotic bone are ultimately attributed to suboptimal hardware placement or poor **fracture reduction** rather than the bone quality alone.*Screw placed in the inferior portion of the femoral head*- Placement of the lag screw in the **inferior or central** portion of the femoral head is actually the recommended technique to minimize cut-out risk.- Contrastingly, **superior-posterior** placement is a known technical error that significantly increases the likelihood of the screw migrating through the femoral head.

Question 47: A 38-year-old woman presents to her GP with a 16-week history of lower back pain and early morning stiffness lasting more than 1 hour. She reports improvement with exercise. Plain radiographs of the lumbar spine and pelvis are normal. HLA-B27 is positive. What is the most appropriate next investigation to support the diagnosis of axial spondyloarthropathy?

A. Repeat plain radiographs in 3 months
B. CT scan of the sacroiliac joints
C. MRI of the sacroiliac joints with STIR sequences (Correct Answer)
D. Bone scintigraphy
E. Anti-CCP antibodies and rheumatoid factor

Explanation: ***MRI of the sacroiliac joints with STIR sequences*** - In the presence of normal radiographs but strong clinical suspicion of inflammatory back pain and **positive HLA-B27**, **MRI** is the most sensitive test to detect **active sacroiliitis**, specifically looking for **bone marrow oedema** in the sacroiliac joints. - This is crucial for diagnosing **non-radiographic axial spondyloarthropathy (nr-AxSpA)**, allowing for early intervention before structural damage is visible on X-ray. *Repeat plain radiographs in 3 months* - **Radiographic changes** in axial spondyloarthropathy, such as erosions or sclerosis of the sacroiliac joints, develop slowly and may take several years to become evident on plain films. - Repeating radiographs after only 3 months would be **premature** and is highly unlikely to show new findings, leading to a delay in definitive diagnosis and treatment. *CT scan of the sacroiliac joints* - While a **CT scan** provides excellent detailed images of **bone structure** and is superior to X-rays for detecting established chronic structural damage, it is less sensitive than MRI for **active inflammatory changes** like bone marrow oedema. - Furthermore, CT involves significant **ionizing radiation**, making it less suitable as a primary diagnostic tool for early inflammation, especially in younger patients, compared to MRI. *Bone scintigraphy* - **Bone scintigraphy**, or a bone scan, is a highly sensitive but **non-specific** imaging modality for detecting areas of increased bone turnover, which can occur in various conditions. - It has **poor specificity and sensitivity** for early sacroiliitis and is not recommended for diagnosing axial spondyloarthropathy due to its low diagnostic yield compared to MRI. *Anti-CCP antibodies and rheumatoid factor* - **Anti-CCP antibodies** and **rheumatoid factor (RF)** are serological markers primarily associated with the diagnosis of **rheumatoid arthritis (RA)**. - **Axial spondyloarthropathies** are typically **seronegative** for these autoantibodies, meaning they would not support the diagnosis of an axial spondyloarthropathy and would be an inappropriate investigation in this clinical context.

Question 48: An 80-year-old man presents 6 hours after a fall with a shortened and externally rotated right leg. Radiographs confirm a displaced intracapsular neck of femur fracture. He has atrial fibrillation (on warfarin with INR 3.2), chronic kidney disease stage 4, and a history of previous stroke with mild residual left-sided weakness. He lives in residential care and mobilizes 10 metres with a frame. What is the most appropriate management?

A. Delay surgery for 48 hours to correct coagulopathy with vitamin K
B. Proceed to theatre within 6 hours after prothrombin complex concentrate (Correct Answer)
C. Conservative management with analgesia and early mobilization
D. Arrange surgery within 36 hours after correcting INR to <1.5
E. Emergency surgery immediately regardless of INR

Explanation: ***Proceed to theatre within 6 hours after prothrombin complex concentrate*** - This patient has a **displaced intracapsular neck of femur fracture**, which requires urgent surgical intervention to prevent complications like **avascular necrosis** and achieve the best functional outcome. - **Prothrombin complex concentrate (PCC)** rapidly reverses the effects of **warfarin** (INR 3.2), allowing safe surgery within the critical **36-hour window** (ideally sooner for displaced fractures) while minimizing risks of hemorrhage. *Delay surgery for 48 hours to correct coagulopathy with vitamin K* - **Vitamin K** takes many hours (6-24 hours) to significantly reduce **INR**, and a 48-hour delay is excessive for a hip fracture, increasing the risk of **immobility-related complications** in an elderly patient. - Prolonged pre-operative delay contributes to higher rates of **venous thromboembolism**, **pressure ulcers**, and **chest infections**. *Conservative management with analgesia and early mobilization* - For a **displaced intracapsular hip fracture** in a patient with some baseline mobility, conservative management is associated with **high mortality rates** and poor functional outcomes. - Non-operative care often results in intractable pain, non-union, and a significant inability to return to pre-injury **mobility status**. *Arrange surgery within 36 hours after correcting INR to <1.5* - While the **36-hour window** is a standard target, merely

Question 49: A 52-year-old woman with a history of breast cancer treated 3 years ago presents with a 6-week history of thoracic back pain. The pain is constant, worse at night, and not relieved by analgesia. Plain radiographs show a lytic lesion in T8 vertebra with >50% loss of vertebral body height but no evidence of spinal cord compression on urgent MRI. What is the most appropriate Spinal Instability Neoplastic Score (SINS) classification for this lesion?

A. SINS 0-6: stable, requiring conservative management
B. SINS 7-12: potentially unstable, requiring specialist surgical assessment (Correct Answer)
C. SINS 13-18: unstable, requiring urgent surgical stabilization
D. SINS classification does not apply to metastatic lesions
E. SINS classification only applies to lesions with cord compression

Explanation: ***SINS 7-12: potentially unstable, requiring specialist surgical assessment***- The patient's **Spinal Instability Neoplastic Score (SINS)** is calculated as follows: **Tumor Location** (thoracic T8) 1 point, **Pain** (constant, worse at night) 3 points, **Bone Lesion Quality** (lytic) 2 points, and **Vertebral Body Collapse** (>50% height loss) 3 points. This totals **9 points**.- A SINS score between 7 and 12 indicates that the spine is **potentially unstable**, necessitating a **specialist spinal surgical consultation** to assess the need for stabilization or further intervention.*SINS 0-6: stable, requiring conservative management*- A score in this range denotes a **stable spine** where the risk of immediate structural failure or neurological compromise is considered low.- This patient's clinical and radiological findings, including significant **pain**, a **lytic lesion**, and **>50% vertebral collapse**, contribute to a score of 9, which exceeds the stable threshold.*SINS 13-18: unstable, requiring urgent surgical stabilization*- This score category signifies **frank instability**, where surgical intervention is almost always recommended to prevent or treat neurological deficits and maintain spinal integrity.- While the patient has significant factors indicating instability, a SINS score of 9 falls below the **definitely unstable** range of 13 or higher.*SINS classification does not apply to metastatic lesions*- This statement is incorrect. The **Spinal Instability Neoplastic Score (SINS)** was specifically developed and validated for assessing mechanical instability in patients with **vertebral metastases**.- It serves as a critical tool to help clinicians determine which patients with **neoplastic spinal disease** may benefit from surgical referral.*SINS classification only applies to lesions with cord compression*- This is incorrect. SINS is primarily designed to evaluate **mechanical stability** and the risk of **pathological fracture**, irrespective of the presence of **spinal cord compression**.- While cord compression is an important consideration for surgical urgency, the SINS system helps identify patients at risk of **spinal collapse** even without existing neurological deficits.

Question 50: A 75-year-old man sustained an undisplaced Garden I intracapsular neck of femur fracture 3 days ago and underwent internal fixation with three cannulated screws. On day 2 post-operatively, he develops sudden onset shortness of breath, confusion, and a petechial rash on his chest and conjunctivae. His oxygen saturation is 88% on room air. What is the most likely diagnosis?

A. Pulmonary embolism
B. Fat embolism syndrome (Correct Answer)
C. Bone cement implantation syndrome
D. Hospital-acquired pneumonia
E. Acute coronary syndrome

Explanation: ***Fat embolism syndrome*** - The classic triad of **respiratory distress** (shortness of breath, hypoxia), **neurological dysfunction** (confusion), and a **petechial rash** is characteristic of **fat embolism syndrome**. - This syndrome typically develops 24-72 hours after long bone fractures or orthopedic procedures, matching the **day 2 post-operative** presentation following a **femur fracture fixation**. The **petechial rash on the chest and conjunctivae** is highly specific. *Pulmonary embolism* - While **pulmonary embolism** causes sudden **shortness of breath** and **hypoxia**, it typically does not present with **confusion** and, crucially, a **petechial rash**. - It usually lacks the **neurological** and **dermatological** components that are prominent in this patient's presentation. *Bone cement implantation syndrome* - **Bone cement implantation syndrome** occurs **intraoperatively** or immediately post-operatively, during or shortly after the insertion of **cemented** prostheses. - This patient underwent **internal fixation with screws** (non-cemented) and symptoms developed **day 2 post-operatively**, making this diagnosis unlikely. *Hospital-acquired pneumonia* - **Hospital-acquired pneumonia** typically presents with signs of infection like **fever**, productive cough, and sometimes **purulent sputum**, which are not mentioned in this case. - The sudden onset of a **petechial rash** and acute confusion are not characteristic features of **pneumonia**. *Acute coronary syndrome* - **Acute coronary syndrome** primarily presents with **chest pain**, ECG changes, and possibly diaphoresis, not the distinct triad of **shortness of breath**, **confusion**, and a **petechial rash**. - While shortness of breath can be a symptom, the multisystem involvement in this patient points away from a primary cardiac event.

Question 51: A 48-year-old woman presents to the Emergency Department with a 12-hour history of severe lower back pain, bilateral leg weakness, and urinary retention requiring catheterization with 800ml residual volume. Examination reveals reduced power (3/5) in both legs, saddle anaesthesia, and absent ankle reflexes bilaterally. What is the maximum timeframe within which definitive surgical decompression should ideally be performed to optimize neurological recovery?

A. 6 hours from symptom onset
B. 24 hours from symptom onset
C. 48 hours from symptom onset (Correct Answer)
D. 72 hours from symptom onset
E. 1 week from symptom onset

Explanation: ***48 hours from symptom onset*** - For patients with **cauda equina syndrome (CES)**, performing surgical decompression within **48 hours** is the widely accepted critical window to maximize recovery of bladder, bowel, and motor function. - This patient presents with **CES-Retention (CESR)**, evidenced by **urinary retention** and **saddle anesthesia**, making urgent decompression within this timeframe vital to prevent permanent neurological deficits. *6 hours from symptom onset* - While some literature advocates for the fastest possible intervention, a **6-hour limit** is not standard practice and is often logistically unfeasible. - Decompression within **24-48 hours** has been shown in clinical studies to lead to similar outcomes compared to ultra-early intervention under 6 hours. *24 hours from symptom onset* - Many surgeons aim for surgery within **24 hours** to optimize the chances of recovery, but it is not defined as the absolute maximum cutoff for favorable outcomes. - Current guidelines emphasize that the most significant drop-off in **neurological prognosis** occurs if surgery is delayed beyond the **48-hour mark**. *72 hours from symptom onset* - Waiting until **72 hours** significantly increases the risk of irreversible **nerve root damage** and long-term disability. - Studies indicate that interventions performed after 48 hours are associated with much higher rates of persistent **incontinence** and sexual dysfunction. *1 week from symptom onset* - A delay of **one week** is far outside the therapeutic window for an acute surgical emergency like **cauda equina syndrome**. - By this stage, neurological deficits such as **lower motor neuron weakness** and loss of sphincter control are likely to be permanent and irreversible.

Question 52: A 72-year-old woman with a displaced Garden IV intracapsular neck of femur fracture is assessed for surgical management. She is normally independent, walks without aids, and has no significant past medical history. Her abbreviated mental test score is 9/10. Which surgical intervention is most appropriate?

A. Cannulated screw fixation
B. Dynamic hip screw
C. Total hip replacement (Correct Answer)
D. Cemented hemiarthroplasty
E. Uncemented hemiarthroplasty

Explanation: ***Total hip replacement*** - In active, medically fit elderly patients (like this 72-year-old independent woman with a good mental score) with a **displaced Garden IV intracapsular fracture**, **total hip replacement (THR)** is the preferred option. - THR provides **superior long-term functional outcomes** and significantly lower **revision rates** compared to hemiarthroplasty in this patient population. *Cannulated screw fixation* - This technique is generally reserved for **undisplaced (Garden I or II) intracapsular fractures** to preserve the femoral head. - It is unsuitable for **displaced Garden IV fractures** due to the high risk of **avascular necrosis** and non-union resulting from compromised blood supply. *Dynamic hip screw* - A **dynamic hip screw (DHS)** is the primary surgical treatment for **extracapsular trochanteric fractures**. - It is not indicated for **intracapsular neck of femur fractures**, which carry a distinct risk of avascular necrosis and require different management. *Cemented hemiarthroplasty* - While cemented hemiarthroplasty is a common treatment for displaced intracapsular fractures, it is typically chosen for patients with **lower functional demands**, significant comorbidities, or **cognitive impairment**. - For a highly functional and cognitively intact patient, **total hip replacement** offers better long-term results and quality of life compared to hemiarthroplasty. *Uncemented hemiarthroplasty* - **Uncemented prostheses** are generally not recommended for hip fractures in the elderly due to a higher incidence of **postoperative pain** and increased risk of **periprosthetic fractures**. - Current guidelines typically recommend **cemented prostheses** when performing hemiarthroplasty in this patient group to improve fixation and reduce pain.

Question 53: A 65-year-old man presents with a 3-week history of lower back pain. He describes the pain as constant, not relieved by rest, and rates it 8/10. He has lost 6 kg over the past 2 months and reports night sweats. Examination reveals tenderness over L3 vertebra. Temperature is 37.8°C. What is the most appropriate investigation to confirm the suspected diagnosis?

A. Plain radiographs of the lumbar spine
B. CT scan of the lumbar spine
C. MRI of the lumbar spine with gadolinium contrast (Correct Answer)
D. Bone scintigraphy
E. Full blood count and inflammatory markers

Explanation: ***MRI of the lumbar spine with gadolinium contrast*** - MRI with contrast is the gold standard for diagnosing **spinal infections (discitis/osteomyelitis)** or **malignancy**, as it provides superior soft tissue resolution and reveals early marrow changes. - It accurately detects complications such as **epidural abscesses** or spinal cord compression, which are critical in a patient presenting with high-intensity pain and **constitutional symptoms**. *Plain radiographs of the lumbar spine* - X-rays are often **insensitive** to early vertebral destruction and require at least 30-50% bone loss to show abnormalities. - They cannot reliably distinguish between malignancy, infection, or soft tissue pathology in the acute setting, especially with the presence of **red flag symptoms**. *CT scan of the lumbar spine* - CT is excellent for visualizing **bony architecture** and cortical destruction but lacks the sensitivity of MRI for early **marrow edema** or soft tissue infection. - It is generally reserved for patients with contraindications to MRI or those requiring CT-guided **biopsy**, not as the primary diagnostic tool in this case. *Bone scintigraphy* - This modality is highly sensitive for increased **bone turnover** but lacks the **specificity** to differentiate between infection, trauma, or metastatic disease. - It does not provide the detailed anatomical resolution necessary to evaluate the extent of **epidural involvement** or neural compression. *Full blood count and inflammatory markers* - While **ESR and CRP** are often elevated in infection and malignancy, they are **non-specific** and cannot localize the disease or confirm the diagnosis. - These tests are valuable for **monitoring treatment response** and indicating inflammation, rather than serving as the definitive primary diagnostic tool.

Question 54: A 70-year-old woman undergoes hemiarthroplasty for a displaced intracapsular neck of femur fracture. During the procedure, the surgeon must take care to preserve which anatomical structure that provides the majority of the blood supply to the femoral head in adults?

A. Artery of ligamentum teres from the obturator artery
B. Lateral circumflex femoral artery branches
C. Medial circumflex femoral artery via retinacular vessels (Correct Answer)
D. Nutrient artery from the femoral shaft
E. Superior gluteal artery perforating branches

Explanation: ***Medial circumflex femoral artery via retinacular vessels*** - The **medial circumflex femoral artery** (MCFA) provides the majority (70-80%) of the blood supply to the adult femoral head through its **retinacular branches**. - Damage to these critical vessels during a **displaced intracapsular femoral neck fracture** is the main reason for the high risk of **avascular necrosis** (AVN). *Artery of ligamentum teres from the obturator artery* - This artery plays a more significant role in **childhood**, but its contribution to the femoral head's blood supply in adults is very small, typically less than 10%. - It enters the head at the **fovea capitis** and is generally insufficient to sustain the femoral head alone after disruption of other major supplies. *Lateral circumflex femoral artery branches* - The **lateral circumflex femoral artery** (LCFA) mainly supplies the **greater trochanter**, vastus lateralis, and anterior hip joint capsule, with a minor contribution to the femoral head. - Its contribution to the direct vascularization of the femoral head is considerably less than that of the medial circumflex femoral artery. *Nutrient artery from the femoral shaft* - The **nutrient artery** system is primarily responsible for supplying the **diaphyseal cortex** and medullary cavity of the femur. - It does not significantly supply the femoral head, particularly as it would be disrupted by an **intracapsular neck fracture**. *Superior gluteal artery perforating branches* - The **superior gluteal artery** principally supplies the gluteal muscles and contributes to the **extracapsular arterial ring** around the hip. - It does not directly provide the major blood supply to the femoral head itself via retinacular vessels.

Question 55: A 74-year-old man sustains an intertrochanteric neck of femur fracture with posteromedial comminution and subtrochanteric extension. Pre-injury he was independently mobile with a frame. Radiographs show a reverse obliquity fracture pattern with lateral wall involvement. Which surgical implant is most appropriate for fixation?

A. Dynamic hip screw with single lag screw
B. Cannulated screws
C. Intramedullary cephalomedullary nail (Correct Answer)
D. Hemiarthroplasty
E. Dynamic hip screw with trochanteric stabilisation plate

Explanation: ***Intramedullary cephalomedullary nail*** - A **reverse obliquity pattern** and **subtrochanteric extension** characterize a highly unstable fracture, for which an **intramedullary cephalomedullary nail** is the gold standard treatment. - This implant provides superior **biomechanical stability** as a **load-sharing device**, effectively resisting **varus collapse** and medialization forces in these complex fracture types. *Dynamic hip screw with single lag screw* - This implant is **contraindicated** in **reverse obliquity** fractures because the fracture line allows the femoral shaft to displace laterally, leading to mechanical failure. - The significant **lateral wall involvement** in this case removes the necessary stable buttress for a DHS, greatly increasing the risk of **screw cut-out** or collapse. *Cannulated screws* - These are primarily indicated for **nondisplaced** or **minimally displaced intracapsular** (femoral neck) fractures, not for unstable extracapsular intertrochanteric injuries. - They lack the necessary **biomechanical strength** and stability to adequately fix a **comminuted intertrochanteric fracture** with subtrochanteric extension. *Hemiarthroplasty* - This procedure is typically reserved for **displaced intracapsular** femoral neck fractures in elderly patients, particularly those with poor bone quality or comorbidities. - It is generally not the treatment of choice for **intertrochanteric fractures**, especially with **subtrochanteric extension**, as it does not address the stability of the femoral shaft fragment effectively. *Dynamic hip screw with trochanteric stabilisation plate* - While the **trochanteric stabilization plate** enhances stability, this remains an **extramedullary device** and is biomechanically inferior to an intramedullary nail for **reverse obliquity** and **subtrochanteric extension** patterns. - It still experiences higher **bending moments** and is less effective at preventing varus collapse compared to a centrally placed intramedullary implant in these unstable fractures.

Question 56: A 52-year-old man with a 20-year history of chronic lower back pain presents with new onset severe pain radiating to both legs, worse in the left. He describes pain in the buttocks, thighs, and calves that worsens after walking 200 metres and is relieved by sitting or leaning forward. Straight leg raise is negative bilaterally. Peripheral pulses are palpable. What is the most likely underlying pathology?

A. Bilateral L5/S1 disc prolapse with nerve root compression
B. Peripheral vascular disease causing intermittent claudication
C. Lumbar spinal stenosis causing neurogenic claudication (Correct Answer)
D. Abdominal aortic aneurysm with peripheral embolisation
E. Cauda equina syndrome

Explanation: ***Lumbar spinal stenosis causing neurogenic claudication*** - The patient presents with classic **neurogenic claudication**, where leg pain is triggered by walking and specifically relieved by **sitting or leaning forward** (which increases spinal canal diameter). - A long history of chronic back pain suggests **degenerative changes** such as facet joint hypertrophy or ligamentum flavum thickening leading to canal narrowing. *Bilateral L5/S1 disc prolapse with nerve root compression* - **Acute disc prolapse** typically causes constant radicular pain that is usually worsened by coughing or straining and is often unilateral. - The **negative straight leg raise** test helps rule out acute nerve root irritation commonly seen in lumbar disc herniation. *Peripheral vascular disease causing intermittent claudication* - While both cause walking-induced pain, vascular claudication is relieved by simply **standing still**, whereas neurogenic claudication requires **sitting or flexion**. - The presence of **palpable peripheral pulses** strongly argues against significant peripheral vascular disease as the cause of these symptoms. *Abdominal aortic aneurysm with peripheral embolisation* - **Peripheral embolisation** (e.g., "blue toe syndrome") would typically present with acute pain, skin color changes, and potentially absent distal pulses. - This patient’s symptoms are chronic, related to posture, and occur bilaterally, making a **vascular emergency** or aneurysm less likely. *Cauda equina syndrome* - **Cauda equina syndrome** is a surgical emergency characterized by **saddle anesthesia**, bladder/bowel dysfunction, and severe neurological deficits. - While this patient has bilateral leg pain, the absence of **sphincter disturbance** and the postural nature of the relief point towards stenosis rather than acute compression.

Question 57: A 63-year-old woman with metastatic breast cancer presents with a 5-week history of progressive lower back pain. Over the past 48 hours, she has developed bilateral leg weakness and difficulty initiating micturition. On examination, power is 3/5 in both legs globally, with a sensory level at T10, reduced anal tone, and a palpable bladder. Urgent MRI confirms cord compression at T9 from vertebral metastasis with >50% canal compromise. What is the most appropriate initial pharmacological management while arranging definitive treatment?

A. Intravenous methylprednisolone 1g daily for 3 days
B. Oral dexamethasone 16mg daily (Correct Answer)
C. Intravenous mannitol 1g/kg
D. Oral prednisolone 40mg daily
E. Intravenous hydrocortisone 100mg four times daily

Explanation: ***Oral dexamethasone 16mg daily***- High-dose **dexamethasone** is the gold-standard initial treatment for **metastatic spinal cord compression (MSCC)** to reduce **vasogenic edema** and preserve neurological function.- A dose of **16mg daily** (often split as 8mg twice daily) is recommended as soon as the diagnosis is suspected to alleviate pressure before definitive **surgery or radiotherapy**.*Intravenous methylprednisolone 1g daily for 3 days*- This ultra-high dose protocol is typically reserved for **acute traumatic spinal cord injury** within a narrow time window, rather than neoplastic compression.- It carries a significantly higher risk of **gastrointestinal bleeding** and sepsis without proven superiority over dexamethasone for **malignant compression**.*Intravenous mannitol 1g/kg*- **Mannitol** is an osmotic diuretic used primarily to reduce **intracranial pressure** in cases of cerebral edema or head injury.- It has no established role in Managing **spinal cord compression** and would not address the inflammatory edema caused by the tumor.*Oral prednisolone 40mg daily*- This dose is insufficiently potent for the acute reduction of edema required in **MSCC**; dexamethasone is preferred due to its higher **glucocorticoid potency**.- **Prednisolone** also has higher **mineralocorticoid activity**, which can lead to unwanted fluid retention compared to dexamethasone.*Intravenous hydrocortisone 100mg four times daily*- **Hydrocortisone** is mainly used for **adrenal insufficiency** or acute asthma and lacks the strong anti-inflammatory profile needed for neuro-oncological emergencies.- The significant **mineralocorticoid effects** of high-dose hydrocortisone would cause excessive salt and water retention without providing adequate **neural decompression**.

Question 58: A 70-year-old woman sustains a displaced Garden III intracapsular neck of femur fracture. She was fully independent pre-injury, walks 2 miles daily, and has an AMTS of 10/10. She has well-controlled hypertension and hypothyroidism. The orthopaedic team is deciding between cemented hemiarthroplasty and total hip replacement. Which factor most strongly supports total hip replacement over hemiarthroplasty in this patient?

A. Age under 75 years
B. Good pre-injury functional status and cognitive function (Correct Answer)
C. Displaced intracapsular fracture pattern
D. Absence of significant medical comorbidities
E. Good mobility requiring 2-mile walking capacity

Explanation: ***Good pre-injury functional status and cognitive function*** - **Total hip replacement (THR)** is recommended by **NICE guidelines** for patients with displaced intracapsular fractures who were independently mobile, have no **cognitive impairment** (AMTS 10/10), and are medically fit. - THR provides superior **long-term functional outcomes** and lower revision rates compared to hemiarthroplasty in active patients who can tolerate the longer procedure. *Age under 75 years* - While younger age is often associated with higher activity, **chronological age** alone is not a strict cut-off for THR; clinical guidelines prioritize functional and mental status. - Some patients over 75 with excellent **physiological reserve** may still be better candidates for THR than younger patients with significant comorbidities. *Displaced intracapsular fracture pattern* - A **Garden III** or IV (displaced) fracture is an indication for **arthroplasty** rather than internal fixation, but it does not specify the type of arthroplasty. - Both **hemiarthroplasty** and THR are surgical options for displaced fractures; the choice between them depends on patient-specific factors like activity level. *Absence of significant medical comorbidities* - Being **medically fit for anesthesia** is a prerequisite for the longer THR procedure, but it is not the primary factor that dictates THR over hemiarthroplasty. - Many patients without comorbidities receive a **hemiarthroplasty** if they have low mobility demands or **cognitive decline**. *Good mobility requiring 2-mile walking capacity* - High mobility is a component of the selection criteria, but the decision is a composite of **independence**, **cognition**, and **fitness** rather than a specific walking distance. - **Walking 2 miles daily** confirms the patient's high functional baseline, supporting the need for a joint that can withstand higher mechanical demand.

Question 59: A 28-year-old man presents to the Emergency Department with sudden onset severe lower back pain and urinary retention following heavy lifting at the gym 18 hours ago. He reports bilateral leg paraesthesia and inability to pass urine for 12 hours. On examination, he has reduced perianal sensation, bilateral ankle weakness (4/5), and post-void residual volume of 800ml on bladder scan. MRI shows large L4-L5 central disc prolapse with cauda equina compression. He is listed for emergency decompression. What is the most important prognostic factor for neurological recovery?

A. Age of the patient
B. Size of disc prolapse on MRI
C. Duration of symptoms before surgical decompression (Correct Answer)
D. Severity of motor weakness at presentation
E. Presence of urinary retention versus urinary incontinence

Explanation: ***Duration of symptoms before surgical decompression*** - The **time to surgery** is the most critical prognostic factor, with decompression within **48 hours** (ideally <24 hours) significantly improving outcomes for bladder and bowel function. - Prolonged compression leads to **irreversible ischemic damage** to the nerve roots, meaning outcomes deteriorate rapidly the longer the surgery is delayed. *Age of the patient* - While younger age may assist in general rehabilitation, it is not a primary predictor of **neurological recovery** in acute cauda equina syndrome. - Surgical urgency remains the priority regardless of age to prevent **permanent neurological deficits**. *Size of disc prolapse on MRI* - Although a large canal occupancy is helpful for diagnosis, **radiological severity** of the disc prolapse does not correlate well with the degree of neurological recovery. - The **clinical presentation** and timing of intervention are far more clinically significant than the physical dimensions of the prolapsed disc. *Severity of motor weakness at presentation* - While initial motor deficits guide the urgency of care, even patients with **severe weakness** can experience significant recovery if decompressed quickly. - **Duration of compression** is a more reliable prognostic marker for long-term function than the baseline motor score. *Presence of urinary retention versus urinary incontinence* - Though **urinary retention (CESR)** often signals a more severe prognosis than incomplete symptoms (CESI), the timing of decompression still dictates the final functional outcome. - Classification into **CESI or CESR** helps categorize severity, but the delay to surgery is the ultimate determinant of whether bladder function returns.

Question 60: A 76-year-old woman undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. She has COPD (FEV1 45% predicted) and ischaemic heart disease. Intraoperatively, immediately after cement insertion, she develops severe hypotension (BP 70/40 mmHg), hypoxia (SpO2 82%), and bradycardia (HR 45/min). What is the underlying pathophysiology of this complication?

A. Type 1 hypersensitivity reaction to methyl methacrylate causing anaphylaxis
B. Pulmonary and systemic embolisation of cement, marrow contents, and air causing increased pulmonary vascular resistance (Correct Answer)
C. Direct myocardial toxicity from systemic absorption of cement monomer
D. Massive pulmonary embolism from dislodged deep vein thrombus
E. Haemorrhagic shock from intraoperative bleeding into the surgical site

Explanation: ***Pulmonary and systemic embolisation of cement, marrow contents, and air causing increased pulmonary vascular resistance*** - This clinical scenario describes **Bone Cement Implantation Syndrome (BCIS)**, an acute cardiorespiratory collapse occurring during cemented arthroplasty due to embolization. - **Pressurization of cement** into the intramedullary canal forces **fat globules, bone marrow, air, and cytotoxic cement monomers** into the venous system, causing **pulmonary vascular obstruction**, right heart strain, and subsequent systemic shock. *Type 1 hypersensitivity reaction to methyl methacrylate causing anaphylaxis* - While **methyl methacrylate** can cause allergic reactions, BCIS is primarily an **embolic and inflammatory response**, not a typical IgE-mediated anaphylaxis. - True **anaphylaxis** often includes cutaneous manifestations (e.g., urticaria, angioedema) or severe bronchospasm, which are not the defining features of this acute presentation. *Direct myocardial toxicity from systemic absorption of cement monomer* - Systemic absorption of **methyl methacrylate monomer** can contribute to **vasodilation** and direct myocardial depression, but it is considered a secondary mechanism in BCIS. - The immediate and dominant cause of severe hypotension and hypoxia in BCIS is the massive **pulmonary microembolism** and its hemodynamic consequences. *Massive pulmonary embolism from dislodged deep vein thrombus* - While a **venous thromboembolism (VTE)** is a risk in orthopedic surgery, the *immediate timing* of symptoms **after cement insertion** strongly points to **BCIS**, not a spontaneous DVT dislodgement. - BCIS is directly linked to the mechanical and biochemical events of the **cementing process**, differentiating it from a randomly dislodged pre-existing DVT. *Haemorrhagic shock from intraoperative bleeding into the surgical site* - **Haemorrhagic shock** from blood loss typically presents with hypotension and **compensatory tachycardia**, not the profound bradycardia observed in this case. - The acute onset of **hypoxia** and **bradycardia** immediately following cement application is inconsistent with typical hemorrhagic shock, which would usually have a more gradual onset and different vital sign patterns.

Question 61: A 67-year-old man with known prostate cancer presents with a 6-week history of progressively worsening thoracic back pain. The pain is constant, worse at night, and unrelieved by analgesia. On examination, there is tenderness over T8-T9 vertebrae, with normal power and sensation in the lower limbs. Plain radiographs show a lytic lesion in T9 vertebra. What is the most appropriate next step in management?

A. Commence oral bisphosphonate therapy and arrange outpatient oncology review
B. Arrange urgent whole spine MRI within 24 hours (Correct Answer)
C. Commence high-dose oral corticosteroids and arrange routine MRI
D. Refer for urgent radiotherapy to thoracic spine
E. Arrange CT-guided biopsy of the lesion

Explanation: ***Arrange urgent whole spine MRI within 24 hours*** - The patient presents with **red flags** for **Metastatic Spinal Cord Compression (MSCC)**, including known **prostate cancer**, progressively worsening back pain (constant, worse at night, unrelieved by analgesia), and a **lytic lesion** on radiograph. - **Urgent MRI of the whole spine** within 24 hours is the gold standard investigation to identify the degree of compression and check for **synchronous spinal metastases** before irreversible neurological damage occurs. *Commence oral bisphosphonate therapy and arrange outpatient oncology review* - While **bisphosphonates** are useful for reducing skeletal-related events and pain in bone metastases, they do nothing to prevent the acute neurological catastrophic risk of **spinal cord compression**. - An outpatient review results in a dangerous **diagnostic delay**, as suspected MSCC requires immediate emergency assessment and management to preserve motor and sensory function. *Commence high-dose oral corticosteroids and arrange routine MRI* - **High-dose oral corticosteroids** (e.g., Dexamethasone) should be initiated immediately upon *suspicion* of MSCC to reduce edema around the spinal cord, but this must be paired with an **urgent MRI**. - Delaying imaging by arranging a **routine MRI** increases the risk of the patient developing irreversible **neurological deficits** or even **paraplegia** while awaiting the scan. *Refer for urgent radiotherapy to thoracic spine* - **Radiotherapy** is a primary treatment modality for confirmed MSCC, but it cannot be safely or effectively prescribed without an **MRI** to precisely define the exact field and identify any other sites of compression. - Depending on the MRI findings, **surgical decompression** might be the preferred first-line treatment over radiotherapy for some patients, which can only be determined after comprehensive **MRI imaging**. *Arrange CT-guided biopsy of the lesion* - **CT-guided biopsy** is unnecessary and causes a delay in management because the patient already has a known primary diagnosis of **prostate cancer**, making the lytic lesion highly likely to be a metastasis. - The immediate priority is assessing for **thecal sac compression** and potential neurological compromise rather than histological confirmation of a clear metastatic process.

Question 62: A 73-year-old man undergoes dynamic hip screw fixation for a stable intertrochanteric neck of femur fracture. Post-operatively, he develops sudden onset dyspnoea and confusion 30 minutes after cementing. His oxygen saturation is 85% on room air, heart rate 118/min, blood pressure 95/60 mmHg. On examination, there is a petechial rash over his chest and conjunctival petechiae. What is the most likely diagnosis?

A. Pulmonary embolism
B. Bone cement implantation syndrome
C. Fat embolism syndrome (Correct Answer)
D. Myocardial infarction
E. Anaphylactic reaction

Explanation: ***Fat embolism syndrome***- This patient exhibits the classic clinical triad of **Fat Embolism Syndrome (FES)**: respiratory distress (dyspnoea/hypoxia), neurological changes (confusion), and a **petechial rash**.- The pathognomonic **petechial rash** on the chest and conjunctivae, combined with a history of **long bone fracture fixation**, distinguishes this from other causes of sudden cardiovascular collapse.*Pulmonary embolism*- While it causes sudden **dyspnoea**, hypoxia, and tachycardia, it typically presents later in the postoperative course rather than immediate intraoperative or early postoperative phases.- Crucially, it does not present with a **petechial rash** or the acute cerebral involvement seen in this case.*Bone cement implantation syndrome*- This occurs specifically during **cementing** and involves hypoxia and hypotension due to the release of methylmethacrylate, which increases pulmonary vascular resistance.- Although timing is suggestive, it does not account for the **petechial rash** or delayed confusion characteristic of fat emboli entering the systemic circulation.*Myocardial infarction*- An acute **myocardial infarction** could lead to hypotension and dyspnoea (from pulmonary edema), but it is less likely given the surgical context and clinical signs.- It would not cause a **petechial distribution** or primary neurological symptoms without global hypoperfusion.*Anaphylactic reaction*- Anaphylaxis typically presents with **urticaria**, angioedema, or wheezing rather than a petechial rash and confusion.- While it can cause rapid cardiovascular collapse, the specific **post-fracture triad** strongly favors fat embolism syndrome.

Question 63: A 55-year-old man presents to his GP with a 12-week history of lower back pain and morning stiffness lasting 3 hours. The pain improves with exercise. He reports alternating buttock pain. On examination, Schober's test shows 3cm expansion (normal >5cm). Inflammatory markers show CRP 28 mg/L and ESR 35 mm/hr. What is the most appropriate initial investigation to establish the diagnosis?

A. Plain radiographs of lumbar spine and pelvis
B. MRI of sacroiliac joints and spine (Correct Answer)
C. HLA-B27 testing
D. CT of lumbar spine
E. Bone scan

Explanation: ***MRI of sacroiliac joints and spine*** - **MRI** is the gold standard for early diagnosis because it can detect **bone marrow oedema** and active inflammatory changes years before they appear on X-rays. - Given the clinical presentation of **inflammatory back pain** and an abnormal **Schober's test**, MRI is the most sensitive initial step to assess for **sacroiliitis**. *Plain radiographs of lumbar spine and pelvis* - X-rays may be **normal in early disease** as structural damage like syndesmophytes or fusion can take 5-10 years to become visible. - While traditionally used, they lack the sensitivity to detect **non-radiographic axial spondyloarthritis**, delaying potential treatment. *HLA-B27 testing* - **HLA-B27** is associated with the condition but is not diagnostic on its own, as it is present in approximately 8% of the **general healthy population**. - A positive result supports the diagnosis but does not provide **visual confirmation** of active inflammation or joint damage. *CT of lumbar spine* - CT provides excellent **bony detail** for chronic changes but is unable to visualize the **soft tissue edema** characteristic of early inflammation. - It involves a significantly **higher radiation dose** compared to other modalities and is generally not the first-line choice for spondyloarthropathies. *Bone scan* - Bone scans are highly sensitive but lack the **specificity** required to distinguish between different types of inflammatory or degenerative spinal conditions. - They do not provide the detailed **anatomical visualization** of the sacroiliac joints necessary to confirm a diagnosis of ankylosing spondylitis.

Question 64: An 80-year-old woman sustains a Garden II undisplaced intracapsular neck of femur fracture. She is fully mobile pre-injury with a walking stick, living independently. She has atrial fibrillation, hypertension, and chronic kidney disease stage 3. Her abbreviated mental test score is 9/10. What is the most appropriate surgical management?

A. Cemented hemiarthroplasty
B. Uncemented hemiarthroplasty
C. Total hip replacement
D. Internal fixation with cannulated screws (Correct Answer)
E. Non-operative management with early mobilisation

Explanation: ***Internal fixation with cannulated screws*** - For **Garden I and II undisplaced intracapsular fractures**, **internal fixation** (commonly with cannulated screws) is the preferred treatment to preserve the natural femoral head. - This procedure is less invasive, with lower **operative time** and **blood loss**, which is advantageous for an 80-year-old patient with significant **comorbidities**. *Cemented hemiarthroplasty* - This is primarily indicated for **displaced intracapsular fractures** (Garden III and IV) in elderly patients, especially those with limited mobility or cognitive impairment. - While suitable for the elderly, it is a more invasive procedure than internal fixation and not the first choice for an **undisplaced fracture**. *Uncemented hemiarthroplasty* - Generally avoided in older patients due to a higher risk of **intra-operative fractures** and poor long-term outcomes compared to cemented fixation. - **NICE guidelines** recommend **cemented implants** when arthroplasty is indicated for hip fractures in the elderly. *Total hip replacement* - Reserved for **displaced intracapsular fractures** in active, cognitively intact patients with a good life expectancy, often to prevent future revision. - Although the patient is fit and cognitively intact, her fracture is **undisplaced**, making joint-preserving **internal fixation** the more appropriate initial option. *Non-operative management with early mobilisation* - This approach is typically reserved for patients who are **non-ambulatory** before the injury or those with **terminal illness** and are too medically unstable for any surgical intervention. - It carries a high risk of **non-union**, malunion, and prolonged pain, which would compromise this patient's **pre-injury independence** and quality of life.

Question 65: A 69-year-old woman with rheumatoid arthritis presents with a 4-week history of worsening lower back pain and progressive bilateral leg weakness. She has been taking prednisolone 15mg daily for the past 10 years. On examination, she has reduced power bilaterally in hip flexion (3/5) and knee extension (3/5), with saddle anaesthesia. What is the most appropriate immediate management?

A. Commence analgesia and physiotherapy referral
B. Arrange urgent MRI spine and immediate neurosurgical referral (Correct Answer)
C. Arrange routine MRI spine within 2 weeks
D. Commence oral bisphosphonate therapy
E. Increase prednisolone dose to 30mg daily

Explanation: ***Arrange urgent MRI spine and immediate neurosurgical referral*** - The patient presents with classic features of **Cauda Equina Syndrome (CES)**, including **saddle anaesthesia**, progressive **bilateral leg weakness**, and worsening back pain. - This is a **neurosurgical emergency** requiring urgent diagnostic imaging (MRI) and prompt surgical decompression to prevent permanent neurological deficits. *Commence analgesia and physiotherapy referral* - **Physiotherapy** is contraindicated in acute **neurological compromise** due to potential spinal cord or cauda equina compression. - Relying solely on **analgesia** would significantly delay definitive treatment, risking **irreversible nerve damage** and permanent disability. *Arrange routine MRI spine within 2 weeks* - A routine MRI is inappropriate for suspected **Cauda Equina Syndrome**, which demands **immediate imaging** to confirm the diagnosis and identify the level of compression. - Delays beyond **24-48 hours** can significantly worsen prognosis and lead to permanent neurological deficits such as **bowel and bladder dysfunction**. *Commence oral bisphosphonate therapy* - While chronic **prednisolone** use increases the risk of **osteoporosis** and vertebral fractures, bisphosphonates do not address the acute neurological emergency of cauda equina compression. - This therapy is for **long-term bone density management** and offers no immediate benefit for nerve root decompression. *Increase prednisolone dose to 30mg daily* - Increasing steroid dosage will not resolve the **mechanical compression** of the cauda equina and could exacerbate existing **osteoporosis** or mask a potential infectious cause like an epidural abscess. - Steroids are not a treatment for **structural compression** of nerve roots, which requires urgent surgical intervention.

Question 66: A 42-year-old woman presents with a 5-week history of lower back pain that radiates down her right leg to the lateral aspect of her foot. She reports numbness over the dorsum of her foot and difficulty walking on her heels. Straight leg raise is positive at 40 degrees on the right. Which nerve root is most likely affected?

A. L3
B. L4
C. L5 (Correct Answer)
D. S1
E. S2

Explanation: ***L5***- The patient's presentation with **numbness over the dorsum of the foot**, difficulty walking on her **heels** (indicating weakness in foot dorsiflexion), and pain radiating to the **lateral aspect of her foot** are classic symptoms of **L5 radiculopathy**.- A positive **straight leg raise** test further supports nerve root compression, often seen with lumbar disc herniation affecting the L5 root, typically at the **L4-L5 level**.*L3*- L3 radiculopathy typically presents with sensory loss over the **anterior thigh** and the medial aspect of the knee.- Motor weakness primarily involves **hip flexion** and **knee extension**, not foot dorsiflexion.*L4*- L4 nerve root compression is characterized by sensory deficits over the **medial leg** and medial malleolus, not the dorsum of the foot.- It often results in weakness of **knee extension** and a diminished **patellar reflex**.*S1*- S1 radiculopathy is typically associated with weakness in **plantar flexion**, leading to difficulty with **toe walking**.- Sensory loss is primarily over the **lateral aspect of the foot** and small toe, and the **Achilles reflex** is usually diminished.*S2*- S2 nerve root compression is less common and primarily affects sensation over the **posterior thigh** and popliteal fossa.- It does not typically cause the specific motor weakness in **heel walking** or the sensory distribution over the dorsal foot seen in this patient.

Question 67: A 75-year-old man presents to the Emergency Department following a fall. He has pain in his right hip and cannot weight-bear. On examination, the right leg appears shortened and externally rotated. Radiographs confirm a neck of femur fracture. What anatomical landmark distinguishes intracapsular from extracapsular neck of femur fractures?

A. Lesser trochanter
B. Greater trochanter
C. Intertrochanteric line anteriorly and intertrochanteric crest posteriorly (Correct Answer)
D. Femoral shaft
E. Subtrochanteric region

Explanation: ***Intertrochanteric line anteriorly and intertrochanteric crest posteriorly*** - These landmarks represent the **distal attachment** of the **hip joint capsule**; fractures proximal to these lines are considered **intracapsular**. - This distinction is critical because intracapsular fractures risk disrupting the **medial circumflex femoral artery**, leading to **avascular necrosis**. *Lesser trochanter* - This is a site of attachment for the **iliopsoas muscle** and is located distal to the capsule, making it a feature of **extracapsular** fractures. - Isolated fractures here are rare and usually occur due to **avulsion injuries** in younger patients or metabolic bone disease. *Greater trochanter* - The greater trochanter serves as an attachment point for the **gluteus medius** and minimus and is located outside the synovial joint capsule. - Fractures involving this area are classified as **extracapsular** and generally have a better blood supply for healing compared to neck fractures. *Femoral shaft* - This region starts distal to the **subtrochanteric area** and is entirely unrelated to the hip joint capsule boundaries. - Injuries here are classified as **femoral shaft fractures** and are managed with different surgical techniques like **intramedullary nailing**. *Subtrochanteric region* - Defined as the area within **5cm distal** to the lesser trochanter, which is well below the capsular attachment points. - Fractures in this zone are **extracapsular** and are subjected to high mechanical stresses from surrounding musculature.

Question 68: A 68-year-old woman sustains an intracapsular neck of femur fracture following a fall. Which artery provides the majority of the blood supply to the femoral head in adults and is most commonly disrupted in displaced intracapsular fractures?

A. Lateral circumflex femoral artery
B. Medial circumflex femoral artery (Correct Answer)
C. Artery of ligamentum teres
D. Inferior gluteal artery
E. Obturator artery

Explanation: ***Medial circumflex femoral artery*** - This artery provides the **majority (60-80%)** of the blood supply to the adult femoral head via its **retinacular branches**. - Because these branches are **intracapsular** and closely applied to the femoral neck, they are frequently torn in **displaced fractures**, leading to high rates of **avascular necrosis**. *Lateral circumflex femoral artery* - This artery mainly supplies the **greater trochanter** and the soft tissues of the lateral thigh, contributing minimally to the femoral head. - While it participates in the **cruciate anastomosis**, its role in maintaining femoral head viability is significantly less than that of the medial circumflex. *Artery of ligamentum teres* - This artery is a branch of the **obturator artery** and provides only about **10-20%** of the blood supply to the femoral head in adults. - It is generally **insufficient** to prevent ischemic death of the femoral head if the main retinacular supply is lost due to a fracture. *Inferior gluteal artery* - The inferior gluteal artery primarily supplies the **gluteus maximus** muscle and the posterior pelvic region. - While it contributes to the **trochanteric anastomosis**, it is not a direct or significant source of blood for the **proximal head of the femur**. *Obturator artery* - The obturator artery gives rise to the **artery of the ligamentum teres**, which is only a minor contributor to adult femoral vascularity. - It primarily supplies the **muscles of the medial compartment** of the thigh and the pelvic wall rather than the bone of the femoral head.

Question 69: A 71-year-old man sustains a subtrochanteric femur fracture 3cm below the lesser trochanter following a fall down stairs. Radiographs show a transverse fracture pattern with a medial spike of cortex. He has a history of osteoporosis and has been taking alendronate 70mg weekly for 8 years with good compliance. What is the most likely underlying aetiology of this fracture?

A. Pathological fracture through metastatic deposit
B. Stress fracture from undiagnosed Paget's disease
C. Atypical femoral fracture related to long-term bisphosphonate therapy (Correct Answer)
D. Typical osteoporotic fragility fracture
E. Insufficiency fracture from vitamin D deficiency

Explanation: ***Atypical femoral fracture related to long-term bisphosphonate therapy***- This patient's fracture exhibits classic **atypical femoral fracture (AFF)** features, including a **subtrochanteric location**, **transverse fracture pattern**, and the characteristic **medial spike** of cortex.- Long-term use of **bisphosphonates** (specifically >5 years) can lead to oversuppression of **bone remodeling**, causing the accumulation of microdamage and specialized stress fractures.*Pathological fracture through metastatic deposit*- While metastases often occur in the proximal femur, they typically present with **lytic or blastic lesions** on imaging rather than a clean transverse fracture with a medial spike.- There is no mention of a primary malignancy or system symptoms that would lead toward a **neoplastic** etiology.*Stress fracture from undiagnosed Paget's disease*- Paget's disease typically causes **cortical thickening**, **coarse trabeculae**, and bone enlargement, which are not described in this radiographic presentation.- While Paget's can result in fractures, they usually occur in bones that show characteristic **osteoblastic and osteoclastic** remodeling abnormalities.*Typical osteoporotic fragility fracture*- Osteoporotic fragility fractures of the hip usually involve the **femoral neck** or **intertrochanteric region** and often have a spiral or oblique configuration.- The **transverse pattern** and specific subtrochanteric location are specifically defining features of **atypical** fractures rather than standard fragility fractures.*Insufficiency fracture from vitamin D deficiency*- While **vitamin D deficiency** (osteomalacia) can lead to Looser's zones or insufficiency fractures, these are typically bilateral and located in the **femoral neck** or pubic rami.- This fracture's morphological features and the strong correlation with **8 years of alendronate** use make AFF the most probable diagnosis.

Question 70: A 39-year-old woman presents with a 16-week history of lower back pain and significant morning stiffness. She reports the pain alternates between both buttocks and improves throughout the day with activity. Examination shows reduced lumbar spine flexion. Blood tests show ESR 38 mm/hr, CRP 22 mg/L, normal ANA, negative rheumatoid factor, and HLA-B27 positive. MRI pelvis shows bilateral bone marrow oedema in the sacroiliac joints. What is the most appropriate initial pharmacological management?

A. High-dose non-steroidal anti-inflammatory drug (NSAID) continuously (Correct Answer)
B. Anti-TNF biologic therapy (adalimumab)
C. Bisphosphonate therapy (alendronate)
D. Oral prednisolone 15mg daily with calcium and vitamin D
E. Disease-modifying antirheumatic drug (methotrexate)

Explanation: ***High-dose non-steroidal anti-inflammatory drug (NSAID) continuously***- **NSAIDs** are the first-line pharmacological treatment for **axial spondyloarthritis** and should be used at the maximum tolerated dose to reduce inflammation and pain.- Unlike other forms of arthritis, **continuous use** of NSAIDs in axial disease is preferred over on-demand use as it may potentially slow **radiographic progression**.*Anti-TNF biologic therapy (adalimumab)*- These are highly effective agents restricted to **second-line therapy** for patients who have failed at least two different **NSAIDs** over a 4-week period.- They are indicated only if disease activity remains high, typically measured by a **BASDAI score** of 4 or more.*Bisphosphonate therapy (alendronate)*- This class of medication is used to treat **osteoporosis** and has no role in managing the primary inflammatory symptoms of **ankylosing spondylitis**.- While patients with chronic inflammation are at higher risk for bone loss, it is not an **initial management** strategy for back pain.*Oral prednisolone 15mg daily with calcium and vitamin D*- **Systemic corticosteroids** are generally avoided in axial spondyloarthritis because they have shown **limited efficacy** for spinal disease.- Long-term use of oral steroids carries significant risks, including **osteoporosis** and metabolic complications, without improving long-term outcomes in this condition.*Disease-modifying antirheumatic drug (methotrexate)*- Conventional **DMARDs** like methotrexate or sulfasalazine are ineffective for **axial (spinal) disease** and are not recommended for isolated sacroiliitis.- These agents are only considered in cases where there is significant **peripheral joint involvement** accompanying the axial symptoms.

Question 71: A 76-year-old woman sustains a displaced intracapsular neck of femur fracture and undergoes cemented hemiarthroplasty. At 18 months post-operatively, she presents with progressive hip pain, especially on weight-bearing. Radiographs show progressive acetabular wear with protrusio acetabuli and superior migration of the prosthetic head. What is the most appropriate management strategy at this stage?

A. Revision to total hip replacement with acetabular component (Correct Answer)
B. Conservative management with analgesia and walking aids
C. Excision arthroplasty (Girdlestone procedure)
D. Revision to uncemented hemiarthroplasty
E. Hip arthrodesis

Explanation: ***Revision to total hip replacement with acetabular component***- This patient's symptoms of progressive hip pain, **acetabular wear**, and **protrusio acetabuli** indicate a failure of the hemiarthroplasty due to erosion of the native acetabular cartilage and bone.- **Conversion to total hip replacement (THR)**, which involves implanting an acetabular component, is the definitive treatment to provide a durable articulation, relieve pain, and restore function.*Conservative management with analgesia and walking aids*- This approach does not address the underlying **mechanical failure** and progressive bone loss from the worn acetabulum.- Given the **progressive nature** of the condition and severe weight-bearing pain, conservative measures are unlikely to provide adequate long-term relief or prevent further damage.*Excision arthroplasty (Girdlestone procedure)*- The **Girdlestone procedure** is a salvage operation involving removal of the femoral head/prosthesis without replacement, leading to a flail, shortened, and often painful limb.- It is typically reserved for severe complications like **recurrent infection** or when other reconstruction options are not feasible, not for primary acetabular wear in an otherwise healthy elderly patient.*Revision to uncemented hemiarthroplasty*- A revision hemiarthroplasty would only replace the femoral component, leaving the **damaged and worn native acetabulum** to articulate with the new prosthetic head.- This would inevitably lead to continued **acetabular erosion** and recurrence of the patient's symptoms, as the core problem is not resolved.*Hip arthrodesis*- **Hip arthrodesis**, or surgical fusion of the hip, eliminates pain but results in the **complete loss of hip joint motion**, severely impacting daily activities.- While it can provide pain relief, it offers a significantly poorer functional outcome compared to **total hip replacement**, especially for an active elderly individual.

Question 72: A 44-year-old man presents to the Emergency Department with a 6-hour history of severe lower back pain that started suddenly while coughing. He describes severe pain radiating down the posterior aspect of his right leg to the heel. He is unable to stand on his tiptoes on the right foot. Examination reveals reduced right ankle jerk and numbness over the lateral border of the foot. Straight leg raise is positive at 30° on the right. Which nerve root is most likely compressed?

A. S1 (Correct Answer)
B. L4
C. L3
D. L5
E. S2

Explanation: ***S1*** - Compression of the **S1 nerve root** is characterized by weakness in **plantarflexion**, making it difficult to **stand on tiptoes**. - Key clinical markers include a **diminished ankle jerk reflex** (Achilles reflex) and sensory loss or numbness localized to the **lateral border of the foot** and heel. *L4* - An **L4 nerve root** injury specifically affects the **quadriceps**, leading to weakness in **knee extension** and difficulty climbing stairs. - Clinical examination would typically reveal a **reduced knee jerk reflex** (patellar reflex) and numbness along the **medial malleolus** and medial aspect of the leg. *L3* - **L3 radiculopathy** presents with sensory changes over the **anterior thigh** and the medial aspect of the knee. - It is associated with **hip flexion** weakness (iliopsoas) and may also contribute to a **diminished patellar reflex** alongside the L4 root. *L5* - **L5 nerve root** compression characteristically involves weakness in **great toe extension** (extensor hallucis longus) and difficulty **walking on heels** (dorsiflexion). - Sensory deficits are found on the **dorsum of the foot** and the first web space, but the **ankle reflex remains intact**. *S2* - Compression of the **S2 nerve root** is relatively rare and typically presents with sensory loss along the **posterior aspect of the thigh**. - Motor deficits are less distinct than higher levels but may involve some weakness in **knee flexion** or minor intrinsic foot muscle dysfunction.

Question 73: A 68-year-old man undergoes cannulated screw fixation for an undisplaced Garden II intracapsular neck of femur fracture. Post-operative radiographs show three parallel screws in inverted triangle configuration with good position. At 6 weeks post-operatively, he reports increasing hip pain and inability to weight bear. Radiographs show screw cut-out with varus collapse of the femoral head. Which biomechanical principle was most likely violated during the initial fixation?

A. Inadequate reduction with posterior tilt of the femoral head fragment (Correct Answer)
B. Use of cortical screws instead of cancellous screws
C. Insufficient screw purchase in the femoral head with threads not crossing the fracture
D. Screws positioned too anteriorly missing the posterosuperior quadrant
E. Excessive screw length causing penetration through the articular surface

Explanation: ***Inadequate reduction with posterior tilt of the femoral head fragment***- Successful internal fixation of femoral neck fractures is highly dependent on **anatomical reduction**; a **posterior tilt** greater than 20 degrees is associated with a high rate of fixation failure and **varus collapse**.- Even if screw placement appears ideal, a **malreduced fracture** creates unstable biomechanical forces and eccentric loading that the implants cannot withstand during weight-bearing.*Use of cortical screws instead of cancellous screws*- Standard practice for neck of femur fractures involves **cannulated cancellous screws** because they are designed to provide compression and better purchase in the metaphyseal bone.- While using the wrong screw type would be a technical error, it would not specifically lead to **varus collapse** if the initial positioning and reduction were perfect.*Insufficient screw purchase in the femoral head with threads not crossing the fracture*- To provide compression, the **screw threads** must completely cross the fracture line and reside within the **femoral head**.- If threads were across the fracture line (staying in the distal fragment), the screw would act as a **peg**, but this error would be visible on immediate post-operative films, unlike the gradual collapse described.*Screws positioned too anteriorly missing the posterosuperior quadrant*- Screws should ideally be placed in the **posterosuperior** and **inferior** regions to engage the dense bone and resist mechanical loads.- However, the prompt states the screws were in a **good position** and an **inverted triangle configuration**, suggesting this technical placement was initially documented as correct.*Excessive screw length causing penetration through the articular surface*- **Intra-articular penetration** causes immediate joint damage and pain rather than a delayed **varus collapse** at 6 weeks.- While serious, this is a complication of **over-drilling** or improper measurement, not a biomechanical violation leading to the gradual displacement of the fracture fragment.

Question 74: A 52-year-old woman with metastatic breast cancer presents with a 3-week history of progressive thoracic back pain. She now reports difficulty walking, with weakness in both legs. Neurological examination reveals grade 4/5 power in hip flexion bilaterally, brisk knee reflexes, upgoing plantars, and a sensory level at T8. Anal tone and perianal sensation are normal. What is the most likely anatomical site of pathology?

A. Thoracic spinal cord compression above the conus medullaris (Correct Answer)
B. Cauda equina compression below L2
C. Bilateral lumbar nerve root compression at L2-L4
D. Central disc prolapse at thoracolumbar junction
E. Multiple peripheral nerve lesions

Explanation: ***Thoracic spinal cord compression above the conus medullaris***- The presence of **upper motor neuron (UMN)** signs, such as **brisk knee reflexes** and **upgoing plantars (Babinski sign)**, indicates pathology involving the spinal cord itself rather than nerve roots.- A **sensory level at T8** and progressive thoracic back pain strongly localize the compression to the **thoracic spine**, which is the most common site for **metastatic spinal cord compression**.*Cauda equina compression below L2*- This condition involves **lower motor neuron (LMN)** signs, such as diminished or absent reflexes and flaccid paralysis, which contradicts this patient's presentation.- Key features typically include **saddle anesthesia** and loss of **anal tone**, neither of which are present in this case.*Bilateral lumbar nerve root compression at L2-L4*- Compression of lumbar nerve roots would present with **LMN signs** specifically in the distribution of those roots, such as a **reduced knee-jerk reflex**.- It would not explain the **sensory level at T8** or the presence of **upgoing plantars**, which require a lesion above the lumbar spine.*Central disc prolapse at thoracolumbar junction*- A prolapse at this junction typically affects the **conus medullaris**, which usually presents with a mix of UMN and LMN signs and early **autonomic dysfunction** (bowel/bladder).- The high **sensory level at T8** suggests a more superior lesion than the thoracolumbar transition area (L1-L2).*Multiple peripheral nerve lesions*- Peripheral nerve pathology presents with **weakness and sensory loss** in specific nerve distributions without a clear **truncal sensory level**.- This would result in **absent or diminished reflexes** rather than the **hyperreflexia** and extensor plantar responses seen here.

Question 75: A 75-year-old man sustains an undisplaced Garden I intracapsular neck of femur fracture. He has a history of previous hip surgery on the same side for developmental dysplasia treated with multiple osteotomies 40 years ago, resulting in distorted anatomy. Pre-injury he was independently mobile. What is the most appropriate surgical management considering the anatomical distortion?

A. Cemented total hip replacement (Correct Answer)
B. Cannulated screw fixation
C. Uncemented total hip replacement
D. Dynamic hip screw fixation
E. Cemented hemiarthroplasty

Explanation: ***Cemented total hip replacement***- In a patient with **distorted anatomy** from previous osteotomies for **developmental dysplasia**, primary arthroplasty provides a more predictable outcome than internal fixation despite it being a Garden I fracture.- **Cementing** the components is preferred over uncemented options to ensure immediate stability and better long-term fixation in an elderly patient with potentially compromised bone quality.*Cannulated screw fixation*- While normally used for **Garden I fractures**, the **distorted anatomy** and likely poor bone stock from multiple previous surgeries make screw trajectory and stability technically difficult.- There is a high risk of **non-union** or failure of fixation in a hip with a history of significant structural alteration.*Uncemented total hip replacement*- The **distorted femoral canal** and previous bone scarring from osteotomies make achieving a stable "press-fit" with an **uncemented prosthesis** technically challenging.- Uncemented stems in patients over 75 are associated with a higher risk of **periprosthetic fractures** compared to cemented stems.*Dynamic hip screw fixation*- A **Dynamic Hip Screw (DHS)** is typically the management of choice for **extracapsular (intertrochanteric)** fractures, not intracapsular ones.- It provides suboptimal rotational stability for **femoral neck fractures** and would be particularly difficult to place correctly in this distorted femur.*Cemented hemiarthroplasty*- **Hemiarthroplasty** is less ideal for a patient who was **independently mobile** and active pre-injury, as a Total Hip Replacement (THR) offers better functional outcomes.- Given the existing **hip dysplasia** and previous surgeries, there is a high likelihood of pre-existing **acetabular wear**, making a THR the more appropriate reconstructive choice.

Question 76: A 58-year-old man presents with a 12-week history of lower back pain and morning stiffness lasting over 2 hours. He reports the pain improves with exercise but worsens with rest. Examination shows reduced lumbar spine flexion (Schober's test <15cm expansion). Plain radiographs of the lumbar spine and pelvis are normal. ESR is 45 mm/hr, CRP 28 mg/L, and HLA-B27 is positive. What is the most appropriate next investigation to establish the diagnosis?

A. MRI of sacroiliac joints and spine (Correct Answer)
B. Bone scintigraphy (technetium-99m)
C. CT scan of pelvis and lumbar spine
D. Repeat plain radiographs in 6 months
E. Rheumatoid factor and anti-CCP antibodies

Explanation: ***MRI of sacroiliac joints and spine*** - In patients with strong clinical features of **inflammatory back pain** and a **positive HLA-B27** but normal plain radiographs, **MRI** is the gold standard for detecting **early sacroiliitis** (bone marrow edema) and active inflammation in the spine. - This investigation is crucial for diagnosing **non-radiographic axial spondyloarthritis**, which allows for early intervention and management, preventing disease progression as per **ASAS criteria**. *Bone scintigraphy (technetium-99m)* - Bone scintigraphy has **low specificity** for diagnosing axial spondyloarthritis and may show false positives from various inflammatory or degenerative conditions. - It cannot accurately visualize early **bone marrow edema** in the sacroiliac joints, which is the hallmark of active inflammation in early disease. *CT scan of pelvis and lumbar spine* - While CT is sensitive for detecting established **bony erosions** and structural changes in advanced disease, it is **inferior to MRI** for identifying early **active inflammation** (bone marrow edema). - Furthermore, it exposes the patient to **ionizing radiation**, making MRI a preferred initial imaging modality for suspected early inflammatory spondyloarthritis. *Repeat plain radiographs in 6 months* - Plain radiographs often remain normal in the early stages of axial spondyloarthritis, and waiting 6 months would lead to a significant **diagnostic delay**. - Early diagnosis and treatment are critical to prevent **irreversible structural damage** and preserve function, which would be missed by delaying further imaging. *Rheumatoid factor and anti-CCP antibodies* - These serological markers are specific for **Rheumatoid Arthritis**, which presents differently, typically affecting peripheral joints in a symmetrical pattern, and is not indicated by the patient's axial symptoms. - Axial spondyloarthropathies, including the suspected condition in this patient, are generally **seronegative**, meaning these markers are not expected to be positive.

Question 77: A 66-year-old woman undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cement insertion, she suddenly becomes hypotensive (BP 75/40 mmHg), hypoxic (SpO2 85%), loses consciousness, and develops cardiac arrest. CPR is commenced immediately. What is the most likely underlying pathophysiological mechanism?

A. Embolisation of fat, bone marrow, cement, and air causing right heart strain and pulmonary hypertension (Correct Answer)
B. Anaphylactic reaction to methylmethacrylate monomer causing systemic vasodilation
C. Acute myocardial infarction triggered by surgical stress and blood loss
D. Massive pulmonary thromboembolism from dislodged deep vein thrombus
E. Exothermic reaction of cement causing thermal injury to surrounding tissues

Explanation: ***Embolisation of fat, bone marrow, cement, and air causing right heart strain and pulmonary hypertension*** - This clinical presentation, characterized by sudden **hypotension**, **hypoxia**, loss of consciousness, and cardiac arrest during cemented arthroplasty, is highly consistent with **Bone Cement Implantation Syndrome (BCIS)**. - The high intramedullary pressure created during cement insertion forces **fat**, **bone marrow**, **cement**, and **air** into the venous circulation, leading to a sudden increase in **pulmonary vascular resistance**, acute **right ventricular failure**, and subsequent cardiovascular collapse. *Anaphylactic reaction to methylmethacrylate monomer causing systemic vasodilation* - While **methylmethacrylate monomer** can cause cardiovascular effects, a true **anaphylactic reaction** is extremely rare and typically presents with cutaneous manifestations, bronchospasm, and profound **systemic vasodilation**, which would not primarily cause **pulmonary hypertension** and **right heart strain** as seen in BCIS. - The immediate, severe cardiopulmonary collapse during cementation points more specifically to a mechanical embolic event rather than a widespread allergic response. *Acute myocardial infarction triggered by surgical stress and blood loss* - Although surgical stress and blood loss can precipitate an **acute myocardial infarction (AMI)**, the abrupt onset of symptoms precisely at the moment of **cement insertion** is a hallmark of BCIS. - An AMI would typically involve **coronary artery occlusion** and manifest with specific **ECG changes** and cardiac enzyme elevation, which are less likely to present with such an immediate, dramatic cardiopulmonary collapse without prior signs directly at the moment of cementation. *Massive pulmonary thromboembolism from dislodged deep vein thrombus* - Patients undergoing hip surgery are at risk for **venous thromboembolism (VTE)**, but a massive **pulmonary thromboembolism (PTE)** from a dislodged **deep vein thrombus** would be less directly tied to the precise moment of **cement pressurization**. - BCIS involves a distinct type of emboli (fat, marrow, cement, air) and its acute onset is directly related to the mechanical process of cementation, distinguishing it from a typical PTE. *Exothermic reaction of cement causing thermal injury to surrounding tissues* - The polymerization of polymethylmethacrylate cement is an **exothermic reaction**, generating heat that can cause localized **thermal injury** and **bone necrosis**. - However, this is a local tissue complication and does not explain the acute systemic cardiopulmonary collapse, including severe **hypotension**, **hypoxia**, and **cardiac arrest**, which are characteristic of BCIS.

Question 78: A 71-year-old man with multiple myeloma presents with a 4-week history of progressive lower back pain, now with new onset bilateral leg weakness making walking impossible. He has urinary frequency but denies retention. Examination reveals grade 3/5 power in hip flexion bilaterally, grade 4/5 in knee extension, intact perianal sensation, and normal anal tone. Plain radiographs show lytic lesions in L2 and L3 vertebrae with >50% loss of vertebral body height at L2. What is the most appropriate next step in management?

A. Arrange urgent whole spine MRI and refer to spinal surgery within 24 hours (Correct Answer)
B. Start high-dose oral dexamethasone 16mg daily and arrange MRI within 1 week
C. Refer to oncology for chemotherapy and radiotherapy planning
D. Arrange urgent CT spine and interventional radiology for vertebroplasty
E. Prescribe analgesia, bed rest, and arrange urgent DEXA scan

Explanation: ***Arrange urgent whole spine MRI and refer to spinal surgery within 24 hours*** - This patient presents with signs of **Metastatic Spinal Cord Compression (MSCC)**, characterized by progressive neurological deficits (bilateral leg weakness) and vertebral collapse, requiring **urgent imaging and referral** within 24 hours. - A **whole spine MRI** is the gold standard to identify all potential compression sites and assess the degree of cord involvement; early surgical intervention is crucial to preserve ambulatory function and neurological status.*Start high-dose oral dexamethasone 16mg daily and arrange MRI within 1 week* - While **high-dose dexamethasone** is indicated to reduce peritumoral edema and swelling, delaying the MRI for one week is inappropriate for a suspected **oncological emergency** like MSCC. - NICE guidelines emphasize that imaging and definitive management decisions must be made within **24 hours** for patients with new or rapidly progressing neurological signs.*Refer to oncology for chemotherapy and radiotherapy planning* - **Chemotherapy and radiotherapy** are important long-term treatments for multiple myeloma and can be used for spinal metastases without cord compression, but they do not address the acute mechanical compression causing **rapidly progressing lower limb weakness**. - Immediate **surgical decompression or stabilization** is the priority when mechanical instability or rapid neurological decline is present, as their effects are not immediate enough for acute cord compression.*Arrange urgent CT spine and interventional radiology for vertebroplasty* - **Vertebroplasty** may help with pain from osteoporotic or malignant vertebral fractures and improve stability but does not relieve **neural element compression** (spinal cord or nerve roots) caused by tumor invasion. - **MRI** is superior to CT for visualizing the spinal cord and soft tissue involvement in MSCC, making it the preferred initial imaging modality in this scenario.*Prescribe analgesia, bed rest, and arrange urgent DEXA scan* - A **DEXA scan** is used for osteoporosis screening and is irrelevant in the acute management of a **malignancy-related spinal emergency** with neurological deficits. - **Bed rest** alone does not address the underlying cord compression and may exacerbate neurological deficits or lead to complications like venous thromboembolism without definitive treatment.

Question 79: What is the primary mechanism by which bisphosphonates reduce the risk of fragility fractures in patients with osteoporosis?

A. Inhibition of osteoclast-mediated bone resorption (Correct Answer)
B. Stimulation of osteoblast proliferation and bone formation
C. Increase intestinal calcium absorption
D. Enhancement of vitamin D synthesis
E. Promotion of parathyroid hormone secretion

Explanation: ***Inhibition of osteoclast-mediated bone resorption***- **Bisphosphonates** bind to **hydroxyapatite** crystals in the bone and are internalized by **osteoclasts**, where they inhibit the enzyme **farnesyl pyrophosphate synthase**.- This action disrupts the **mevalonate pathway**, leading to **osteoclast apoptosis** and reduced bone turnover, which preserves bone mineral density.*Stimulation of osteoblast proliferation and bone formation*- This describes the **anabolic** mechanism of action characteristic of **teriparatide** (PTH analog) rather than bisphosphonates.- **Bisphosphonates** are primarily **anti-resorptive** agents and do not directly stimulate new bone matrix production.*Increase intestinal calcium absorption*- This is the primary function of **Vitamin D** (calcitriol), which enhances the expression of calcium transport proteins in the gut.- **Bisphosphonates** focus on bone mineral stabilization and do not have a direct effect on the **gastrointestinal absorption** of minerals.*Enhancement of vitamin D synthesis*- **Vitamin D synthesis** occurs in the skin via **UV-B radiation** and is further processed in the liver and kidneys; it is not influenced by bisphosphonate therapy.- While adequate vitamin D is necessary for bisphosphonates to be effective, the drugs themselves do not alter **endogenous synthesis**.*Promotion of parathyroid hormone secretion*- **Parathyroid hormone (PTH)** secretion is regulated by serum calcium levels; promoting its secretion would actually increase bone resorption via high levels of **RANKL**.- **Bisphosphonates** may actually cause a transient, secondary increase in PTH due to mild lowering of serum calcium, but this is not their therapeutic mechanism.

Question 80: A 79-year-old woman with osteoporosis sustains a displaced Garden IV intracapsular neck of femur fracture. She was previously independently mobile with a walking stick. Her past medical history includes atrial fibrillation (on warfarin), stage 3b chronic kidney disease (eGFR 38 ml/min), and a mechanical aortic valve replacement 10 years ago. What is the most appropriate surgical management?

A. Cemented total hip replacement (Correct Answer)
B. Cemented hemiarthroplasty
C. Uncemented total hip replacement
D. Cannulated screw fixation
E. Non-operative management with analgesia

Explanation: ***Cemented total hip replacement***- NICE guidelines recommend **total hip replacement (THR)** for patients with displaced intracapsular fractures who were **independently mobile** (with no more than a stick) and have no cognitive impairment.- **Cementing** is mandatory in elderly patients with **osteoporosis** to provide immediate primary stability and reduce the risk of **periprosthetic fractures**.*Cemented hemiarthroplasty*- This is reserved for patients with significant **cognitive impairment** or those who were not previously mobile enough to benefit from a THR.- While technically easier, it results in poorer functional outcomes and potential **acetabular wear** over time compared to THR.*Uncemented total hip replacement*- Uncemented components carry a higher risk of **intraoperative fracture** and late thigh pain in elderly patients with lower **bone mineral density**.- Current evidence favors **cemented fixation** in this age group as it ensures better long-term implant survival and fewer revisions.*Cannulated screw fixation*- This is inappropriate for a **displaced Garden IV fracture** in an elderly patient due to an extremely high risk of **avascular necrosis** and non-union.- Internal fixation is generally reserved for **undisplaced fractures** or very young patients who require femoral head preservation.*Non-operative management with analgesia*- Conservative management is associated with high rates of **pneumonia**, **pressure sores**, and mortality due to prolonged immobility.- It is only considered in **moribund patients** where the risk of any anesthesia outweigh the benefits of surgical stabilization.

Question 81: A 67-year-old man presents with a 5-week history of progressively worsening lower back pain. He describes difficulty passing urine for the past week and has noticed numbness in his perineal area. On examination, there is reduced anal tone and bilateral leg weakness with absent ankle reflexes. Bladder scan shows 800ml post-void residual volume. What is the most appropriate immediate management?

A. Urgent MRI spine and neurosurgical referral within 24 hours (Correct Answer)
B. Start oral dexamethasone and arrange routine MRI within 2 weeks
C. Prescribe analgesia and physiotherapy referral
D. Arrange urgent CT lumbar spine and urology review
E. Insert urinary catheter and discharge with GP follow-up

Explanation: ***Urgent MRI spine and neurosurgical referral within 24 hours*** - The patient exhibits classic signs of **Cauda Equina Syndrome (CES)**, including progressively worsening lower back pain, **saddle anesthesia** (perineal numbness), **urinary retention** (difficulty passing urine, 800ml PVR), **reduced anal tone**, and **bilateral leg weakness with absent ankle reflexes**. - **CES is a neurosurgical emergency** requiring **urgent MRI of the spine** for diagnosis and immediate surgical decompression, ideally within **24-48 hours**, to prevent permanent neurological, bowel, and bladder dysfunction. *Start oral dexamethasone and arrange routine MRI within 2 weeks* - **Dexamethasone** is primarily used for **metastatic spinal cord compression** to reduce peritumoral edema, not directly indicated for the mechanical compression seen in typical CES. - A **routine MRI within 2 weeks** is unacceptable for suspected CES, as delayed diagnosis and intervention lead to a high risk of irreversible **nerve root damage**. *Prescribe analgesia and physiotherapy referral* - While analgesia may provide symptomatic relief, it does not address the critical underlying **spinal cord compression** that requires immediate surgical intervention. - **Physiotherapy** is contraindicated in the acute phase of CES, as mechanical manipulation can potentially worsen nerve damage or delay essential definitive treatment. *Arrange urgent CT lumbar spine and urology review* - **MRI** is the gold standard for diagnosing CES because it provides superior visualization of **soft tissues**, nerve roots, and the extent of compression in the spinal canal compared to **CT**. - While urinary symptoms are present, the primary pathology is neurological compression, making a **neurosurgical review** more appropriate and urgent than a urology review in the acute phase. *Insert urinary catheter and discharge with GP follow-up* - Inserting a **urinary catheter** is a supportive measure for managing urinary retention, but it does not treat the underlying cause of **CES**. - **Discharging the patient** with suspected CES and only GP follow-up is dangerous, as it would lead to a failure to address the surgical emergency and almost certainly result in permanent disability.

Question 82: A 73-year-old woman undergoes dynamic hip screw fixation for an intertrochanteric femur fracture. Post-operatively, she develops sudden onset dyspnoea, hypoxia (SpO2 88% on room air), confusion, and petechial rash over her chest. Her blood pressure is 95/60 mmHg and heart rate 115 bpm. Blood gas shows PaO2 7.8 kPa. What is the most likely diagnosis?

A. Pulmonary embolism
B. Fat embolism syndrome (Correct Answer)
C. Bone cement implantation syndrome
D. Myocardial infarction
E. Hospital-acquired pneumonia

Explanation: ***Fat embolism syndrome*** - The classic clinical triad of **respiratory distress** (dyspnoea, hypoxia), **neurological symptoms** (confusion), and a **petechial rash** (over the chest) is highly indicative of fat embolism syndrome. - This syndrome typically occurs **24 to 72 hours** after **long bone fractures** (e.g., intertrochanteric femur fracture) or orthopedic surgery, due to fat globules entering the systemic circulation. *Pulmonary embolism* - While presenting with sudden onset **dyspnoea and hypoxia**, a **petechial rash** and significant **confusion** are not typical features of pulmonary embolism. - It is a common postoperative complication, but the constellation of symptoms in this case points more specifically to FES. *Bone cement implantation syndrome* - This syndrome occurs **intra-operatively** during **cemented orthopedic procedures**, causing acute cardiovascular collapse. - Dynamic hip screw fixation is generally a **non-cemented** procedure, and the patient's symptoms developed **post-operatively**, not intra-operatively. *Myocardial infarction* - An MI typically presents with **ischemic chest pain**, characteristic **ECG changes**, and elevated **cardiac biomarkers** (e.g., troponins). - While it can cause hypotension and dyspnoea, it does not account for the **petechial rash** or the specific neurological presentation. *Hospital-acquired pneumonia* - This infection usually manifests more than **48 hours after hospital admission** with symptoms like fever, productive cough, and **pulmonary infiltrates** on imaging. - The sudden onset of confusion and the distinctive **petechial rash** are not characteristic features of hospital-acquired pneumonia.

Question 83: A 63-year-old woman presents with a 2-month history of severe lower back pain. She has lost 8 kg in weight and reports feeling generally unwell. She has a history of smoking 30 cigarettes per day for 40 years. Examination reveals tenderness over the L3 vertebra. What is the single most important investigation to arrange urgently?

A. Plain radiographs of lumbar spine
B. MRI lumbar spine (Correct Answer)
C. CT chest, abdomen, and pelvis
D. Bone scan
E. Serum prostate-specific antigen

Explanation: ***MRI lumbar spine*** - This patient presents with multiple **red flags** for **spinal malignancy**, including severe persistent back pain, unexplained weight loss, age over 50, and a significant smoking history, along with localized vertebral tenderness. - **Urgent MRI** is the most sensitive and specific investigation for suspected **spinal metastasis** or **spinal cord compression**, providing excellent visualization of the spinal cord, nerve roots, vertebral marrow, and surrounding soft tissues. *Plain radiographs of lumbar spine* - **Plain X-rays** are insensitive for detecting early **bone metastases**, as they require a significant amount of bone destruction (typically 30-50%) to be visible. - They do not adequately visualize the **spinal cord** or **soft tissues**, making them insufficient to assess for **spinal cord compression** which is a critical concern. *CT chest, abdomen, and pelvis* - While a **CT scan** of the chest, abdomen, and pelvis is essential for **staging** a potential **primary malignancy** (especially lung cancer in a heavy smoker), it is not the initial urgent investigation for assessing the **spine** itself. - It offers less detail than MRI for evaluating the **spinal cord** and marrow, and typically follows MRI if spinal pathology is confirmed and a primary source is sought. *Bone scan* - A **bone scan** is highly sensitive for detecting areas of increased **osteoblastic activity** (often seen in metastases) but lacks specificity and anatomical detail. - It cannot provide the necessary information about **spinal cord involvement** or the extent of **epidural compression**, which is crucial for immediate management decisions. *Serum prostate-specific antigen* - This investigation is completely **inappropriate** for this patient, as **prostate-specific antigen (PSA)** is a tumor marker exclusively used for screening and monitoring **prostate cancer**, a disease specific to males. - The clinical context points towards malignancies common in women and smokers, such as **lung** or **breast cancer**, not prostate cancer.

Question 84: A 50-year-old man presents with a 3-month history of lower back pain and morning stiffness lasting 2 hours that improves with exercise. He reports waking at night due to pain. Examination reveals reduced chest expansion (3 cm) and reduced cervical spine rotation. ESR is 40 mm/hr. What is the most appropriate initial pharmacological management?

A. Paracetamol and reassurance
B. Non-steroidal anti-inflammatory drug (NSAID) at full dose (Correct Answer)
C. Low-dose oral corticosteroid
D. Disease-modifying antirheumatic drug (methotrexate)
E. TNF-alpha inhibitor (adalimumab)

Explanation: ***Non-steroidal anti-inflammatory drug (NSAID) at full dose***- **NSAIDs** are the first-line pharmacological treatment for **ankylosing spondylitis** (AS), providing significant relief for inflammatory back pain and stiffness.- They should be used at the **maximum tolerated dose** for at least 2–4 weeks to evaluate effectiveness before considering alternative treatments.*Paracetamol and reassurance*- **Paracetamol** is generally inadequate as monotherapy for **inflammatory back pain** because it lacks the necessary anti-inflammatory properties found in NSAIDs.- Simply offering reassurance is inappropriate given the clinical evidence of **reduced chest expansion** and **spinal mobility**, which necessitate active management.*Low-dose oral corticosteroid*- **Oral corticosteroids** are not recommended for the routine management of **axial disease** in ankylosing spondylitis due to a lack of evidence for long-term efficacy.- While useful for acute flares of **peripheral arthritis**, they do not prevent the progression of spinal fusion or provide sustained relief in axial spondyloarthritis.*Disease-modifying antirheumatic drug (methotrexate)*- **Conventional synthetic DMARDs** like **methotrexate** or sulfasalazine have no proven benefit in treating the **axial (spinal) symptoms** of AS.- These agents are only considered if there is concurrent **peripheral joint involvement** (e.g., dactylitis or arthritis in the limbs).*TNF-alpha inhibitor (adalimumab)*- **TNF-alpha inhibitors** are highly effective but are reserved for patients who have failed to respond to at least two different **NSAIDs** over a period of 4 weeks.- They are **second-line** biological therapies and involve strict criteria regarding disease activity scores (e.g., BASDAI) before initiation.

Question 85: A 58-year-old woman with known osteoporosis (T-score -3.2) sustains an undisplaced Garden I intracapsular neck of femur fracture. She is independently mobile and has no significant comorbidities. Intraoperatively, during attempted cannulated screw fixation, the fracture displaces. What is the most appropriate management?

A. Continue with cannulated screw fixation as originally planned
B. Convert to dynamic hip screw fixation
C. Convert to cemented hemiarthroplasty (Correct Answer)
D. Abandon surgery and manage conservatively
E. Convert to uncemented total hip replacement

Explanation: ***Convert to cemented hemiarthroplasty*** - Once an intracapsular fracture **displaces intraoperatively**, the risk of **avascular necrosis (AVN)** and **non-union** increases significantly, making internal fixation unreliable. - **Cemented hemiarthroplasty** is the standard recommended treatment for displaced intracapsular fractures in elderly patients as it allows for **immediate weight-bearing** and avoids the complications of fixation failure. *Continue with cannulated screw fixation as originally planned* - Internal fixation is only indicated for **undisplaced (Garden I and II)** fractures; proceeding after displacement leads to high rates of **re-operation** and failure. - The **retinacular blood supply** to the femoral head is likely compromised by the displacement, making hardware failure or AVN highly probable. *Convert to dynamic hip screw fixation* - A **Dynamic Hip Screw (DHS)** is primarily indicated for **extracapsular (intertrochanteric)** hip fractures, not for intracapsular fractures. - It does not address the risk of **femoral head osteonecrosis** associated with displaced intracapsular fractures. *Abandon surgery and manage conservatively* - Conservative management is generally inappropriate for a displaced hip fracture as it leads to **prolonged immobility**, increasing the risk of **pneumonia**, **pressure sores**, and **VTE**. - Surgery is essential to restore **mobility** and provide effective **pain relief** in an independently mobile patient. *Convert to uncemented total hip replacement* - While **Total Hip Replacement (THR)** is considered for active patients, **cemented fixation** is usually preferred over uncemented in patients with a **T-score of -3.2** (severe osteoporosis) to prevent periprosthetic fractures. - THR is more commonly reserved for patients with **pre-existing osteoarthritis** or those who are extremely active, whereas hemiarthroplasty is a standard response to intraoperative displacement in this age group.

Question 86: A 66-year-old man undergoes hemiarthroplasty for a displaced intracapsular neck of femur fracture. On day 3 post-operatively, he develops acute shortness of breath, confusion, and a petechial rash over his chest and conjunctiva. His oxygen saturation is 88% on room air. Blood tests show: Hb 95 g/L (previously 115 g/L), platelets 85×10⁹/L (previously 250×10⁹/L). What is the most likely diagnosis?

A. Hospital-acquired pneumonia
B. Pulmonary embolism from deep vein thrombosis
C. Fat embolism syndrome (Correct Answer)
D. Bone cement implantation syndrome
E. Transfusion-related acute lung injury

Explanation: ***Fat embolism syndrome*** - The patient presents with the classic clinical triad of **respiratory distress** (acute shortness of breath, O2 sat 88%), **neurological dysfunction** (confusion), and a **petechial rash** (chest and conjunctiva) occurring 24–72 hours after orthopedic surgery (day 3 post-op). - This diagnosis is strongly supported by the associated lab findings of **thrombocytopenia** (platelets 85×10⁹/L) and a drop in **hemoglobin** (Hb 95 g/L), which are consistent with the systemic inflammatory response seen in FES. *Hospital-acquired pneumonia* - While pneumonia can cause shortness of breath and hypoxemia, it typically presents with **fever**, **cough** (often productive), and evidence of **pulmonary infiltrates** on imaging. - It does not explain the presence of a **petechial rash** or the acute drops in **hemoglobin** and **platelets** characteristic of FES. *Pulmonary embolism from deep vein thrombosis* - PE can cause acute shortness of breath and hypoxemia, but it typically presents without a **petechial rash** or the profound **neurological changes** (confusion) seen in this patient. - While PE can cause some hemodynamic instability, **thrombocytopenia** and a significant drop in **hemoglobin** are not direct features of acute pulmonary thromboembolism. *Bone cement implantation syndrome* - BCIS is an acute, often severe, physiological disturbance that occurs *intra-operatively* or immediately *post-operatively* (within minutes to hours) during or after the **cementing of prostheses**. - The patient's symptoms developing on **day 3 post-operatively** make BCIS an unlikely diagnosis, as its onset is much earlier. *Transfusion-related acute lung injury* - TRALI is an acute respiratory distress syndrome that develops within **6 hours** of receiving a **blood product transfusion**. - There is no mention of a recent blood transfusion in the patient's history, and the symptoms, particularly the **petechial rash** and the timing, are not consistent with TRALI.

Question 87: A 45-year-old woman with a 12-week history of inflammatory back pain has normal plain radiographs of her sacroiliac joints. Her HLA-B27 is positive and inflammatory markers are elevated (CRP 45 mg/L). What is the most appropriate next investigation to establish the diagnosis?

A. Repeat plain radiographs in 3 months
B. CT scan of sacroiliac joints
C. MRI of sacroiliac joints with STIR sequences (Correct Answer)
D. Bone scintigraphy
E. Dual-energy X-ray absorptiometry (DEXA) scan

Explanation: ***MRI of sacroiliac joints with STIR sequences***- **MRI** is the gold standard for diagnosing **non-radiographic axial spondyloarthritis** as it can detect **bone marrow edema** and active inflammation long before changes appear on X-ray.- **STIR (Short Tau Inversion Recovery)** sequences are specifically used to highlight **edema**, which is a hallmark of active sacroiliitis according to the **ASAS criteria**.*Repeat plain radiographs in 3 months*- **Structural changes** such as erosions, sclerosis, or ankylosis visible on plain films can take **years** to develop; a 3-month window is insufficient to detect progress.- Relying on radiographs alone delays diagnosis and initiation of treatment in patients with **early inflammatory disease**.*CT scan of sacroiliac joints*- While **CT** is superior to X-rays for viewing **bone erosions** and structural damage, it cannot detect **active inflammation** or bone marrow edema.- It involves a high dose of **ionizing radiation** to the pelvis, making it less favorable than MRI for initial diagnostic screening.*Bone scintigraphy*- **Bone scans** are highly sensitive for detecting increased bone turnover but are **non-specific**, as uptake can occur due to infection, trauma, or degenerative disease.- It lacks the anatomical resolution and specificity required to confirm a diagnosis of **sacroiliitis** in the context of spondyloarthropathy.*Dual-energy X-ray absorptiometry (DEXA) scan*- **DEXA scans** are utilized to measure **bone mineral density** and diagnose osteoporosis, not to identify inflammatory or structural joint disease.- Although patients with axial spondyloarthritis are at higher risk for **osteoporosis**, this scan does not establish the primary diagnosis of the inflammatory condition.

Question 88: A 77-year-old woman with a displaced intracapsular neck of femur fracture is being counselled for surgery. She is independently mobile with a stick and has mild osteoarthritis of the ipsilateral hip with occasional pain. She has no significant comorbidities. Which surgical option should be offered?

A. Cemented hemiarthroplasty
B. Uncemented hemiarthroplasty
C. Cemented total hip replacement (Correct Answer)
D. Uncemented total hip replacement
E. Cannulated screw fixation

Explanation: ***Cemented total hip replacement*** - According to **NICE guidelines**, patients with **displaced intracapsular fractures** who were previously mobile (at least outdoors with a stick) and have **symptomatic osteoarthritis** should receive a **total hip replacement (THR)**. - A **cemented** approach is preferred in older patients to provide immediate stability, facilitate early weight-bearing, and minimize the risk of periprosthetic fractures.*Cemented hemiarthroplasty* - This is generally indicated for patients who are less mobile or have significant cognitive impairment, rather than those with high functional status. - It is unsuitable here because the patient has **ipsilateral hip arthritis**, which would likely cause persistent post-operative pain if the acetabulum is not replaced.*Uncemented hemiarthroplasty* - **Uncemented** prostheses are associated with higher rates of intra-operative and post-operative **periprosthetic fractures** in elderly, osteoporotic bone. - Like cemented hemiarthroplasty, it fails to address the patient's existing **osteoarthritis**, leading to poorer long-term functional outcomes.*Uncemented total hip replacement* - While THR is the correct procedure, the **uncemented** technique is less favorable than cemented in this demographic due to inferior fixation in aged bone. - Evidence suggests that **cemented fixation** offers better long-term implant survival and lower rates of revision in patients over 65.*Cannulated screw fixation* - This internal fixation method is typically reserved for **undisplaced** intracapsular fractures or very young patients. - In an elderly patient with a **displaced fracture**, this option carries an unacceptable risk of **avascular necrosis** and non-union.

Question 89: A 54-year-old man presents with a 5-month history of lower back pain that radiates to both buttocks and posterior thighs. The pain is worse when walking and relieved by sitting or leaning forward. He can walk further when pushing a shopping trolley. Neurological examination of the lower limbs is normal when supine. Peripheral pulses are palpable and symmetrical. What is the most likely diagnosis?

A. Peripheral arterial disease with intermittent claudication
B. Lumbar spinal stenosis (Correct Answer)
C. Bilateral L5-S1 disc herniation
D. Abdominal aortic aneurysm
E. Degenerative spondylolisthesis

Explanation: ***Lumbar spinal stenosis*** - The patient exhibits classic **neurogenic claudication**, characterized by lower back pain radiating to the buttocks and thighs, worsened by walking and relieved by **spinal flexion** (sitting or leaning forward). - The **'shopping trolley sign'**, where leaning forward allows walking further, is a hallmark as it increases the cross-sectional area of the **lumbar spinal canal**, relieving pressure on neural elements. *Peripheral arterial disease with intermittent claudication* - **Vascular claudication** from PAD is typically relieved by simply standing still and is not influenced by spinal posture or leaning forward. - The presence of **palpable and symmetrical peripheral pulses** makes significant peripheral arterial disease highly unlikely as the cause of these symptoms. *Bilateral L5-S1 disc herniation* - Disc herniation usually presents with **acute radicular pain**, often exacerbated by sitting, coughing, or a **positive Straight Leg Raise test**, rather than the relief seen with leaning forward. - It rarely presents with the specific type of **postural neurogenic claudication** described, which is characteristic of spinal stenosis. *Abdominal aortic aneurysm* - While a large or leaking **AAA** can cause referred back pain, it does not typically present with the **postural-dependent claudication** symptoms triggered by walking and relieved by leaning. - A physical examination for AAA would likely reveal a **pulsatile abdominal mass**, which is not indicated, and the relief with spinal flexion is not a feature. *Degenerative spondylolisthesis* - Although it can contribute to **spinal stenosis**, isolated **spondylolisthesis** typically causes localized back pain that worsens with lumbar extension and improves with rest. - The specific clinical presentation of **neurogenic claudication** with the characteristic positional relief is best described as **lumbar spinal stenosis**, even if spondylolisthesis is an underlying anatomical cause.

Question 90: A 68-year-old woman undergoes dynamic hip screw fixation for a stable two-part intertrochanteric fracture. Post-operatively, the tip-apex distance (TAD) is measured on radiographs. What is the maximum acceptable tip-apex distance to minimise the risk of screw cut-out?

A. 15 mm
B. 20 mm
C. 25 mm (Correct Answer)
D. 30 mm
E. 35 mm

Explanation: ***25 mm***- The **tip-apex distance (TAD)** is calculated as the sum of the distance from the screw tip to the femoral head apex on both **anteroposterior (AP)** and **lateral** views.- A **TAD of <25 mm** is the clinically recognized threshold that significantly minimizes the risk of **lag screw cut-out** in intertrochanteric fractures.*15 mm*- While a value of 15 mm is well within the safe zone, it is not the **maximum acceptable threshold** established by the **Baumgaertner** criteria.- Aiming for a TAD as low as 15 mm may increase the risk of **joint penetration** if the screw is placed too deeply into the subchondral bone.*20 mm*- A TAD of 20 mm is considered an **excellent placement** and is safer than the 25 mm limit, but it is not the highest threshold used to define acceptable risk.- Clinical studies show that mechanical stability is generally maintained at this level, but the standard benchmark for failure risk remains **25 mm**.*30 mm*- A TAD exceeding **25 mm** is associated with a significantly higher incidence of **mechanical failure** and screw migration.- At 30 mm, the screw is likely too **superficial** or poorly centered, providing insufficient purchase within the dense cancellous bone of the femoral head.*35 mm*- This value represents a **high risk of cut-out**, as the distance from the apex indicates the screw is not adequately supporting the fracture load.- **Technique errors**, such as placing the screw in the superior-posterior quadrant, often result in a high TAD and subsequent surgical failure.

Question 91: A 60-year-old man with metastatic prostate cancer presents with a 3-week history of severe lower back pain that is constant and unrelieved by rest. He has developed urinary retention over the past 24 hours and examination reveals saddle anaesthesia and reduced anal tone. His lower limbs show normal power but reduced sensation in an L5-S2 distribution bilaterally. What is the most appropriate immediate management?

A. Urgent MRI whole spine within 24 hours
B. Immediate MRI whole spine and neurosurgical referral (Correct Answer)
C. Plain radiographs of lumbar spine and referral to oncology
D. CT lumbar spine and admission for pain management
E. Catheterisation and routine MRI within 1 week

Explanation: ***Immediate MRI whole spine and neurosurgical referral*** - The patient presents with classic features of **cauda equina syndrome (CES)** secondary to **metastatic spinal cord compression (MSCC)**, evidenced by **saddle anaesthesia**, **urinary retention**, and reduced anal tone. - This is a **neurosurgical emergency**; immediate whole-spine imaging and specialist referral are required to facilitate **surgical decompression** or radiotherapy and prevent permanent neurological loss. *Urgent MRI whole spine within 24 hours* - While NICE guidelines mention 24 hours for stable patients with MSCC, the presence of **acute neurological deficits** (CES) demands **immediate** action rather than a delay. - Waiting 24 hours in the setting of **urinary retention** significantly increases the risk of irreversible **bladder and bowel dysfunction**. *Plain radiographs of lumbar spine and referral to oncology* - **Plain radiographs** lack the sensitivity to detect soft tissue masses or early **thecal sac compression** and are not indicated for diagnosis. - Delayed referral to oncology alone is inappropriate as it bypasses the urgent need for **decompressive surgery** or stabilization by neurosurgery. *CT lumbar spine and admission for pain management* - **CT scans** are less sensitive than **MRI** for evaluating the spinal cord and nerve roots and may miss critical levels of compression. - **Pain management** is supportive, but focusing on it without definitive surgical intervention for **nerve root compression** results in poor long-term outcomes. *Catheterisation and routine MRI within 1 week* - Catheterization treats the symptom of **urinary retention** but does not address the underlying **spinal compression** causing it. - A **routine MRI** timeline (1 week) is dangerous and negligent in the presence of "red flag" neurological symptoms like **reduced anal tone** and **saddle anaesthesia**.

Question 92: What percentage of the blood supply to the femoral head is provided by the medial femoral circumflex artery in adults?

A. 20-30%
B. 40-50%
C. 60-70%
D. 80-90% (Correct Answer)
E. 95-100%

Explanation: ***80-90%*** - The **medial femoral circumflex artery (MFCA)** is the dominant blood supply to the adult femoral head, contributing approximately **80-90%** of its circulation. - It gives rise to the **superior and inferior retinacular arteries**, which are frequently disrupted in **intracapsular femoral neck fractures**, leading to **avascular necrosis**. *20-30%* - This range significantly underestimates the arterial dominance of the MFCA; a contribution this low would describe the **lateral femoral circumflex artery** or minor collateral flow. - Clinical risk of **osteonecrosis** after fracture is high precisely because the MFCA provides far more than 30% of the total supply. *40-50%* - While nearly half, this value does not reflect the **anatomical reality** where the MFCA serves as the primary and near-exclusive source for the femoral head epiphysis. - This percentage would suggest a more balanced supply with the **obturator artery**, which is not the case in the adult skeleton. *60-70%* - Although the MFCA is the main source, its actual contribution is more substantial than two-thirds, reaching the **80-90%** threshold in most individuals. - This value fails to highlight the extreme vulnerability of the femoral head to **ischemia** when the circumflex vessels are compromised. *95-100%* - While the MFCA is the primary vessel, this range excludes the consistent, albeit minor, contributions from the **artery of the ligamentum teres** (obturator artery) and the **lateral circumflex artery**. - The **artery of ligamentum teres** typically provides about **5-10%** of the supply in adults, preventing the MFCA from accounting for the entire 100%.

Question 93: A 73-year-old man undergoes a cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cement insertion, he suddenly becomes hypotensive (BP 75/40 mmHg) and desaturates (SpO2 82%). His heart rate increases to 120 bpm. What is the most likely diagnosis?

A. Pulmonary embolism from deep vein thrombosis
B. Anaphylactic reaction to antibiotic prophylaxis
C. Fat embolism syndrome
D. Bone cement implantation syndrome (Correct Answer)
E. Myocardial infarction

Explanation: ***Bone cement implantation syndrome*** - This clinical picture is pathognomonic due to the timing of **sudden hypotension** and **hypoxia** occurring specifically during the **cementation phase** of hip surgery. - It is caused by the embolization of **bone marrow**, fat, and air into the pulmonary circulation, leading to a sudden increase in **pulmonary vascular resistance**. *Pulmonary embolism from deep vein thrombosis* - While a major cause of post-operative distress, it typically presents later in the **recovery period** rather than intraoperatively at the moment of cementing. - The immediate temporal relationship with **cement insertion** makes a primary DVT-related embolus less likely than BCIS. *Anaphylactic reaction to antibiotic prophylaxis* - Anaphylaxis usually presents shortly after **drug administration** and is often accompanied by **bronchospasm**, wheezing, or cutaneous signs like **urticaria**. - In this case, the hemodynamic collapse is directly synchronized with the surgical step of **bone cement** application. *Fat embolism syndrome* - Characterized by a classic triad of **hypoxemia**, **neurological abnormalities**, and a **petechial rash**, which aren't fully described here. - It typically follows a **latent period** of 24–72 hours after the initial trauma or surgery, unlike the acute intraoperative presentation of BCIS. *Myocardial infarction* - While an intraoperative **MI** can cause sudden hypotension and tachycardia, it lacks the specific association with the **reaming or cementing** process. - BCIS is a more common cause of acute **right-sided heart strain** and collapse during this specific part of a hemiarthroplasty.

Question 94: A 56-year-old woman presents with a 4-month history of lower back pain radiating down the posterior aspect of her right leg to the lateral foot. She describes numbness over the lateral foot and difficulty standing on tiptoe on the right side. Straight leg raise is positive at 40 degrees on the right. Which nerve root is most likely affected?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - Pain radiating down the **posterior leg to the lateral foot** and **numbness over the lateral foot** are classic dermatomal findings for the **S1 nerve root**. - Difficulty standing on **tiptoe** reflects weakness of the gastrocnemius and soleus muscles, which are primarily innervated by **S1** (plantarflexion). *L3* - **L3 radiculopathy** typically presents with pain and sensory loss over the **anterior thigh** and the medial aspect of the knee. - Motor weakness would involve **knee extension** (quadriceps) and a potentially diminished **knee-jerk reflex**. *L4* - Compression of the **L4 nerve root** causes pain in the anterior thigh and medial lower leg, often weakening **ankle dorsiflexion**. - It is classically associated with a reduced or absent **patellar (knee-jerk) reflex**. *L5* - **L5 radiculopathy** involves pain radiating to the **dorsum of the foot** and the **first web space** between the big toe and second toe. - Clinical weakness is most evident in **big toe extension** (extensor hallucis longus) and ankle dorsiflexion (tibialis anterior). *S2* - An **S2 nerve root** lesion is rare in isolation and usually involves pain or sensory loss in the **posterior thigh** and **perianal region**. - It is more commonly associated with pelvic floor dysfunction or alterations in **anal sphincter tone** rather than foot motor deficits.

Question 95: An 86-year-old woman sustains a Garden II intracapsular neck of femur fracture following a fall. She has severe dementia (AMTS 2/10), is normally bed-bound, and lives in a nursing home with full care. She has multiple comorbidities including severe COPD and ischaemic heart disease. What is the most appropriate initial management?

A. Cannulated screw fixation
B. Cemented hemiarthroplasty
C. Total hip replacement
D. Conservative management with analgesia and early mobilisation (Correct Answer)
E. Uncemented hemiarthroplasty

Explanation: ***Conservative management with analgesia and early mobilisation*** - This patient is **86 years old**, **bed-bound** with **severe dementia (AMTS 2/10)**, and has significant **comorbidities** (severe COPD, ischaemic heart disease). - For such a frail patient with very limited pre-injury mobility and severe cognitive impairment, the risks of surgery often outweigh any potential functional benefit, making **palliation** and comfort care paramount. *Cannulated screw fixation* - **Cannulated screw fixation** is typically used for stable, **undisplaced or minimally displaced intracapsular fractures** in younger, more active patients to preserve the femoral head. - In an 86-year-old bed-bound patient with severe comorbidities, the risks of fixation failure, avascular necrosis, and the need for revision surgery are high, and it would not significantly improve her baseline functional status. *Cemented hemiarthroplasty* - **Cemented hemiarthroplasty** is the preferred surgical option for **displaced intracapsular neck of femur fractures** in **elderly, independently mobile** patients or those who ambulate with aids. - Given her **severe dementia** and **bed-bound status**, this procedure would not restore her mobility, and she would still be at significant risk of complications (e.g., **bone cement implantation syndrome**) from a major surgery. *Total hip replacement* - **Total hip replacement (THR)** is generally reserved for **fit, active, and cognitively intact** elderly patients with displaced intracapsular fractures, or those with pre-existing hip pathology like arthritis. - This patient's **severe dementia**, non-ambulatory status, and multiple comorbidities make her unsuitable for a complex and extensive procedure like THR, which requires significant postoperative rehabilitation. *Uncemented hemiarthroplasty* - **Uncemented hemiarthroplasty** is generally avoided in the elderly population due to higher rates of **periprosthetic fracture** and less reliable fixation in osteoporotic bone compared to cemented options. - It offers no functional advantage for a bed-bound patient with severe comorbidities and cognitive impairment while carrying significant surgical risks.

Question 96: A 42-year-old man presents to his GP with a 6-week history of lower back pain. The pain is worse in the morning and improves with exercise. He also reports bilateral heel pain. On examination, there is reduced lumbar spine flexion with a Schober test measurement of 3 cm. What is the most appropriate initial investigation?

A. MRI lumbar spine
B. HLA-B27 genetic testing
C. Plain radiographs of the sacroiliac joints
D. Inflammatory markers (ESR and CRP) (Correct Answer)
E. Bone scan

Explanation: ***Inflammatory markers (ESR and CRP)***- In a patient presenting with suspected **ankylosing spondylitis** (AS) due to inflammatory back pain and heel pain, the initial step in primary care is to measure **ESR and CRP** to confirm the presence of **systemic inflammation**.- Elevated **CRP/ESR** levels support the clinical diagnosis of **inflammatory back pain** and help differentiate it from mechanical causes before progressing to more advanced imaging. *MRI lumbar spine*- While **MRI** is the most sensitive imaging modality for detecting early **sacroiliitis** (bone marrow edema), it is typically a second-line investigation if initial clinical and biochemical tests are inconclusive.- It is not the most appropriate immediate first step in the GP setting when **inflammatory bloods** have not yet been performed to establish the inflammatory nature of the pain. *HLA-B27 genetic testing*- **HLA-B27** is present in about 90% of patients with AS, but it is also found in a significant proportion of the **general population** who do not have the disease.- It is not used as a primary screening tool or **initial investigation** because a positive result does not confirm the diagnosis in isolation, and a negative result does not rule out spondyloarthritis. *Plain radiographs of the sacroiliac joints*- **X-rays** of the sacroiliac joints can show chronic changes such as **erosions, sclerosis**, or **fusion**, but these changes often take years to develop and may be absent in early disease.- Therefore, plain radiographs have low sensitivity for **early diagnosis** and are less useful than inflammatory markers in the initial workup for suspected inflammatory back pain. *Bone scan*- A **bone scan** is not routinely used for the diagnosis of **ankylosing spondylitis** as it lacks the specificity required to distinguish AS from other inflammatory processes.- Its primary role is in looking for **metastatic disease**, occult fractures, or other focal bone lesions, not the primary evaluation of **axial spondyloarthritis**.

Question 97: A 70-year-old woman presents to the Emergency Department following a fall. She has a shortened and externally rotated left leg. Radiographs confirm a displaced subcapital neck of femur fracture. She has an eGFR of 35 mL/min/1.73m². What surgical intervention is most appropriate for this patient?

A. Uncemented hemiarthroplasty (Correct Answer)
B. Cemented hemiarthroplasty
C. Cemented total hip replacement
D. Cannulated screw fixation
E. Dynamic hip screw fixation

Explanation: ***Uncemented hemiarthroplasty*** - For a **displaced subcapital neck of femur fracture** in an elderly patient, **arthroplasty** is preferred due to the high risk of **avascular necrosis** and non-union with internal fixation. - An **uncemented** approach is indicated to avoid **Bone Cement Implantation Syndrome (BCIS)**, as patients with **renal impairment (eGFR 35)** are at increased risk of cardiovascular instability from cement exposure. *Cemented hemiarthroplasty* - While often a standard choice for elderly hip fractures, the use of cement poses a significant risk of **Bone Cement Implantation Syndrome (BCIS)**. - This risk is heightened in patients with significant comorbidities like **renal impairment**, which can lead to life-threatening cardiovascular compromise. *Cemented total hip replacement* - **Total hip replacement (THR)** is generally reserved for more active elderly patients or those with **pre-existing osteoarthritis** of the hip. - The use of cement in THR also carries the risk of **BCIS**, which is particularly concerning for this patient with **renal impairment**, making it a less safe option. *Cannulated screw fixation* - **Cannulated screws** are typically reserved for **undisplaced** or minimally displaced **intracapsular fractures** where the femoral head blood supply is likely preserved. - For a **displaced subcapital fracture** in an elderly patient, fixation has a high rate of **non-union** and subsequent **avascular necrosis**, leading to poor functional outcomes. *Dynamic hip screw fixation* - A **dynamic hip screw (DHS)** is the treatment of choice for **extracapsular (intertrochanteric)** fractures, not intracapsular neck of femur fractures. - It is mechanically unsuitable for a **subcapital fracture** and would not provide stable fixation, potentially leading to failure and further complications.

Question 98: A 47-year-old woman presents with a 4-month history of lower back pain and progressive bilateral leg weakness. She has a history of breast cancer treated 18 months ago with mastectomy and adjuvant chemotherapy. MRI demonstrates a soft tissue mass causing spinal canal compromise at T12. Neurological examination reveals grade 4/5 power in both legs, intact sensation, and preserved sphincter function. After commencing dexamethasone, a multidisciplinary team meeting discusses management options. Which factor would most strongly favour surgical decompression over radiotherapy alone as the initial definitive treatment?

A. Single level of spinal involvement
B. Mechanical spinal instability on MRI (Correct Answer)
C. Previous radiotherapy to the thoracic spine
D. Slowly progressive neurological deficit over months
E. Patient is ambulatory at presentation

Explanation: ***Mechanical spinal instability on MRI***- **Mechanical spinal instability** detected on MRI is a primary indication for surgical decompression and stabilization, as **radiotherapy** alone cannot restore structural integrity or prevent further collapse of a compromised vertebral column.- The presence of instability often necessitates surgery to prevent **catastrophic neurological deterioration** and to provide immediate spinal **stabilization**, thereby improving pain and functional outcomes. *Single level of spinal involvement*- While a **single-level lesion** simplifies surgical planning, it does not inherently prioritize surgery over **radiotherapy** if the spine is stable and the tumor is considered radiosensitive.- Many cases of single-level **Metastatic Spinal Cord Compression (MSCC)** can be effectively managed with **radiotherapy** alone, especially when the spinal integrity is preserved. *Previous radiotherapy to the thoracic spine*- Previous **radiotherapy** to the *same* segment (T12) would strongly favor surgery due to the limited **spinal cord tolerance** for re-irradiation, but the question does not specify the exact location of prior radiation.- If the previous radiation was to a *different* level, it would not necessarily preclude **radiotherapy** (e.g., conventional or stereotactic radiosurgery) to the T12 lesion as an initial treatment option. *Slowly progressive neurological deficit over months*- A **slowly progressive neurological deficit** often allows sufficient time for **radiotherapy** to take effect, especially for tumors (like breast cancer) that are typically radiosensitive.- **Acute or rapidly progressive neurological deficits** are stronger indicators for urgent surgical decompression to prevent irreversible neurological damage. *Patient is ambulatory at presentation*- Being **ambulatory** is a strong positive prognostic factor, associated with better functional outcomes regardless of whether surgery or radiotherapy is chosen.- While it signifies preserved neurological function, it is not a specific criterion that mandates surgery over radiotherapy unless accompanied by **spinal instability** or a highly radioresistant tumor.

Question 99: A 67-year-old man undergoes a dynamic hip screw fixation for a stable intertrochanteric femur fracture. The operation is technically successful with good reduction and appropriate implant positioning on intraoperative fluoroscopy. Six months later, he presents with increasing hip pain and difficulty walking. Radiographs show the lag screw has cut out superiorly through the femoral head. Which intraoperative measurement error most likely contributed to this complication?

A. Tip-apex distance greater than 25 mm (Correct Answer)
B. Lag screw positioned in the superior quadrant of the femoral head on AP view
C. Insufficient lag screw length with tip 5 mm from subchondral bone
D. Barrel plate angle of 135 degrees used instead of 150 degrees
E. Lag screw placed anterior to the central axis on lateral view

Explanation: ***Tip-apex distance greater than 25 mm***- The **tip-apex distance (TAD)** is the most critical intraoperative predictor of **lag screw cut-out**; it is the sum of the distances from the screw tip to the femoral head apex on both AP and lateral views.- A **TAD >25 mm** is strongly associated with mechanical failure and superior migration of the screw through the femoral head, as seen in this patient.*Lag screw positioned in the superior quadrant of the femoral head on AP view*- While **superior positioning** is generally avoided, the **TAD** is a more specific and statistically validated measurement for predicting fixation failure.- Correct surgical technique aims for a **center-center** or **inferior-center** position to maximize purchase in the dense trabecular bone.*Insufficient lag screw length with tip 5 mm from subchondral bone*- A tip distance of **5 mm from the subchondral bone** is actually considered an appropriate and safe position to ensure adequate purchase without joint penetration.- Insufficient length usually refers to a distance much greater than 10-15mm, which would limit the **stability** of the construct and increase TAD.*Barrel plate angle of 135 degrees used instead of 150 degrees*- The choice of **plate angle** (typically 135°) is based on the patient's native **neck-shaft angle** and does not directly cause screw cut-out.- A **135-degree plate** is standard for most stable intertrochanteric fractures and provides appropriate dynamic compression.*Lag screw placed anterior to the central axis on lateral view*- **Anterior placement** on the lateral view is suboptimal but is less significantly associated with late cut-out compared to an overall high **TAD**.- Central placement on the **lateral radiograph** is the goal to ensure the screw remains within the thickest part of the femoral neck.

Question 100: A 38-year-old woman presents with a 6-week history of lower back pain and stiffness. She also reports a 2-week history of painful red eyes and worsening vision. She has a past medical history of psoriasis. Blood tests show: CRP 54 mg/L, ESR 42 mm/hr. Which extra-articular manifestation is she currently experiencing?

A. Scleritis
B. Anterior uveitis (Correct Answer)
C. Keratitis
D. Episcleritis
E. Posterior uveitis

Explanation: ***Anterior uveitis***- This patient likely has **psoriatic arthritis** with axial involvement, a type of **spondyloarthropathy** commonly associated with inflammatory eye conditions given her history of psoriasis and inflammatory back pain.- **Anterior uveitis** presents with a **painful red eye**, photophobia, and blurred vision, making it the most frequent extra-articular manifestation in these patients. *Scleritis*- Characterized by severe, **boring pain** that often radiates to the forehead and is more commonly associated with **rheumatoid arthritis** or systemic vasculitis.- It involves deeper layers of the eye than uveitis and typically does not present as a primary feature of axial spondyloarthropathies. *Keratitis*- Refers to **corneal inflammation**, which usually presents with a **foreign body sensation** and discharge rather than primarily inflammatory back pain markers.- It is not typically classified as a systemic extra-articular manifestation of **seronegative spondyloarthropathies** and is often infectious or related to dry eye. *Episcleritis*- Presents as a localized or diffuse **painless red eye** and rarely causes significant changes in vision or high levels of pain.- While it can occur in autoimmune diseases, it is generally **self-limiting** and less severe than the uveitis seen in this clinical scenario. *Posterior uveitis*- Primarily involves the **choroid and retina**, presenting with floaters or vision loss but usually **without the acute pain** and redness seen in anterior involvement.- It is less common in the context of HLA-B27 associated conditions compared to **acute anterior uveitis** and would not typically cause a painful red eye.

Question 101: A 65-year-old man sustains a subcapital neck of femur fracture with posterior comminution after a fall. He is an active independent individual who plays golf twice weekly. He has well-controlled type 2 diabetes and hypertension. Preoperatively, his surgeon discusses the risk of avascular necrosis of the femoral head if internal fixation is performed. In the context of this specific fracture pattern, which feature contributes most significantly to the elevated risk of avascular necrosis?

A. Patient's age over 60 years
B. Presence of posterior comminution (Correct Answer)
C. Time delay between injury and surgery
D. Subcapital location of the fracture
E. Patient's diabetic status

Explanation: ***Presence of posterior comminution*** - **Posterior comminution** indicates a severe mechanical disruption of the **posterior cortex**, which is the primary site through which the **retinacular vessels** (from the **medial circumflex femoral artery**) reach the femoral head. - This specific fracture characteristic is associated with a significantly higher risk of **avascular necrosis (AVN)** because it suggests the majority of the **60-80% blood supply** to the femoral head has been destroyed. *Patient's age over 60 years* - While **age** influences the choice between fixation and arthroplasty, it is a demographic factor rather than a **fracture pattern** characteristic that determines vascular compromise. - Older age is associated with **osteopenia**, which may lead to fixation failure, but it does not inherently cause AVN. *Time delay between injury and surgery* - Although a longer **time to reduction** can exacerbate ischemic damage, it is a perioperative management factor, not a feature of the "**specific fracture pattern**." - Modern evidence suggests that while urgent reduction is preferred, the **initial displacement** and comminution are more predictive of AVN outcome than time. *Subcapital location of the fracture* - All **subcapital fractures** are **intracapsular** and carry a baseline risk of vascular injury because they occur proximal to the vessel insertion. - However, the subcapital location itself is less predictive of poor outcome than the presence of **displacement** or **comminution** within that location. *Patient's diabetic status* - **Diabetes mellitus** increases the risk of **surgical site infection** and poor bone healing (non-union), but it is not the primary mechanism for **post-traumatic AVN**. - It is an important **comorbidity** for overall surgical risk but does not define the mechanical or vascular severity of the femoral neck fracture.

Question 102: A 72-year-old man presents with a 3-month history of lower back pain that has recently started radiating down his right leg to his foot. He describes weakness when trying to push down on the accelerator while driving. On examination, he has weakness of right ankle plantarflexion (4/5 power), reduced sensation over the right lateral foot and sole, and an absent right ankle reflex. Straight leg raise is positive at 40 degrees on the right. Which nerve root is most likely compressed?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - Compression of the **S1 nerve root** is characterized by weakness in **ankle plantarflexion** (gastrocnemius and soleus muscles), which directly explains the difficulty with pushing an accelerator pedal. - Sensory loss for an **S1 lesion** is classically found over the **lateral foot and sole**, and it is associated with a diminished or absent **Achilles (ankle) reflex**. *L3* - **L3 nerve root** compression primarily affects **knee extension** via the quadriceps and causes sensory loss over the **anterior/medial thigh**. - It is associated with a diminished **patellar reflex** (L3-L4), not the absent ankle reflex seen in this patient. *L4* - An **L4 radiculopathy** typically leads to weakness in **ankle dorsiflexion** and **knee extension**, with sensory changes over the **medial calf** and ankle. - This level is also assessed via the **patellar reflex**, which is inconsistent with the absent Achilles reflex in this case. *L5* - **L5 nerve root** compression often results in weakness of **big toe extension** (extensor hallucis longus) and foot **eversion**, leading to a foot drop. - Sensory loss occurs over the **dorsum of the foot** and the **first web space**, and there is no distinct reflex commonly tested for L5 alone. *S2* - **S2 compression** is less common and primarily presents with sensory loss over the **posterior thigh** and popliteal fossa. - While it contributes to plantarflexion, isolated **S2 lesions** would not typically present with the specific lateral foot sensory loss and absent ankle reflex that are hallmark signs of S1 involvement.

Question 103: A 53-year-old woman with known metastatic breast cancer presents to the Emergency Department with a 4-week history of worsening lower back pain, bilateral leg weakness, and urinary hesitancy that has progressed to urinary retention over the past 24 hours. On examination, power is 2/5 in both legs, there is saddle anaesthesia, and reduced anal tone. An urgent MRI demonstrates cord compression at L1. After commencing high-dose dexamethasone, what is the timeframe within which definitive treatment should be administered to optimise neurological recovery?

A. Within 6 hours of symptom onset
B. Within 24 hours of diagnosis (Correct Answer)
C. Within 48 hours of symptom onset
D. Within 1 week of presentation
E. Within 2 weeks of diagnosis

Explanation: ***Within 24 hours of diagnosis*** - For **Malignant Spinal Cord Compression (MSCC)**, NICE guidelines specify that definitive treatment, such as **surgical decompression** or **radiotherapy**, must be initiated within **24 hours** of MRI confirmation. - This timeframe is critical for maximizing **neurological recovery**, particularly for regaining motor function and **sphincter control** in patients with acute deterioration. *Within 6 hours of symptom onset* - While rapid intervention is essential, the **6-hour window** is more commonly associated with acute **ischaemic stroke** (thrombolysis) or **compartment syndrome**, rather than the standard for MSCC. - The guidelines for MSCC specifically anchor the 24-hour target to the **time of diagnosis** rather than the initial onset of vague symptoms. *Within 48 hours of symptom onset* - Waiting for **48 hours** from symptom onset is inappropriate because symptoms in this patient began **4 weeks ago**, making this timeframe irrelevant to the current emergency. - Delaying treatment beyond 24 hours from diagnosis significantly increases the risk of **permanent paraplegia** and irreversible loss of bladder function. *Within 1 week of presentation* - A **one-week** delay is far too long for an **oncological emergency** and would likely lead to a complete lack of neurological recovery. - Such a timeframe may be applicable for elective spinal procedures but not for **acute paralysis** or **cauda equina-like symptoms**. *Within 2 weeks of diagnosis* - This duration is associated with poor outcomes, as the greatest chance of recovery occurs if the patient is treated while still **ambulatory**. - By two weeks, the spinal cord damage from **ischaemia** and mechanical compression is usually **permanent** and refractory to late decompression.

Question 104: Which anatomical structure forms the boundary between intracapsular and extracapsular neck of femur fractures?

A. Insertion of the iliofemoral ligament
B. Intertrochanteric line anteriorly and intertrochanteric crest posteriorly
C. Attachment of the hip joint capsule to the femoral neck (Correct Answer)
D. Level of the lesser trochanter
E. Proximal extent of the periosteal covering of the femur

Explanation: ***Attachment of the hip joint capsule to the femoral neck*** - This anatomical landmark serves as the definitive boundary, as any fracture within this **fibrous capsule** is termed intracapsular and carries a high risk of **avascular necrosis**. - The capsule attaches to the **intertrochanteric line** anteriorly but stays roughly 1 cm proximal to the **intertrochanteric crest** posteriorly, defining the intracapsular space. *Insertion of the iliofemoral ligament* - The **iliofemoral ligament** (Bigelow's ligament) is a component of the fibrous capsule and reinforces it anteriorly, but the ligament itself is not the boundary identifier. - While it attaches near the **intertrochanteric line**, the anatomical definition of the fracture type is based on the entire **capsular reflection**, not a single ligament. *Intertrochanteric line anteriorly and intertrochanteric crest posteriorly* - This describes the **anatomical neck-shaft** junction, but the posterior attachment of the capsule occurs **proximal** to the crest. - Relying solely on the crest as a landmark would incorrectly classify the most distal portion of the posterior neck as **intracapsular**, when it is actually extracapsular. *Level of the lesser trochanter* - The **lesser trochanter** is a landmark for **extracapsular fractures**, specifically serving as a reference point for intertrochanteric and subtrochanteric classifications. - Fractures at this level do not disrupt the **retinacular vessels** found within the joint capsule, thus they have better healing potential than neck fractures. *Proximal extent of the periosteal covering of the femur* - The intracapsular neck is notable for its lack of a thick **periosteal layer**, which limits its ability to form a **callus** during fracture healing. - While this histological feature explains why these fractures are prone to **non-union**, the primary surgical boundary is defined by the **capsular attachment** site.

Question 105: A 69-year-old woman with a displaced intracapsular neck of femur fracture undergoes a cemented hemiarthroplasty. During cement insertion, she suddenly becomes hypotensive (blood pressure 75/40 mmHg), bradycardic (heart rate 42 bpm), and her oxygen saturations drop to 82%. She rapidly loses consciousness. What is the underlying pathophysiological mechanism of this complication?

A. Anaphylactic reaction to methylmethacrylate monomer
B. Air embolism from pressurisation of the femoral canal
C. Fat and cement emboli causing pulmonary hypertension and right heart strain (Correct Answer)
D. Acute myocardial infarction due to hypotension and tachycardia
E. Cerebrovascular accident due to paradoxical embolism

Explanation: ***Fat and cement emboli causing pulmonary hypertension and right heart strain***- This patient is experiencing **Bone Cement Implantation Syndrome (BCIS)**, caused by high pressure in the femoral canal forcing **fat, marrow, and cement particles** into the venous system.- These emboli increase **pulmonary vascular resistance**, leading to acute **right heart failure**, which manifests as severe **hypotension, hypoxia, and bradycardia** shortly after cement insertion.*Anaphylactic reaction to methylmethacrylate monomer*- While the monomer can cause direct **vasodilation**, true IgE-mediated anaphylaxis is very rare in this context.- The timing and hemodynamic collapse are more characteristic of **mechanical embolic obstruction** than an allergic reaction.*Air embolism from pressurisation of the femoral canal*- Though **air** can contribute to the embolic load during femoral canal pressurization, it is rarely the sole cause of cardiovascular collapse.- The clinical syndrome of BCIS is primarily driven by a shower of **marrow contents** and fat rather than simple air bubbles.*Acute myocardial infarction due to hypotension and tachycardia*- While hypotension can trigger a **Type 2 MI**, the primary event here is pulmonary hypertension; the patient is also **bradycardic**, not tachycardic.- An MI is a secondary consequence of the **circulatory collapse** caused by the emboli, not the primary pathophysiology of the sudden decline during cementation.*Cerebrovascular accident due to paradoxical embolism*- A **paradoxical embolism** would require a right-to-left shunt (like a patent foramen ovale) and would typically cause **focal neurological deficits**.- The systemic presentation of **hypoxia and hypotension** points towards a catastrophic pulmonary/cardiac event rather than a primary stroke.

Question 106: A 44-year-old woman presents with a 5-month history of lower back pain radiating to both buttocks and posterior thighs. The pain is worse after walking 200 metres and is relieved by sitting or leaning forward. She describes having to stop and lean on a shopping trolley for relief. Neurological examination is normal when supine but after walking, she develops reduced sensation in L5 and S1 distributions bilaterally. What is the most likely diagnosis?

A. Cauda equina syndrome
B. Lumbar spinal stenosis (Correct Answer)
C. Ankylosing spondylitis
D. Bilateral lumbar disc herniation
E. Peripheral vascular disease

Explanation: ***Lumbar spinal stenosis***- Characterized by **neurogenic claudication**, where leg pain and numbness are triggered by walking and relieved by spine flexion (the **'shopping trolley sign'**).- It occurs due to the narrowing of the spinal canal; symptoms worsen with **extension** (standing/walking) and improve as **flexion** (leaning forward) increases canal diameter.*Cauda equina syndrome*- Typically presents acutely with **saddle anesthesia**, **urinary retention**, and loss of anal sphincter tone, which are absent here.- It is a **surgical emergency** characterized by compression of multiple nerve roots, usually not relieved simply by leaning forward.*Ankylosing spondylitis*- Presents as **inflammatory back pain** that is typically worse in the morning and **improves with exercise**, the opposite of this patient's presentation.- Usually affects younger patients and is associated with **spinal stiffness** and sacroiliitis rather than exercise-induced neurological deficits.*Bilateral lumbar disc herniation*- While it can cause bilateral symptoms, it typically presents with **radicular pain** that is often worsened by sitting or coughing rather than walking.- It usually involves a more **constant neuropathic pain** pattern and is less likely to show the classic postural relief seen in stenosis.*Peripheral vascular disease*- Causes **vascular claudication** where pain is relieved simply by **standing still**, whereas neurogenic claudication specifically requires sitting or spinal flexion.- Physical examination would likely show **diminished peripheral pulses** and skin changes (atrophy/coolness), and is not typically associated with postural sensory changes.

Question 107: A 76-year-old man undergoes internal fixation with three cannulated screws for an undisplaced Garden II intracapsular neck of femur fracture. On the second postoperative day, he develops sudden onset confusion, tachypnoea (respiratory rate 32/min), and oxygen saturations of 88% on room air. His heart rate is 115 bpm and blood pressure 95/60 mmHg. A petechial rash is noted on his chest. What is the most likely diagnosis?

A. Pulmonary embolism
B. Bone cement implantation syndrome
C. Acute myocardial infarction
D. Fat embolism syndrome (Correct Answer)
E. Hospital-acquired pneumonia

Explanation: ***Fat embolism syndrome***- This patient presents with the classic triad of **Fat Embolism Syndrome (FES)**: **respiratory distress** (hypoxia, tachypnoea), **neurological deficit** (confusion), and a **petechial rash** on the chest.- FES typically occurs **24-72 hours** after an orthopedic procedure or long bone fracture, like a neck of femur fracture, due to the release of fat globules into the systemic circulation.*Pulmonary embolism*- While PE causes sudden **hypoxia** and **tachypnoea**, it is not typically associated with a **petechial rash** or acute global neurological symptoms like confusion.- PE usually presents slightly later in the postoperative course unless a **deep vein thrombosis (DVT)** was already present, and the rash is a key differentiating feature.*Bone cement implantation syndrome*- This involves hypoxia and hypotension occurring specifically during the **intraoperative period** at the time of cementation for arthroplasty.- This patient underwent **internal fixation with screws** without the use of bone cement, making this diagnosis impossible.*Acute myocardial infarction*- MI would typically present with **chest pain**, ECG changes, and elevated cardiac biomarkers like **troponins**.- While surgery can trigger a cardiac event, the specific triad of **hypoxia, confusion, and petechiae** is not characteristic of an acute myocardial infarction.*Hospital-acquired pneumonia*- HAP usually presents after **48 hours** with productive cough, fever, and focal consolidation on a chest X-ray.- It does not explain the **petechial rash** or the acute sudden onset of global neurological confusion seen here.

Question 108: What is the blood supply to the femoral head that is derived from the obturator artery and travels through the ligamentum teres?

A. Superior gluteal artery
B. Medial circumflex femoral artery
C. Lateral circumflex femoral artery
D. Artery of ligamentum teres (Correct Answer)
E. Inferior gluteal artery

Explanation: ***Artery of ligamentum teres*** - This vessel, also known as the **foveal artery**, is a branch of the **obturator artery** that travels within the **ligamentum teres** to supply the femoral head. - While it provides a significant portion of blood supply in **children**, its contribution in adults is minimal, typically accounting for only **10-15%** of femoral head vascularity. *Superior gluteal artery* - This artery exits the pelvis through the **greater sciatic foramen** and primarily supplies the **gluteus medius** and **gluteus minimus** muscles. - It does not travel through the ligamentum teres or provide direct blood supply to the **femoral head**. *Medial circumflex femoral artery* - This is the **dominant blood supply** to the adult femoral head, providing approximately **70%** of its vascularity via the **retinacular vessels**. - It originates from the **profunda femoris** and is frequently damaged in **intracapsular hip fractures**, leading to **avascular necrosis**. *Lateral circumflex femoral artery* - This artery primarily supplies the **femoral neck**, greater trochanter, and the **vastus lateralis** muscle. - It contributes to the extracapsular **arterial ring** at the base of the femoral neck but does not supply the head via the ligamentum teres. *Inferior gluteal artery* - This vessel supplies the **gluteus maximus** muscle and contributes to the **cruciate anastomosis** of the thigh. - It does not enter the hip joint capsule to provide nutrients to the **articular surface** of the femoral head.

Question 109: A 59-year-old man presents with a 2-week history of progressive lower back pain and new onset urinary retention requiring catheterisation. He has a past medical history of prostate cancer treated with radiotherapy 3 years ago. On examination, he has reduced power (3/5) in both legs, absent ankle reflexes bilaterally, and a palpable bladder. What is the most appropriate immediate management?

A. Urgent MRI whole spine within 24 hours
B. Prostate-specific antigen testing and urology referral
C. CT lumbar spine and referral to spinal surgery within 1 week
D. Lumbar spine radiographs and routine orthopaedic referral
E. Commence high-dose oral dexamethasone and arrange urgent MRI (Correct Answer)

Explanation: ***Commence high-dose oral dexamethasone and arrange urgent MRI*** - The patient's presentation with progressive back pain, new urinary retention, bilateral leg weakness, absent ankle reflexes, and a history of prostate cancer strongly indicates **metastatic spinal cord compression (MSCC)** or severe **cauda equina syndrome**. - Immediate administration of **high-dose dexamethasone** is crucial to reduce peritumoural oedema, followed by an **urgent MRI of the whole spine** to localize the compression and guide definitive treatment. *Urgent MRI whole spine within 24 hours* - While an **urgent MRI** is indispensable for diagnosis, it should not precede the immediate administration of **corticosteroids**. - Delaying steroid therapy can lead to irreversible **neurological damage** by allowing peritumoural oedema to worsen spinal cord compression. *Prostate-specific antigen testing and urology referral* - **PSA testing** and urology referral address the underlying cancer but do not provide immediate management for the acute neurological emergency. - This approach would result in a critical delay in treating **spinal cord compression**, risking permanent **paraplegia** and loss of bladder/bowel function. *CT lumbar spine and referral to spinal surgery within 1 week* - A **CT scan** is inferior to MRI for visualizing soft tissues like the spinal cord and nerve roots, making it less suitable for diagnosing compression. - A 1-week timeline for referral is unacceptable for such a severe neurological presentation, which requires **immediate intervention**. *Lumbar spine radiographs and routine orthopaedic referral* - **Plain radiographs** have poor sensitivity for detecting soft tissue compression of the spinal cord and cannot effectively rule out metastatic disease. - A **routine referral** is inappropriate for red-flag symptoms of **cauda equina syndrome** or MSCC, which necessitate emergency hospital admission and management.

Question 110: An 83-year-old woman sustains a Garden IV displaced intracapsular neck of femur fracture. She was fully mobile pre-injury using a walking stick outdoors. She has moderate dementia (Abbreviated Mental Test Score 6/10) but recognises family members and cooperates with care. Her comorbidities include hypertension and osteoarthritis of both knees. Which surgical procedure would provide the best functional outcome?

A. Cannulated screw fixation
B. Uncemented hemiarthroplasty
C. Cemented hemiarthroplasty
D. Uncemented total hip replacement
E. Cemented total hip replacement (Correct Answer)

Explanation: ***Cemented total hip replacement*** - According to **NICE guidelines**, patients who were able to **walk independently outdoors** (with no more than a stick) and are medically fit should be offered a total hip replacement (THR) over a hemiarthroplasty. - **Cemented fixation** is preferred in elderly patients to reduce the risk of **periprosthetic fractures**, minimize postoperative pain, and ensure better long-term implant stability. *Cannulated screw fixation* - This approach is generally reserved for **undisplaced (Garden I and II)** fractures; in a **Garden IV displaced** fracture, the risk of **non-union** and **avascular necrosis** is unacceptably high. - Displaced fractures in patients over 65 are routinely managed with **arthroplasty** rather than internal fixation to allow for immediate weight-bearing. *Uncemented hemiarthroplasty* - **Uncemented implants** in the elderly are associated with a higher risk of **intraoperative fractures** and increased mid-term postoperative thigh pain compared to cemented options. - Large randomized trials have demonstrated that **cemented arthroplasty** provides superior functional outcomes and lower mortality in this age group. *Cemented hemiarthroplasty* - While a reasonable alternative, this patient meets the criteria for THR because she was **independently mobile** outdoors and her **Abbreviated Mental Test Score (6/10)** does not represent severe cognitive impairment. - THR provides superior **long-term functional outcomes** and lower rates of reoperation due to **acetabular erosion** compared to hemiarthroplasty. *Uncemented total hip replacement* - Similar to hemiarthroplasty, **uncemented THR** carries a significantly higher risk of **periprosthetic femoral fracture** in osteoporotic elderly bone. - Standard evidence-based practice favors **cemented components** to ensure better initial stability and a more reliable bond between the bone and the prosthesis.

Question 111: A 26-year-old man presents to his GP with a 10-week history of lower back pain and stiffness that is worse in the morning and improves with exercise. He reports buttock pain that alternates sides. His father has a history of inflammatory bowel disease. On examination, there is reduced lumbar spine flexion with a Schober's test of 3 cm (normal >5 cm). Which initial investigation would be most appropriate to support the suspected diagnosis?

A. MRI lumbar spine (Correct Answer)
B. HLA-B27 testing
C. Plain radiograph of sacroiliac joints
D. Erythrocyte sedimentation rate and C-reactive protein
E. Rheumatoid factor and anti-CCP antibodies

Explanation: ***MRI lumbar spine*** - **MRI** is the gold standard for detecting **early inflammatory changes** like **bone marrow oedema** in axial spondyloarthritis (e.g., Ankylosing Spondylitis) before structural damage appears on X-rays. - Given the patient's strong clinical picture of inflammatory back pain, including reduced **lumbar spine flexion** (Schober's test 3 cm) and alternating buttock pain, MRI is the most sensitive investigation to confirm **active sacroiliitis** in early-stage disease. *HLA-B27 testing* - While **HLA-B27** is strongly associated with Ankylosing Spondylitis, it is present in 8% of the healthy population and is not diagnostic on its own. - It is useful for supporting a diagnosis in borderline cases or for risk stratification but does not provide direct visual evidence of **sacroiliitis** or spinal inflammation. *Plain radiograph of sacroiliac joints* - Radiographs only detect **chronic structural changes** such as erosions, sclerosis, or joint fusion, which may take years to develop. - It is often normal in the early phases of **axial spondyloarthritis** and lacks the sensitivity to detect acute inflammation compared to MRI. *Erythrocyte sedimentation rate and C-reactive protein* - **ESR and CRP** are non-specific markers of systemic inflammation that may be elevated in **spondyloarthropathies** but are not diagnostic. - A significant portion of patients with active **Ankylosing Spondylitis** may have normal inflammatory markers, reducing their utility as a primary diagnostic tool. *Rheumatoid factor and anti-CCP antibodies* - These tests are specific for **Rheumatoid Arthritis**, a different condition typically involving small peripheral joints, and worsening with rest rather than improving with exercise. - These markers are typically negative in **seronegative spondyloarthropathies** like Ankylosing Spondylitis, making them unhelpful for this suspected diagnosis.

Question 112: A 71-year-old woman presents to the Emergency Department following a fall from standing height. She has severe pain in her right hip and is unable to weight-bear. Examination reveals a shortened and externally rotated right leg. Plain radiograph confirms an intertrochanteric femur fracture with loss of the posteromedial cortical buttress. What is the most appropriate surgical management?

A. Dynamic hip screw fixation
B. Cannulated screw fixation
C. Cemented hemiarthroplasty
D. Intramedullary femoral nail (Correct Answer)
E. Total hip replacement

Explanation: ***Intramedullary femoral nail*** - Loss of the **posteromedial cortical buttress** indicates an **unstable** intertrochanteric fracture pattern, which requires more robust biomechanical support. - An **intramedullary device** (cephalomedullary nail) provides a shorter lever arm and better **load-sharing** capabilities than extramedullary devices in unstable fractures.*Dynamic hip screw fixation* - This is the treatment of choice for **stable** intertrochanteric fractures where the medial cortex remains intact. - In unstable patterns, such as this one, it is associated with a higher risk of **excessive collapse**, medialization of the shaft, and **implant failure**.*Cannulated screw fixation* - This technique is specifically used for **undisplaced or stable intracapsular** femoral neck fractures. - It does not provide sufficient stability or strength for **extracapsular** intertrochanteric injuries.*Cemented hemiarthroplasty* - While used frequently for **displaced intracapsular** fractures in the elderly, it is not standard primary management for intertrochanteric fractures. - Intertrochanteric bone is highly vascular with high **healing potential**, making internal fixation preferable over replacing the joint.*Total hip replacement* - Reserved for patients with pre-existing **hip osteoarthritis** or very specific complex intracapsular fractures in active older adults. - It is a more extensive procedure than necessary for an **intertrochanteric fracture**, which is better managed by preserving the native joint via nail fixation.

Question 113: A 49-year-old woman with a history of systemic lupus erythematosus treated with long-term prednisolone presents with insidious onset hip pain over 8 months. The pain is worse with weight-bearing and she has developed a limp. Plain radiographs show a crescent sign in the femoral head with some collapse of the articular surface. Blood tests show normal inflammatory markers. What is the underlying pathological process?

A. Septic arthritis of the hip joint
B. Inflammatory arthropathy secondary to lupus
C. Avascular necrosis of the femoral head (Correct Answer)
D. Osteoarthritis secondary to joint incongruity
E. Stress fracture of the femoral neck

Explanation: ***Avascular necrosis of the femoral head*** - The patient's history of **systemic lupus erythematosus (SLE)** and **long-term prednisolone** (corticosteroid use) are major risk factors for **avascular necrosis (AVN)**. - The **insidious onset hip pain** worse with weight-bearing, a limp, and the characteristic **crescent sign** on radiographs (indicating subchondral collapse) with subsequent articular surface collapse, are all highly indicative of AVN. *Septic arthritis of the hip joint* - Typically presents with **acute onset** severe pain, often accompanied by fever and significantly **elevated inflammatory markers**, which are absent in this case. - The chronic, insidious nature of the pain (8 months) and normal inflammatory markers make septic arthritis very unlikely. *Inflammatory arthropathy secondary to lupus* - While SLE can cause arthropathy, it usually presents as a **non-erosive polyarthritis** of smaller joints, not isolated hip pain with **femoral head collapse** and a **crescent sign**. - Lupus-related joint inflammation does not typically cause the specific radiographic features of bone necrosis and structural collapse seen here. *Osteoarthritis secondary to joint incongruity* - **Osteoarthritis** is a common consequence of chronic joint incongruity or damage, including that caused by AVN; however, it is a **secondary process** rather than the primary underlying pathology in this scenario. - The **crescent sign** and specific pattern of articular collapse point to AVN as the initiating event, with osteoarthritis developing later. *Stress fracture of the femoral neck* - A **stress fracture** typically presents as pain in the femoral neck, often with a different radiological appearance, such as a **linear lucency** or sclerosis. - It would not typically cause a **crescent sign** or the widespread collapse of the femoral head articular surface characteristic of avascular necrosis.

Question 114: An 81-year-old man with severe aortic stenosis (valve area 0.7 cm², mean gradient 52 mmHg) and NYHA class III heart failure sustains a displaced intracapsular neck of femur fracture. His cardiologist states he is not a candidate for valve replacement due to frailty and comorbidities. The patient was independently mobile pre-injury using a frame. Which surgical option represents the best balance of risk and functional outcome?

A. Non-operative management with early mobilization
B. Cannulated screw fixation under local anaesthesia
C. Cemented hemiarthroplasty under general anaesthesia
D. Uncemented hemiarthroplasty under spinal anaesthesia (Correct Answer)
E. Total hip replacement under regional anaesthesia

Explanation: ***Uncemented hemiarthroplasty under spinal anaesthesia***- This approach avoids **bone cement implantation syndrome (BCIS)**, which can cause sudden reductions in systemic vascular resistance and catastrophic **cardiovascular collapse** in patients with fixed cardiac output from **aortic stenosis**.- **Spinal anaesthesia** is often preferred in high-risk cardiac patients to avoid the haemodynamic fluctuations associated with **general anaesthesia** and positive pressure ventilation.*Non-operative management with early mobilization*- This leads to extremely high **morbidity and mortality** in mobile patients due to complications of immobility like **pressure sores**, **pneumonia**, and **venous thromboembolism**.- It does not address the severe pain of a **displaced fracture**, preventing any meaningful functional mobilization.*Cannulated screw fixation under local anaesthesia*- **Cannulated screws** have a very high failure rate, including **non-union** and **avascular necrosis**, in displaced intracapsular fractures of the elderly.- While less invasive, it provides insufficient stability for **immediate weight-bearing**, which is essential for surviving a hip fracture at age 81.*Cemented hemiarthroplasty under general anaesthesia*- Cementing is typically preferred for better fixation, but the risk of **BCIS** is critically high in a patient with a **valve area of 0.7 cm²** and heart failure.- **General anaesthesia** and cement-induced hypotension can lead to fatal **myocardial ischemia** or arrest in the setting of severe, fixed-obstruction **aortic stenosis**.*Total hip replacement under regional anaesthesia*- **Total hip replacement** is an overly extensive procedure for a patient who was already using a **walking frame** pre-injury and has significant cardiac frailty.- It involves longer **operative time** and higher **blood loss**, which this patient's cardiovascular system cannot tolerate.

Question 115: A 62-year-old woman presents with a 5-month history of lower back pain radiating down the posterior aspect of her left leg to the heel. The pain is worse with prolonged sitting and improves with standing. She describes numbness over the lateral border of her left foot. On examination, she can walk on her heels but has difficulty walking on her toes on the left side. Ankle reflex is absent on the left. Which nerve root is most likely affected?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - The patient exhibits classic signs of **S1 radiculopathy**, including weakness in **plantarflexion** (difficulty walking on toes) and an **absent ankle reflex**. - Sensory findings such as numbness on the **lateral border of the foot** and pain radiating to the **heel** correspond specifically to the **S1 dermatome**. *L3* - **L3 nerve root** involvement typically causes pain and numbness in the **anterior thigh** and medial knee area. - It is associated with weakness in **hip flexion** or **knee extension**, rather than the distal foot findings seen here. *L4* - **L4 radiculopathy** presents with a **diminished knee (patellar) reflex** and pain radiating to the **medial malleolus**. - Primary motor weakness involves **foot inversion** and knee extension, but this patient can walk on her heels (dorsiflexion intact). *L5* - **L5 nerve root** compression typically results in weakness of **great toe extension** (extensor hallucis longus) and difficulty with **heel walking**. - It primarily affects sensation on the **dorsal surface** of the foot and does not involve the ankle reflex. *S2* - **S2 radiculopathy** is much less common and typically involves the **posterior thigh** and popliteal fossa rather than the heel. - It is more closely associated with **perineal sensation** and contributes to the **anal wink reflex** rather than the ankle reflex.

Question 116: A 70-year-old man undergoes total hip replacement for a displaced intracapsular neck of femur fracture. He has a history of recurrent venous thromboembolism and is on long-term warfarin with INR consistently in range (2.0-3.0). What is the most appropriate venous thromboembolism (VTE) prophylaxis regimen post-operatively?

A. Continue warfarin alone with target INR 2.0-3.0 (Correct Answer)
B. Stop warfarin and commence therapeutic dose low molecular weight heparin (LMWH)
C. Stop warfarin and commence prophylactic dose LMWH until mobile
D. Continue warfarin and add prophylactic dose LMWH
E. Stop warfarin, commence direct oral anticoagulant (DOAC) at prophylactic dose

Explanation: ***Continue warfarin alone with target INR 2.0-3.0*** - For patients already on **long-term therapeutic anticoagulation**, such as warfarin for recurrent VTE, continuing the established regimen post-operatively provides sufficient prophylaxis against new events. - NICE guidelines (NG89) specify that adding pharmacological prophylaxis (like LMWH) to an existing therapeutic dose is unnecessary and significantly increases the **risk of bleeding**. *Stop warfarin and commence therapeutic dose low molecular weight heparin (LMWH)* - While therapeutic LMWH is used for **bridging** perioperatively, it is not the standard long-term prophylaxis for someone already stable and established on warfarin. - Switching unnecessarily to long-term LMWH is more invasive for the patient and does not offer superior protection compared to resume **warfarin therapy**. *Stop warfarin and commence prophylactic dose LMWH until mobile* - Transitioning from therapeutic warfarin to a **prophylactic dose** of LMWH would result in sub-therapeutic anticoagulation levels. - In a patient with a history of **recurrent VTE**, reducing the intensity of anticoagulation increases the risk of a thromboembolic event during the high-risk post-orthopedic period. *Continue warfarin and add prophylactic dose LMWH* - Combining **therapeutic warfarin** (INR 2.0-3.0) with LMWH exceeds the required anticoagulation for VTE prevention. - This combination significantly elevates the risk of **post-operative hematoma** and surgical site bleeding without providing extra clinical benefit. *Stop warfarin, commence direct oral anticoagulant (DOAC) at prophylactic dose* - **DOACs** are effective for VTE prophylaxis, but there is no clinical indication to switch a patient from stable warfarin to a different agent post-surgery. - Prescribing a DOAC at a **prophylactic dose** would provide less protection than the patient’s baseline therapeutic INR, heightening the risk of recurrent clots.

Question 117: A 51-year-old woman with metastatic breast cancer presents with a 3-week history of thoracic back pain and new onset difficulty walking. On examination, she has a sensory level at T8, grade 3/5 power in both legs, and brisk knee and ankle reflexes. Bladder scan shows 400 mL residual volume post-void. She was due to start radiotherapy next week. What is the most appropriate immediate management?

A. Commence dexamethasone 16 mg daily and arrange radiotherapy within 24 hours
B. Arrange MRI spine and start dexamethasone after imaging
C. Contact neurosurgery for urgent decompression and start dexamethasone immediately (Correct Answer)
D. Start dexamethasone, insert catheter, and arrange routine MRI within 1 week
E. Arrange emergency CT myelogram and start dexamethasone

Explanation: ***Contact neurosurgery for urgent decompression and start dexamethasone immediately***- The patient exhibits features of **Malignant Spinal Cord Compression (MSCC)**, including thoracic level sensory loss, **motor deficit (3/5 power)**, and urinary retention, which constitutes an **oncological emergency**.- Urgent **surgical decompression** followed by radiotherapy is superior to radiotherapy alone for patients with significant motor deficits, spinal instability, or single-level compression to preserve neurological function.*Commence dexamethasone 16 mg daily and arrange radiotherapy within 24 hours*- While high-dose **dexamethasone** is a standard initial step to reduce vasogenic edema, radiotherapy alone is less effective than surgery for patients already showing **neurological deficits**.- Radiotherapy is generally reserved as primary treatment for highly **radiosensitive tumors** (e.g., lymphomas) or patients who are functionally unfit for surgery.*Arrange MRI spine and start dexamethasone after imaging*- **Dexamethasone** should be administered **immediately** upon clinical suspicion of spinal cord compression to prevent further deterioration, without waiting for imaging results.- Although **MRI whole spine** is the gold standard for diagnosis, the clinical presentation of motor weakness requires parallel surgical consultation rather than serial steps.*Start dexamethasone, insert catheter, and arrange routine MRI within 1 week*- A one-week delay is inappropriate and dangerous; imaging for suspected MSCC must be performed **urgently (within 24 hours)** to avoid irreversible paralysis.- Management of **urinary retention** via catheterization is necessary, but the priority is addressing the **mechanical compression** of the spinal cord.*Arrange emergency CT myelogram and start dexamethasone*- **MRI Whole Spine** is the definitive imaging modality of choice; a **CT myelogram** is only indicated if MRI is contraindicated (e.g., non-compatible pacemakers).- While starting dexamethasone is correct, the management must include a referral for surgical intervention given the **acute neurological decline**.

Question 118: A 68-year-old woman sustains a basicervical neck of femur fracture. Pre-injury she was independently mobile with a walking stick. She has a history of osteoporosis, chronic kidney disease stage 3b (eGFR 38 mL/min/1.73m²), and well-controlled heart failure. Which surgical management option is most appropriate?

A. Cannulated screw fixation
B. Dynamic hip screw fixation (Correct Answer)
C. Uncemented hemiarthroplasty
D. Cemented total hip replacement
E. Proximal femoral nail

Explanation: ***Dynamic hip screw fixation*** - **Basicervical neck of femur** fractures occur at the junction of the neck and the trochanter; they are biomechanically equivalent to **extracapsular** fractures and require stable internal fixation. - **Dynamic hip screw (DHS)** is the gold standard for these fractures as it allows controlled collapse and compression across the fracture line while maintaining stability. *Cannulated screw fixation* - These are typically reserved for **undisplaced intracapsular** fractures; they provide insufficient stability for the high-shear forces seen in **basicervical** patterns. - Basicervical fractures have a significantly higher rate of **fixation failure** and non-union when using cannulated screws compared to a DHS. *Uncemented hemiarthroplasty* - Arthroplasty is indicated for **displaced intracapsular** fractures where the blood supply to the femoral head is compromised, which is not the primary concern in **extracapsular/basicervical** fractures. - **Internal fixation** is preferred over joint replacement in this patient to preserve the native bone and avoid the higher surgical trauma of hemiarthroplasty. *Cemented total hip replacement* - While suitable for active patients with displaced intracapsular fractures, it is not the standard of care for **basicervical** fractures where the femoral head blood supply remains intact. - The patient’s **CKD stage 3b** and heart failure increase the risk of **Bone Cement Implantation Syndrome**, making fixation a safer choice than a major cemented arthroplasty. *Proximal femoral nail* - **Intramedullary nails** are generally preferred for unstable, reverse oblique, or high subtrochanteric fractures rather than simple basicervical patterns. - A **DHS** is cheaper and has a lower profile, making it the preferred first-line treatment for stable **extracapsular** patterns over intramedullary nailing.

Question 119: A 43-year-old man with a 6-month history of chronic lower back pain and morning stiffness lasting over 90 minutes presents with new onset right heel pain. He mentions having had three episodes of acute unilateral red eye in the past two years. Examination reveals reduced lumbar spine flexion (Schober's test: 3 cm expansion from 15 cm). Blood tests show CRP 42 mg/L, ESR 38 mm/hr, and he is HLA-B27 positive. What is the most appropriate initial imaging investigation for his back pain?

A. Plain radiograph of lumbar spine and pelvis
B. MRI of lumbar spine
C. CT scan of sacroiliac joints
D. MRI of sacroiliac joints and spine (Correct Answer)
E. Bone scintigraphy

Explanation: ***MRI of sacroiliac joints and spine*** - The patient's presentation with chronic inflammatory back pain, morning stiffness >90 minutes, new heel pain (**enthesitis**), recurrent unilateral red eye (**anterior uveitis**), reduced lumbar flexion, elevated inflammatory markers, and **HLA-B27 positivity** are highly suggestive of **axial spondyloarthritis**. - **MRI** is the most sensitive imaging modality for detecting early **sacroiliitis** (bone marrow edema, erosions) and active inflammation in the spine, which is crucial for early diagnosis and appropriate management. *Plain radiograph of lumbar spine and pelvis* - **Plain radiographs** are often normal in the early stages of axial spondyloarthritis and only show changes like **sacroiliitis** or **syndesmophytes** after significant structural damage has occurred, often years into the disease. - Relying solely on X-rays can delay diagnosis and intervention, despite strong clinical suspicion and inflammatory markers. *MRI of lumbar spine* - While an **MRI of the lumbar spine** can show spinal inflammation, it is not the initial imaging of choice because the **sacroiliac joints** are the primary site of involvement and diagnostic hallmark in axial spondyloarthritis. - Missing the sacroiliac joints would fail to fully evaluate the extent of the disease and meet the **ASAS classification criteria** for axial spondyloarthritis. *CT scan of sacroiliac joints* - **CT scans** provide excellent detail of bone structure and are good for identifying **erosions** and **sclerosis** in sacroiliac joints, but they are less sensitive than MRI for detecting early **active inflammation** (bone marrow edema). - Additionally, CT involves **ionizing radiation**, making MRI generally preferred for initial assessment of inflammatory activity. *Bone scintigraphy* - **Bone scintigraphy** can detect areas of increased bone turnover, but it has low **specificity** for diagnosing axial spondyloarthritis, as many conditions can cause increased uptake. - It offers poor anatomical resolution compared to MRI and is rarely used as a primary diagnostic tool for these conditions.

Question 120: A 75-year-old man with an intertrochanteric neck of femur fracture undergoes dynamic hip screw fixation. Post-operatively, which measurement on the anteroposterior hip radiograph best predicts the stability of the fixation and risk of cut-out of the lag screw?

A. The length of the lag screw penetrating the femoral head
B. The tip-apex distance (TAD) (Correct Answer)
C. The angle between the lag screw and the side plate
D. The number of cortices engaged by the side plate screws
E. The distance from the lag screw tip to the articular surface

Explanation: ***The tip-apex distance (TAD)*** - **TAD** is the single most important radiographic predictor of **lag screw cut-out**; it is the sum of the distances from the screw tip to the femoral head apex on both AP and lateral views. - A **TAD greater than 25 mm** is significantly associated with mechanical failure and superior-lateral migration of the screw through the femoral head. *The length of the lag screw penetrating the femoral head* - While the screw must be long enough to obtain **adequate purchase** in the subchondral bone, length alone does not account for the **three-dimensional positioning**. - Total length is less predictive of failure than the distance relative to the **center of the femoral head apex**. *The angle between the lag screw and the side plate* - Most dynamic hip screws use a fixed angle (typically **135 or 150 degrees**), which helps restore the femoral neck-shaft angle but does not directly predict **screw cut-out**. - While incorrect angulation can lead to **malalignment**, it is secondary to the precision of the screw tip placement within the head. *The number of cortices engaged by the side plate screws* - Cortical engagement is vital for the **stability of the side plate** to the femoral shaft to prevent plate pull-off. - This measurement does not address the risk of the **lag screw** cutting through the **trabecular bone** of the femoral head. *The distance from the lag screw tip to the articular surface* - Although the screw tip should ideally be within **5-10 mm** of the joint surface, this single-plane measurement is less comprehensive than the **TAD**. - TAD provides a more reliable assessment by combining measurements from both the **anteroposterior and lateral** radiographs.

Question 121: A 57-year-old man with prostate cancer presents with a 4-week history of progressive lower back pain, worse at night. He reports new onset difficulty initiating urination and constipation. On examination, he has tenderness over T12-L1, and lower limb neurology reveals hyperreflexia with bilateral upgoing plantars. Perianal sensation is intact. What is the most likely level of pathology?

A. Cauda equina compression below L2
B. Conus medullaris compression at T12-L2 (Correct Answer)
C. Lumbar nerve root compression at L4-L5
D. Thoracic spinal cord compression at T10-T11
E. Sacral nerve compression at S2-S4

Explanation: ***Conus medullaris compression at T12-L2*** - The presence of **hyperreflexia** and **bilateral upgoing plantars** signifies **Upper Motor Neuron (UMN)** involvement, which points to compression of the spinal cord itself. - The **T12-L1 tenderness** along with early **bladder dysfunction** (difficulty initiating urination) and **constipation** are classic symptoms of **Conus Medullaris Syndrome**, as the conus is located between T12 and L2 vertebral levels. *Cauda equina compression below L2* - This condition is characterized by **Lower Motor Neuron (LMN)** signs, including **hyporeflexia** or areflexia, flaccid paralysis, and often **saddle anesthesia** (loss of perianal sensation). - The patient's **hyperreflexia** and **intact perianal sensation** contradict a cauda equina syndrome. *Lumbar nerve root compression at L4-L5* - Compression at this level would primarily cause **radicular pain**, focal weakness, and sensory deficits corresponding to the affected **nerve root**, typically L5. - It would not result in **hyperreflexia**, **upgoing plantars**, or significant early **bladder/bowel dysfunction** like that observed in this patient. *Thoracic spinal cord compression at T10-T11* - While compression in the thoracic spine would produce **UMN signs**, the specific **tenderness at T12-L1** and the pattern of sphincter involvement strongly favor a more caudal spinal cord lesion. - Higher thoracic compression would typically present with a distinct **sensory level** and often more profound motor deficits before significant sphincter symptoms. *Sacral nerve compression at S2-S4* - Isolated sacral nerve compression presents with **LMN signs**, typically causing **flaccid bladder** or bowel dysfunction, and **perianal sensory loss** (saddle anesthesia). - This diagnosis does not account for the **hyperreflexia** and **upgoing plantars**, which indicate **UMN involvement** of the spinal cord.

Question 122: What is the mechanism by which the medial circumflex femoral artery is most commonly injured during a displaced intracapsular neck of femur fracture?

A. Direct laceration by bone fragments
B. Thrombosis due to increased intra-articular pressure and capsular tamponade
C. Spasm secondary to local inflammatory mediators
D. Compression by haematoma formation
E. Stretching and tearing due to displacement and rotation (Correct Answer)

Explanation: ***Stretching and tearing due to displacement and rotation*** - In a **displaced intracapsular neck of femur fracture**, the **medial circumflex femoral artery (MCFA)**, particularly its **retinacular branches**, is directly injured by the mechanical forces of fracture displacement and rotation of the femoral head. - This **mechanical disruption**, stretching, and tearing of these critical vessels, which are the primary blood supply to the femoral head, is the leading cause of **avascular necrosis**. *Direct laceration by bone fragments* - While possible, **direct laceration** by sharp bone fragments is less common than the diffuse **stretching and tearing** of the retinacular vessels, which are numerous and delicate. - The primary mechanism of injury involves the disruption of the vessel's integrity as the femoral neck and head fragment move relative to each other, not typically a sharp cut. *Thrombosis due to increased intra-articular pressure and capsular tamponade* - **Increased intra-articular pressure** from **haemarthrosis** and subsequent **capsular tamponade** can compromise microvascular flow and exacerbate ischemia. - However, this is a **secondary effect** that contributes to further ischemia, not the primary mechanism by which the MCFA itself is initially injured during the fracture event. *Spasm secondary to local inflammatory mediators* - **Vascular spasm** can occur in response to trauma and inflammatory mediators, potentially reducing blood flow temporarily. - Nevertheless, spasm is not the primary mechanism causing the **permanent structural damage** to the MCFA and its branches that leads to **avascular necrosis** in these fractures. *Compression by haematoma formation* - A **haematoma** within the joint capsule can indeed compress smaller vessels and contribute to ischemia. - However, the initial and most significant injury to the **medial circumflex femoral artery** in a displaced fracture is typically a direct mechanical **stretching and tearing**, rather than compression from a forming haematoma.

Question 123: A 38-year-old woman presents to the Emergency Department with sudden onset severe lower back pain and inability to pass urine for 12 hours. She has bilateral leg weakness and numbness in the perineal region. On examination, anal tone is reduced and there is saddle anaesthesia. What is the most appropriate immediate management?

A. Arrange urgent MRI spine within 24 hours and refer to physiotherapy
B. Prescribe oral prednisolone and arrange outpatient MRI
C. Insert urinary catheter, arrange emergency MRI, and contact neurosurgery/spinal team immediately (Correct Answer)
D. Arrange CT lumbar spine and admit for bed rest
E. Commence high-dose NSAIDs and arrange urgent orthopaedic outpatient review

Explanation: ***Insert urinary catheter, arrange emergency MRI, and contact neurosurgery/spinal team immediately*** - This patient presents with hallmark signs of **Cauda Equina Syndrome (CES)**, including **urinary retention**, **saddle anesthesia**, and **reduced anal tone**, which constitutes a surgical emergency. - Immediate management requires **emergency MRI** to confirm compression and urgent **neurosurgical/spinal consultation** for decompression to prevent permanent neurological deficits. *Arrange urgent MRI spine within 24 hours and refer to physiotherapy* - A "within 24 hours" timeframe is insufficient for suspected CES, which requires **emergency imaging** and intervention ideally as soon as possible to optimize recovery. - **Physiotherapy** is an inappropriate primary referral for an acute cord/cauda equina compression where surgical intervention is the priority. *Prescribe oral prednisolone and arrange outpatient MRI* - **Outpatient MRI** is dangerously slow for CES, as neurological damage can become **irreversible** within hours. - While steroids are used for **Malignant Spinal Cord Compression (MSCC)**, they are not the definitive treatment for mechanical causes of CES like a massive disc prolapse. *Arrange CT lumbar spine and admit for bed rest* - **MRI** is the gold standard imaging modality because **CT** provides poor visualization of soft tissues, nerve roots, and the extent of canal compromise. - **Bed rest** alone is a passive management strategy that fails to address the underlying physical compression of the **cauda equina**. *Commence high-dose NSAIDs and arrange urgent orthopaedic outpatient review* - **NSAIDs** are for symptomatic relief of simple back pain and are entirely inadequate for the profound **neurological compromise** seen in this patient. - **Outpatient review** is an inappropriate delay for a condition that requires **emergency decompression surgery** to save bladder and bowel function.

Question 124: A 74-year-old woman undergoes cannulated screw fixation for an undisplaced Garden II intracapsular neck of femur fracture. On day 2 post-operatively, she develops sudden onset shortness of breath, confusion, and a petechial rash across her chest and axillae. Her oxygen saturation is 89% on room air. Blood tests show: Hb 95 g/L (from 125 g/L pre-operatively), platelets 82 × 10⁹/L (from 245 × 10⁹/L). What is the most likely diagnosis?

A. Pulmonary embolism
B. Fat embolism syndrome (Correct Answer)
C. Bone cement implantation syndrome
D. Acute myocardial infarction
E. Hospital-acquired pneumonia

Explanation: ***Fat embolism syndrome***- This patient presents with the classic Gurd's triad: **respiratory insufficiency** (hypoxia), **neurological impairment** (confusion), and a pathognomonic **petechial rash** in the axillae and chest.- Lab findings such as sudden **thrombocytopenia** and a drop in **haemoglobin** are supporting features that occur within 24-72 hours of long bone or pelvic fractures.*Pulmonary embolism*- While it causes sudden **shortness of breath** and hypoxia, it does not typically present with a **petechial rash** or acute **thrombocytopenia**.- It is less likely to cause sudden-onset **confusion** as a primary symptom unless it leads to severe obstructive shock.*Bone cement implantation syndrome*- This syndrome occurs **intraoperatively** during the pressurization of bone cement, whereas this patient had **cannulated screw fixation** (no cement used).- Characteristics include sudden cardiovascular collapse, hypotension, and hypoxia at the time of **cement insertion**, not days later.*Acute myocardial infarction*- Heart attacks can present with shortness of breath, but they do not account for the **petechial rash**, **confusion**, or sudden drop in **platelets**.- The postoperative timing (24-72 hours) and specific multi-system involvement point more specifically to **embolic phenomena** related to the fracture.*Hospital-acquired pneumonia*- Pneumonia typically presents with **productive cough**, **fever**, and consolidation on imaging, usually developing slightly later in the hospital stay.- It cannot explain the distinct **petechial rash** or the systemic **haematological changes** seen in this case.

Question 125: A 66-year-old woman presents with a 3-month history of lower back pain and bilateral leg pain worse on walking. She reports that the pain improves when she leans forward on a shopping trolley. She has no night pain, no bladder or bowel disturbance, and no weight loss. Neurological examination reveals normal power, sensation, and reflexes. What is the most likely diagnosis?

A. Lumbar disc herniation
B. Cauda equina syndrome
C. Spinal stenosis (Correct Answer)
D. Ankylosing spondylitis
E. Malignant spinal cord compression

Explanation: ***Spinal stenosis*** - This patient presents with classic **neurogenic claudication**, where bilateral leg pain is triggered by walking and relieved by spine flexion, often called the **'shopping trolley sign'**. - Forward flexion increases the **spinal canal diameter**, reducing pressure on nerve roots caused by degenerative changes like **ligamentum flavum hypertrophy** or facet joint arthropathy. *Lumbar disc herniation* - Typically presents with **acute onset** unilateral radicular pain (sciatica) that is often worsened by sitting or forward flexion, rather than relieved by it. - Physical examination usually reveals a positive **straight leg raise test** and specific dermatomal or myotomal deficits, which are absent here. *Cauda equina syndrome* - A surgical emergency characterized by **saddle anesthesia**, new-onset **urinary retention** or fecal incontinence, and significant bilateral neurological deficits. - The absence of **bladder/bowel disturbance** and a normal neurological exam effectively rule out this diagnosis. *Ankylosing spondylitis* - Usually presents in **younger patients** (under 45) with chronic inflammatory back pain and **morning stiffness** that improves with exercise. - It is associated with the **HLA-B27** gene and involves progressive spinal fusion rather than mechanical claudication symptoms. *Malignant spinal cord compression* - Characterized by **'red flag' symptoms** such as persistent night pain, unexplained weight loss, and a history of primary malignancy. - This patient lacks constitutional symptoms, and her pain is specifically related to **posture and walking** rather than being constant or nocturnal.

Question 126: Which of the following Garden classification stages for intracapsular neck of femur fractures has the highest risk of developing avascular necrosis of the femoral head?

A. Garden I - incomplete fracture, undisplaced
B. Garden II - complete fracture, undisplaced
C. Garden III - complete fracture, partially displaced
D. Garden IV - complete fracture, completely displaced (Correct Answer)
E. All Garden stages have equal risk

Explanation: ***Garden IV - complete fracture, completely displaced*** - This stage represents a total loss of contact between the fragments, leading to the highest degree of disruption to the **medial circumflex femoral artery** and retinacular vessels. - The significant displacement correlates with an **avascular necrosis (AVN)** risk of approximately 30-35%, the highest among all Garden categories. *Garden I - incomplete fracture, undisplaced* - These are **impacted or incomplete** fractures where the blood supply remains largely intact, resulting in a low AVN risk of about 5-10%. - The **trabeculae** are angulated but not completely disrupted, maintaining better physiological stability than higher stages. *Garden II - complete fracture, undisplaced* - While the fracture is complete, the lack of displacement means the **vascular supply** to the femoral head is generally preserved. - The risk of developing **avascular necrosis** is relatively low (10-15%) compared to displaced fracture patterns. *Garden III - complete fracture, partially displaced* - This stage involves partial displacement where the distal fragment is **externally rotated**, causing significant but incomplete vascular compromise. - Although the risk of **AVN** is high (20-30%), it is statistically lower than the total disruption seen in Stage IV. *All Garden stages have equal risk* - This statement is incorrect because the classification is specifically designed to predict the likelihood of **vascular impairment** based on displacement. - Clinical management differs significantly between stages because the risk of **non-union** and AVN increases progressively from Stage I to Stage IV.

Question 127: A 41-year-old man presents with a 2-week history of severe lower back pain and fevers. He has a past medical history of type 2 diabetes mellitus with poor glycaemic control. On examination, he has tenderness over the L3-L4 vertebrae and his temperature is 38.4°C. Blood tests show: WCC 16.2 × 10⁹/L, CRP 145 mg/L, ESR 78 mm/hr. What is the most appropriate initial imaging investigation?

A. Plain radiograph of lumbar spine
B. CT scan of lumbar spine
C. MRI scan of whole spine (Correct Answer)
D. Bone scintigraphy
E. Ultrasound-guided biopsy

Explanation: ***MRI scan of whole spine*** - **MRI** is the gold standard and most appropriate initial imaging because it has the highest sensitivity (96%) and specificity (93%) for detecting early **spinal infection** (discitis/osteomyelitis). - A **whole spine** scan is mandatory as it can identify **skip lesions**, localized **epidural abscesses**, and paraspinal collections that are not clinically apparent. *Plain radiograph of lumbar spine* - **Plain X-rays** have very low sensitivity in the acute phase, as bone destruction or **disc space narrowing** may not be visible for 2 to 4 weeks after symptoms start. - They often appear normal in the early presentation of **vertebral osteomyelitis**, delaying critical diagnosis. *CT scan of lumbar spine* - **CT scanning** provides excellent detail of **cortical bone destruction**, but it is significantly less sensitive than MRI for detecting early **marrow edema** and soft tissue involvement. - It is generally reserved for patients who have a **contraindication to MRI**, such as certain metallic implants or severe claustrophobia. *Bone scintigraphy* - **Technetium-99m bone scans** are sensitive to increased bone turnover but lack **anatomical specificity**, making it difficult to distinguish infection from degenerative changes or tumors. - This modality is rarely used as a first-line test when MRI is available due to the high rate of **false positives** in elderly populations. *Ultrasound-guided biopsy* - While a **biopsy** is essential for microbiological diagnosis and antibiotic sensitivity, it should be performed **after imaging** has localized the pathology. - Imaging must be obtained first to determine the **extent of the infection** and provide a safe anatomical window for the needle insertion.

Question 128: A 79-year-old woman sustains a displaced intracapsular neck of femur fracture. During preoperative assessment, she is found to have a serum creatinine of 180 μmol/L and an estimated glomerular filtration rate (eGFR) of 28 mL/min/1.73m². She is otherwise medically stable. Which surgical intervention should be performed?

A. Total hip replacement with uncemented components
B. Cemented hemiarthroplasty
C. Uncemented hemiarthroplasty (Correct Answer)
D. Cannulated screw fixation
E. Dynamic hip screw fixation

Explanation: ***Uncemented hemiarthroplasty***- For patients with significant **renal impairment** (eGFR of 28 mL/min/1.73m²), **uncemented** components are preferred to avoid the risk of **Bone Cement Implantation Syndrome (BCIS)**, which can cause severe cardiovascular instability.- **Hemiarthroplasty** is the standard treatment for a **displaced intracapsular neck of femur fracture** in a 79-year-old to ensure early mobilization and reduce the risk of **avascular necrosis** and non-union.*Total hip replacement with uncemented components*- **Total hip replacement (THR)** is typically reserved for **fitter, more active** elderly patients with good cognitive function and minimal comorbidities.- While uncemented avoids BCIS, a **hemiarthroplasty** is generally more appropriate for a 79-year-old with significant comorbidities like **chronic kidney disease** due to less operative time and surgical stress.*Cemented hemiarthroplasty*- **Cemented components** are often preferred in the elderly for immediate stability and reduced periprosthetic fracture risk, but the use of bone cement carries a risk of **BCIS**.- Given the patient's severe **renal impairment** (eGFR 28), the systemic effects of cement polymerization could lead to dangerous **cardiovascular compromise**, making cemented arthroplasty contraindicated.*Cannulated screw fixation*- **Cannulated screw fixation** is primarily indicated for **undisplaced** intracapsular femoral neck fractures or in younger, physiologically active patients.- In a 79-year-old with a **displaced fracture**, this method has a very **high failure rate** due to **non-union** and increased risk of **avascular necrosis** of the femoral head.*Dynamic hip screw fixation*- A **dynamic hip screw (DHS)** is the treatment of choice for **extracapsular** (intertrochanteric and subtrochanteric) fractures of the femur.- It is **not indicated** for **intracapsular fractures** because it does not protect the vascular supply to the femoral head, leaving a high risk of **avascular necrosis**.

Question 129: A 78-year-old man with Parkinson's disease sustains a minimally displaced basicervical neck of femur fracture after falling in his care home. His pre-injury mobility was limited to indoor walking with a frame, and he requires assistance with most activities of daily living. The orthopaedic team is considering the optimal surgical management. Which of the following factors makes a basicervical fracture biomechanically distinct from a typical intracapsular neck of femur fracture and influences surgical choice?

A. Higher risk of avascular necrosis due to disruption of retinacular blood supply
B. Greater tendency to displace into varus due to orientation outside the capsular attachment (Correct Answer)
C. Lower risk of non-union due to better blood supply than intracapsular fractures
D. Higher incidence of associated femoral shaft fracture requiring longer implants
E. Reduced risk of fixation failure due to increased bone density at the basicervical region

Explanation: ***Greater tendency to displace into varus due to orientation outside the capsular attachment*** - **Basicervical fractures** occur at the junction of the femoral neck and the **intertrochanteric region**, making them biomechanically unstable with a significant tendency toward **varus collapse**. - Because they are located at or just outside the **capsular attachment**, they lack the stabilizing effect of the joint capsule and often feature a **vertical fracture line**, necessitating robust fixation like a **Dynamic Hip Screw (DHS)**. *Higher risk of avascular necrosis due to disruption of retinacular blood supply* - Basicervical fractures actually have a **lower risk** of **avascular necrosis** compared to intracapsular fractures because they are distal to the main **retinacular vessels**. - The blood supply to the femoral head is more likely to be preserved as the fracture sparing the **medial circumflex femoral artery** branches. *Lower risk of non-union due to better blood supply than intracapsular fractures* - While the blood supply is better, these fractures have a **higher risk of mechanical failure** and non-union if treated with simple screws due to **high shear forces**. - Clinical outcomes for **non-union** in basicervical fractures are often related to **fixation stability** rather than just biological blood supply. *Higher incidence of associated femoral shaft fracture requiring longer implants* - There is no specific clinical association between **basicervical neck fractures** and concomitant **femoral shaft fractures**. - While **cephalomedullary nails** are an option, the choice is driven by fracture stability at the neck, not by a distal shaft injury risk. *Reduced risk of fixation failure due to increased bone density at the basicervical region* - The basicervical region does not possess **increased bone density**; in elderly patients with **Parkinson's disease**, the bone is typically **osteoporotic**. - These fractures actually have a **higher risk of fixation failure** (up to 30%) if managed with standard cannulated screws instead of more stable extracapsular-style constructs.

Question 130: A 64-year-old woman presents to the Emergency Department with a 36-hour history of severe lower back pain and urinary retention. She reports numbness in the perineal area and has noticed loss of sensation when wiping after using the toilet. On examination, there is reduced sensation in the S2-S4 dermatomes bilaterally, reduced anal tone, and a palpable bladder. Lower limb power and reflexes are normal. Post-void residual volume is 800 ml. What is the maximum acceptable time from presentation to definitive surgical decompression to optimize neurological outcome?

A. Within 6 hours of symptom onset
B. Within 24 hours of symptom onset
C. Within 48 hours of symptom onset (Correct Answer)
D. Within 72 hours of symptom onset
E. Within 1 week of symptom onset

Explanation: ***Within 48 hours of symptom onset***- Clinical evidence suggests that **surgical decompression** performed within **48 hours** of symptom onset is the critical window to optimize recovery of bladder, bowel, and sexual function.- This patient presents with **Cauda Equina Syndrome (CES)**, characterized by **saddle anesthesia**, urinary retention, and reduced **anal tone**, necessitating urgent intervention to prevent permanent neurological damage.*Within 6 hours of symptom onset*- While very early intervention is ideal, clinical studies do not show a statistically significant difference in outcomes for surgery under **6 hours** compared to the **48-hour** threshold.- This timeframe is often logistically impossible due to the time required for **MRI diagnosis** and surgical preparation.*Within 24 hours of symptom onset*- Decompression within **24 hours** is excellent and often targeted, but failing to meet this does not necessarily preclude a good outcome as long as it occurs within **48 hours**.- The literature reinforces the **48-hour window** as the primary prognostic divider for long-term neurological recovery.*Within 72 hours of symptom onset*- Waiting until **72 hours** is associated with significantly worse outcomes and a higher risk of **permanent bladder dysfunction**.- Surgical delay beyond the 48-hour mark is considered inadequate for a **surgical emergency** like CES.*Within 1 week of symptom onset*- Delaying surgery for a week would likely result in **permanent nerve root damage** and chronic disability.- CES is an **acute neurosurgical emergency**, and intervention after a week would only be for stabilization rather than functional recovery.

Question 131: A 67-year-old man sustains a subtrochanteric femur fracture following a fall from a ladder. He has a 10-year history of bisphosphonate therapy for osteoporosis following a previous vertebral compression fracture. Radiographs show a transverse fracture pattern at the subtrochanteric level with cortical thickening of the lateral femoral cortex. Which feature of this fracture pattern is most characteristic of an atypical femur fracture associated with long-term bisphosphonate use?

A. Fracture location in the subtrochanteric or diaphyseal region
B. Transverse or short oblique fracture orientation
C. Presence of medial cortical spike or beak (Correct Answer)
D. Cortical thickening (periosteal or endosteal) at the fracture site
E. Association with prodromal pain in the affected limb

Explanation: ***Presence of medial cortical spike or beak*** - A **medial cortical spike** (or beak) is a **pathognomonic major diagnostic criterion** for **atypical femur fractures (AFFs)** associated with bisphosphonate use. - It signifies a complete fracture with a distinct **medial flare** that helps differentiate AFFs from typical osteoporotic fractures. *Fracture location in the subtrochanteric or diaphyseal region* - This location is a **major diagnostic criterion** for AFFs but is less specific than a medial cortical spike. - It defines the general area (below the lesser trochanter to just above the supracondylar flare) but doesn't describe a unique morphological feature. *Transverse or short oblique fracture orientation* - This describes the **fracture morphology**, with an angle of **≤ 30 degrees**, often mimicking a stress fracture. - While a major criterion, it is not as unique to AFFs as the medial spike, as similar patterns can be seen in other trauma types. *Cortical thickening (periosteal or endosteal) at the fracture site* - **Cortical thickening**, particularly on the **lateral femoral cortex**, is often a **minor criterion** or a sign of prodromal stress reaction. - It can be seen as a "dreaded black line" indicating attempts at bone remodeling, but it's not the definitive fracture characteristic. *Association with prodromal pain in the affected limb* - **Prodromal pain** in the thigh or groin is a common **minor clinical feature** preceding AFFs in many patients. - However, it is a **subjective symptom** and not a radiographic characteristic of the fracture pattern itself.

Question 132: A 61-year-old woman with rheumatoid arthritis presents to her GP with a 6-week history of lower back pain and progressive bilateral leg weakness. She has been on long-term methotrexate and prednisolone for 15 years. On examination, there is global weakness in both lower limbs (power 3/5 throughout), with preserved reflexes and normal plantar responses. Sensation is intact. She is apyrexial. Blood tests show CRP 45 mg/L, ESR 68 mm/hr, normal white cell count. Which of the following is the most likely underlying cause of her presentation?

A. Metastatic spinal cord compression from undiagnosed malignancy
B. Atlantoaxial subluxation causing cervical myelopathy (Correct Answer)
C. Spinal infection (discitis/osteomyelitis) secondary to immunosuppression
D. Guillain-Barré syndrome presenting with ascending paralysis
E. Cauda equina syndrome from large central disc prolapse

Explanation: ***Atlantoaxial subluxation causing cervical myelopathy***- In patients with long-standing **rheumatoid arthritis**, inflammation and laxity of the **transverse ligament** can lead to **atlantoaxial subluxation**, causing **cervical cord compression**.- The presentation of **progressive bilateral leg weakness** with **preserved reflexes** and intact sensation is characteristic of **cervical myelopathy**, indicating an upper motor neuron lesion in the cervical spine.*Metastatic spinal cord compression from undiagnosed malignancy*- While possible in any elderly patient, spinal cord compression from malignancy usually presents with more **acute onset**, severe localized **bony pain**, and often **rapid neurological deterioration**.- The patient's **preserved reflexes** and lack of specific systemic malignancy symptoms (e.g., weight loss, night sweats) make this less likely than a complication directly related to her long-standing RA.*Spinal infection (discitis/osteomyelitis) secondary to immunosuppression*- Although the patient is **immunosuppressed** with methotrexate and prednisolone, which increases infection risk, she is **apyrexial** and has a normal white cell count.- Spinal infection typically causes severe **localized spinal pain**, often worse at night, and more pronounced systemic signs of infection like fever, although these can be blunted in immunosuppressed patients. The elevated ESR/CRP are non-specific and can be due to active RA.*Guillain-Barré syndrome presenting with ascending paralysis*- **Guillain-Barré syndrome** is an acute demyelinating polyneuropathy characterized by **areflexia** (absent reflexes) and often **ascending paralysis**, which is contrary to the patient's **preserved reflexes**.- The 6-week progressive course and the specific context of long-standing RA make a structural neurological complication of RA more likely than GBS.*Cauda equina syndrome from large central disc prolapse*- **Cauda equina syndrome** presents with **lower motor neuron signs**, including **flaccid paralysis**, **areflexia** (absent reflexes), and often **saddle anesthesia** or **bladder/bowel dysfunction**.- This patient has **preserved reflexes** and intact sensation, and no mention of bladder/bowel issues, making cauda equina syndrome an unlikely diagnosis. The leg weakness is also described as global rather than radicular.

Question 133: A 72-year-old woman undergoes a dynamic hip screw (DHS) fixation for a stable two-part intertrochanteric neck of femur fracture. Post-operatively, what is the most important radiographic measurement to assess optimal placement of the lag screw within the femoral head?

A. The lag screw should be positioned in the superior and anterior quadrant of the femoral head on AP and lateral views
B. The lag screw tip should be within 10 mm of the subchondral bone on both AP and lateral radiographs
C. The lag screw should be positioned in the inferior and posterior quadrant of the femoral head for maximum purchase
D. The barrel plate should be positioned at least 2 cm distal to the vastus ridge on the lateral femur
E. The tip-apex distance should be less than 25 mm when measured on AP and lateral radiographs (Correct Answer)

Explanation: ***The tip-apex distance should be less than 25 mm when measured on AP and lateral radiographs*** - The **tip-apex distance (TAD)** is the most critical radiographic measurement used to predict **lag screw cut-out** and fixation failure in intertrochanteric hip fractures. - A **TAD of less than 25 mm** indicates optimal screw placement, significantly reducing the risk of complications and promoting stable fracture healing. *The lag screw should be positioned in the superior and anterior quadrant of the femoral head on AP and lateral views* - Positioning the lag screw in the **superior-anterior quadrant** is associated with a higher risk of **screw cut-out** due to the relatively weaker bone in this region and unfavorable biomechanical forces. - Optimal placement for a dynamic hip screw (DHS) is typically in the **center-center** or **inferior-central** region of the femoral head on both AP and lateral views for maximum stability. *The lag screw tip should be within 10 mm of the subchondral bone on both AP and lateral radiographs* - While proximity to the **subchondral bone** (usually 5-10mm) is important to maximize bone purchase, it does not fully capture the three-dimensional stability of the screw. - This parameter is a component of good technique but is secondary to the **Tip-Apex Distance (TAD)**, which comprehensively assesses the lag screw's position relative to the femoral head apex. *The lag screw should be positioned in the inferior and posterior quadrant of the femoral head for maximum purchase* - While an **inferior position** on the AP view can be acceptable (inferior-center), a **posterior position** on the lateral view is generally suboptimal and can lead to eccentric loading and potential failure. - Optimal placement aims for a **central position** on the lateral view and often an **inferior-central** position on the AP view to achieve the best mechanical purchase and prevent cut-out. *The barrel plate should be positioned at least 2 cm distal to the vastus ridge on the lateral femur* - The position of the **barrel plate** on the femoral shaft primarily relates to the length of the plate and the stability of the fracture in the diaphyseal segment, not the stability of the lag screw within the femoral head. - This measurement is less critical for preventing **lag screw cut-out** compared to the precise placement of the lag screw itself within the femoral head.

Question 134: A 35-year-old man presents to the Emergency Department with sudden onset severe lower back pain that began 4 hours ago while lifting a heavy box at work. The pain radiates down the posterior aspect of his left leg to the lateral border of his foot. He has difficulty walking on his toes on the left side. On examination, there is reduced sensation over the lateral border and dorsum of the left foot, and weakness of plantarflexion on the left. Straight leg raise is positive at 30 degrees on the left. Which nerve root is most likely to be affected?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - Compression of the **S1 nerve root** typically occurs at the **L5-S1 disc** level and leads to weakness in **plantarflexion**, making it difficult for patients to **walk on their toes**. - Sensory loss occurs along the **lateral border of the foot** and posterior leg, often accompanied by a diminished or absent **Achilles tendon reflex**. *L3* - **L3 nerve root** compression typically presents with weakness in **hip flexion** and **knee extension** (quadriceps). - Sensory deficit is usually localized to the **anterior thigh**, and the **patellar reflex** may be diminished. *L4* - The **L4 nerve root** provides motor innervation for **knee extension** and sensation to the **medial shin** and medial malleolus. - A classic clinical finding for L4 pathology is a diminished **patellar reflex** (knee-jerk). *L5* - **L5 nerve root** compression results in weakness of **big toe extension** (extensor hallucis longus) and **foot dorsiflexion**, causing difficulty **walking on heels**. - Sensory loss is typically found on the **dorsum of the foot**, particularly in the **first web space** between the first and second toes. *S2* - Compression of the **S2 nerve root** is relatively rare and usually presents with sensory changes along the **posterior thigh** and calf. - It is more commonly associated with complex syndromes like **cauda equina syndrome** if bladder or bowel dysfunction is present.

Question 135: A 58-year-old woman with known metastatic breast cancer presents with a 5-week history of progressively worsening lower back pain. The pain is constant, unrelieved by rest, and wakes her from sleep. She has noticed some weakness in her legs over the past week, particularly when climbing stairs. On examination, there is tenderness over L3 vertebra, reduced power (4/5) in both lower limbs, brisk knee reflexes bilaterally, and upgoing plantars. Anal tone is normal. What is the most appropriate immediate management?

A. Admit for urgent MRI whole spine and commence high-dose dexamethasone (Correct Answer)
B. Arrange urgent outpatient MRI lumbar spine within 48 hours and follow-up in clinic
C. Commence oral analgesia and arrange routine oncology follow-up within 2 weeks
D. Request plain radiographs of lumbar spine to assess for pathological fracture
E. Arrange urgent CT lumbar spine to identify the site of spinal metastasis

Explanation: ***Admit for urgent MRI whole spine and commence high-dose dexamethasone*** - This patient presents with clear signs of **Metastatic Spinal Cord Compression (MSCC)**, an oncological emergency characterized by **progressive back pain**, **motor weakness**, and **upper motor neuron signs** (brisk reflexes, upgoing plantars). - Immediate management requires **high-dose dexamethasone** to reduce peritumoural edema and an **urgent MRI of the whole spine** (within 24 hours), as skip lesions can occur in up to 20% of cases. *Arrange urgent outpatient MRI lumbar spine within 48 hours and follow-up in clinic* - Outpatient management is inappropriate for suspected **MSCC**, as it is an emergency that can lead to irreversible paralysis if not treated promptly. - Imaging only the **lumbar spine** is insufficient; a **whole spine MRI** is crucial to identify all sites of compression, including potential skip lesions. *Commence oral analgesia and arrange routine oncology follow-up within 2 weeks* - Delaying definitive management for two weeks in a patient with **progressive neurological deficits** and alarming pain features risks permanent loss of motor function and bowel/bladder control. - While **analgesia** is important for comfort, it does not address the underlying **spinal cord compression** which requires immediate investigation and treatment. *Request plain radiographs of lumbar spine to assess for pathological fracture* - **Plain radiographs** have very low sensitivity for detecting spinal cord compression and cannot visualize the spinal cord or degree of **thecal sac compromise**. - A normal X-ray does not rule out **MSCC** and should never delay the definitive gold-standard investigation, which is an **MRI**. *Arrange urgent CT lumbar spine to identify the site of spinal metastasis* - **CT scans** are excellent for evaluating bony pathology but are significantly less sensitive than **MRI** for visualizing **soft tissue masses** and the spinal cord itself. - Relying on a **CT lumbar spine** may miss the actual level of compression or additional sites of disease, especially since upper motor neuron signs often indicate a lesion above the lumbar spine.

Question 136: What is the approximate incidence of deep vein thrombosis in patients with neck of femur fractures who do not receive thromboprophylaxis?

A. 5-10%
B. 15-20%
C. 30-40%
D. 50-60% (Correct Answer)
E. 70-80%

Explanation: ***50-60%***- In the absence of **thromboprophylaxis**, the incidence of **Deep Vein Thrombosis (DVT)** in patients with **neck of femur fractures** is extremely high, ranging between 50-60%.- This elevated risk is driven by **Virchow's Triad**, specifically **venous stasis** from immobility and the **hypercoagulable state** triggered by trauma and major orthopedic surgery.*5-10%*- This range significantly underestimates the risk in high-risk orthopedic surgeries and is more characteristic of low-risk minor procedures.- At this low level, the clinical urgency for mandatory **pharmacological prophylaxis** (like LMWH) would not be as critical as it is for hip fractures.*15-20%*- While this reflects a higher risk than general surgery, it still falls short of the true incidence seen in untreated **proximal femur fractures**.- This percentage is closer to the risk observed in some medical patients with **congestive heart failure** or severe respiratory disease, rather than major orthopedic trauma.*30-40%*- This range is more typical for patients undergoing **total knee replacement** or elective hip arthroplasty without prophylaxis, rather than fracture patients.- **Neck of femur fracture** patients often have higher risks due to the immediate **endothelial injury** from the trauma itself and delayed time to surgery.*70-80%*- Although the risk is very high, an incidence of 70-80% is generally considered an overestimation for **venographic DVT** in standard clinical studies of hip fractures.- Most clinical literature and guidelines, such as **NICE**, benchmark the untreated risk at approximately 50-60% for DVT and 2-5% for **fatal pulmonary embolism**.

Question 137: A 70-year-old man sustains an undisplaced Garden I intracapsular neck of femur fracture following a fall. He is an active man who plays golf regularly and lives independently. He has no significant past medical history. The orthopaedic team decides to proceed with internal fixation using cannulated screws. In which configuration should the cannulated screws ideally be inserted to provide optimal biomechanical stability?

A. Three screws in a triangular configuration with the apex positioned inferiorly (Correct Answer)
B. Two screws positioned parallel to each other in the sagittal plane
C. Three screws in a triangular configuration with the apex positioned posteriorly
D. Four screws in a square configuration to maximize bone purchase
E. Three screws in a vertical linear arrangement along the femoral neck axis

Explanation: ***Three screws in a triangular configuration with the apex positioned inferiorly***- For **Garden I fractures**, three parallel screws in an **inverted triangle** pattern provide optimal biomechanical stability by maximizing the **moment arm** and resistance to shear forces.- Placing the **apex screw inferiorly** (resting on the calcar) and the other two superiorly ensures superior **rotational stability** and compression across the fracture site.*Two screws positioned parallel to each other in the sagittal plane*- Using only two screws provides significantly less **rotational control** and is biomechanically inferior for resisting **varus forces** compared to three screws.- Clinical guidelines generally recommend a minimum of three screws for stable internal fixation of **intracapsular femoral neck** fractures.*Three screws in a triangular configuration with the apex positioned posteriorly*- This configuration does not provide the same level of **coronal plane stability** as the inverted triangle with the apex inferiorly.- The apex screw must be positioned against the **inferior cortex (calcar)** to provide the strongest support against weight-bearing stresses.*Four screws in a square configuration to maximize bone purchase*- While a fourth screw may be used in **basicervical fractures**, it is not standard for subcapital fractures as it increases the risk of **femoral head devascularization**.- Adding a fourth screw overcrowding the femoral head can lead to iatrogenic damage without providing a significant increase in **mechanical strength**.*Three screws in a vertical linear arrangement along the femoral neck axis*- A linear arrangement offers very poor resistance to **rotational torque**, which is crucial for preventing fracture displacement during movement.- The lack of **divergence/triangulation** in the screw placement limits the ability to counteract multi-planar forces acting on the hip joint.

Question 138: A 47-year-old woman presents with a 12-week history of lower back pain and stiffness. She describes the pain as worst first thing in the morning, with stiffness lasting approximately 90 minutes that improves with exercise. She also reports pain in both heels when she first stands. On examination, there is reduced lumbar spine flexion with a Schober's test measurement of 3 cm (normal >5 cm). Which of the following investigation findings would be most specific for confirming the suspected underlying diagnosis?

A. Raised serum C-reactive protein and erythrocyte sedimentation rate
B. Sacroiliitis demonstrated on plain radiographs of the pelvis (Correct Answer)
C. Positive HLA-B27 antigen on genetic testing
D. Reduced lumbar spine bone mineral density on DEXA scanning
E. Bamboo spine appearance on lateral lumbar spine radiograph

Explanation: ***Sacroiliitis demonstrated on plain radiographs of the pelvis*** - This is the **hallmark radiological finding** in ankylosing spondylitis and is a key diagnostic criterion in the **Modified New York Criteria** for definite AS. - Early changes include **erosions**, **sclerosis**, and eventually **fusion** of the sacroiliac joints, confirming axial involvement. *Raised serum C-reactive protein and erythrocyte sedimentation rate* - While **inflammatory markers** (CRP, ESR) are often elevated in active ankylosing spondylitis, they are **nonspecific** and can be raised in many other inflammatory or infectious conditions. - A significant proportion (up to 50%) of patients with active AS may have **normal inflammatory markers**, making them unsuitable as a specific diagnostic test. *Positive HLA-B27 antigen on genetic testing* - **HLA-B27** is strongly associated with ankylosing spondylitis, being present in about 90% of patients, but its **specificity is low** as it is also found in 5-10% of the general population without AS. - Therefore, a positive result supports the diagnosis in the right clinical context but is **not diagnostic on its own** and not as specific as radiographic sacroiliitis. *Reduced lumbar spine bone mineral density on DEXA scanning* - **Osteoporosis** and osteopenia are common complications in ankylosing spondylitis, often due to chronic inflammation, reduced mobility, and sometimes corticosteroid use. - However, reduced **bone mineral density** is a secondary finding and not a specific diagnostic feature for the initial confirmation of ankylosing spondylitis itself. *Bamboo spine appearance on lateral lumbar spine radiograph* - The "bamboo spine" appearance is a characteristic feature of **advanced ankylosing spondylitis**, resulting from extensive **syndesmophyte formation** and fusion of vertebral bodies. - While highly specific, this finding typically occurs in **late-stage disease** and is unlikely to be present in a patient with a 12-week history, making it less relevant for initial confirmation.

Question 139: An 81-year-old woman sustains a displaced intracapsular neck of femur fracture. She has severe dementia with an Abbreviated Mental Test Score of 2/10 and was living in a nursing home with full care prior to admission. She has multiple comorbidities including chronic kidney disease stage 4, congestive heart failure, and previous stroke with residual right-sided weakness. The orthogeriatric team is considering whether surgery is appropriate. Which of the following factors is the strongest relative indication for non-operative management in this patient?

A. The presence of severe cognitive impairment with AMTS of 2/10
B. Complete loss of independent mobility prior to the fracture (Correct Answer)
C. Chronic kidney disease stage 4 with estimated GFR of 22 ml/min
D. Advanced age of 81 years at time of fracture
E. Previous stroke with residual hemiparesis

Explanation: ***Complete loss of independent mobility prior to the fracture*** - The primary goal of hip fracture surgery is to restore **functional mobility**; if a patient was already bed-bound or chair-bound, the functional benefit of surgery is virtually non-existent. - **NICE guidelines** suggest that non-operative management is mostly reserved for those who are medically unfit for any anesthesia or those whose pre-injury **non-ambulatory status** makes surgical risks outweigh clinical benefits. *The presence of severe cognitive impairment with AMTS of 2/10* - **Dementia** is not a contraindication to surgery; in fact, surgery often facilitates better pain management and nursing care in this population to prevent **delirium**. - Studies indicate that patients with cognitive impairment still benefit from **early mobilization** and stabilization of the fracture to reduce the risk of pressure sores. *Chronic kidney disease stage 4 with estimated GFR of 22 ml/min* - While **CKD stage 4** increases the risk of perioperative complications like electrolyte imbalances, it is a manageable **comorbidity** rather than a reason to omit surgery. - Multidisciplinary care involving an **orthogeriatrician** and renal specialist can optimize the patient for a safe surgical outcome. *Advanced age of 81 years at time of fracture* - **Chronological age** is not a relative indication for non-operative management; physiological status and **frailty** are more pertinent factors. - Many patients in their 80s and 90s undergo successful **hemiarthroplasty** or internal fixation, maintaining their pre-morbid quality of life. *Previous stroke with residual hemiparesis* - **Residual weakness** from a stroke does not preclude surgery unless it resulted in a total loss of mobility prior to the fall. - Effective surgery identifies the best method to stabilize the hip to allow whatever **functional movement** the patient had remaining to be preserved.

Question 140: A 52-year-old man with a history of intravenous drug use presents to the Emergency Department with a 10-day history of severe lower back pain, fever, and night sweats. He has been unable to work for the past week due to the pain. Temperature is 38.7°C. On examination, there is marked tenderness over the lumbar spine. Blood tests show WBC 14.2 × 10⁹/L, CRP 156 mg/L, and ESR 78 mm/hr. What is the most appropriate next step in the management of this patient?

A. Start empirical broad-spectrum intravenous antibiotics and arrange urgent MRI spine (Correct Answer)
B. Arrange an urgent CT-guided biopsy of the lumbar spine before starting antibiotics
C. Discharge with oral antibiotics and arrange outpatient MRI within 2 weeks
D. Arrange plain radiographs of the lumbar spine to guide further management
E. Perform a lumbar puncture to exclude meningitis before further investigation

Explanation: ***Start empirical broad-spectrum intravenous antibiotics and arrange urgent MRI spine*** - The patient exhibits classic signs of **pyogenic vertebral osteomyelitis/discitis**, including **fever**, **spinal tenderness**, and **intravenous drug use** history, requiring immediate hospitalization and imaging. - **MRI spine** is the gold-standard investigation for diagnosis due to its high sensitivity for detecting **bone marrow edema** and potential **spinal epidural abscesses**. *Arrange an urgent CT-guided biopsy of the lumbar spine before starting antibiotics* - While a **biopsy** is crucial for definitive organism identification, it should not delay initiating **empirical broad-spectrum antibiotics** in a **systemically unwell** patient with high inflammatory markers. - **Blood cultures** should be obtained immediately to attempt pathogen identification, but **empirical antibiotics** take priority when **sepsis** or **neurological compromise** is a risk. *Discharge with oral antibiotics and arrange outpatient MRI within 2 weeks* - Discharge is inappropriate given the **red flag symptoms** of a potential spinal infection and the high risk of permanent **neurological damage** or **sepsis**. - **Oral antibiotics** provide insufficient penetration and coverage compared to **intravenous therapy** required for deep-seated bone infections. *Arrange plain radiographs of the lumbar spine to guide further management* - **Plain radiographs** have very low sensitivity in the early stages of osteomyelitis, as bony changes like **disc space narrowing** may not appear for 2-4 weeks. - A normal X-ray cannot rule out **spinal infection**, making it a poor choice for guiding acute management in a symptomatic patient. *Perform a lumbar puncture to exclude meningitis before further investigation* - The primary clinical finding is **localized spinal tenderness** and back pain, which points toward a **vertebral infection** rather than primary meningitis. - **Lumbar puncture** is not indicated here and could potentially be dangerous if a **spinal epidural abscess** is present at the needle entry site.

Question 141: A 76-year-old man sustains a Garden III intracapsular neck of femur fracture following a fall. He has a past medical history of atrial fibrillation, hypertension, and type 2 diabetes mellitus. His pre-injury mobility was independent with a walking stick outdoors. The orthopaedic team decides to proceed with a cemented hemiarthroplasty. What is the primary reason for using bone cement in this patient's procedure?

A. To reduce the risk of periprosthetic infection by providing antibiotic delivery
B. To improve immediate mechanical stability and allow earlier mobilisation (Correct Answer)
C. To reduce the operative time compared to uncemented fixation techniques
D. To decrease the risk of intraoperative femoral shaft fracture during implantation
E. To provide better long-term osseointegration of the prosthesis

Explanation: ***To improve immediate mechanical stability and allow earlier mobilisation***- **Cemented hemiarthroplasty** provides immediate, rigid fixation, which is crucial for allowing elderly patients with comorbidities to achieve **early weight-bearing** and mobility post-surgery.- Early **mobilisation** is paramount in older hip fracture patients to prevent life-threatening complications such as **pneumonia**, **venous thromboembolism (VTE)**, and pressure sores.*To reduce the risk of periprosthetic infection by providing antibiotic delivery*- While **antibiotic-loaded cement** can offer local antimicrobial protection, this is a secondary benefit rather than the primary mechanical reason for its use.- Intravenous **prophylactic antibiotics** remain the standard primary prevention strategy for surgical site infections, irrespective of cement use.*To reduce the operative time compared to uncemented fixation techniques*- Cementing actually tends to **increase operative time** because the surgeon must wait for the bone cement to cure (harden) before proceeding.- **Uncemented** implants might be faster to insert but carry higher risks of postoperative thigh pain and periprosthetic fractures, especially in osteoporotic bone.*To decrease the risk of intraoperative femoral shaft fracture during implantation*- The use of cement does not necessarily decrease the risk; in fact, the **pressurization of cement** and insertion of the stem can potentially **increase the risk of fracture** in fragile, osteoporotic bone.- Conversely, **uncemented** stems also pose a risk of femoral shaft fracture during the **press-fit** insertion process.*To provide better long-term osseointegration of the prosthesis*- **Osseointegration** is a biological process where bone grows into a porous coating, which is characteristic of **uncemented** implants over several weeks.- **Cemented** implants rely on a **mechanical interlock** between the cement and the cancellous bone for fixation, rather than biological bone ingrowth.

Question 142: A 40-year-old woman presents to her GP with an 8-week history of lower back pain. She works as a cleaner and describes the pain as dull and aching, worse at the end of her working day. She has noticed some early morning stiffness lasting about 10 minutes. She denies any leg pain, bladder or bowel symptoms. On examination, lumbar spine movements are mildly restricted but neurological examination is normal. Which of the following features would be considered a red flag requiring urgent investigation?

A. Age less than 55 years at presentation
B. Morning stiffness lasting less than 30 minutes
C. Pain worse with activity and better with rest
D. Progressive thoracic kyphosis with restriction of chest expansion (Correct Answer)
E. Symptoms duration of 8 weeks

Explanation: ***Progressive thoracic kyphosis with restriction of chest expansion***- A structural deformity or significant loss of spinal mobility suggests serious underlying pathology such as **ankylosing spondylitis** or a **vertebral fracture**, which are red flags.- **Chest expansion restricted** to less than 2.5 cm is a specific clinical sign used to screen for chronic inflammatory spondyloarthropathies.*Age less than 55 years at presentation*- Presentation between the ages of **20 and 55 years** is typically associated with mechanical back pain rather than systemic or neoplastic causes.- A first-time presentation of back pain is only considered a **red flag** if the patient is **younger than 20** or **older than 55** years.*Morning stiffness lasting less than 30 minutes*- Brief morning stiffness is a classic feature of **mechanical back pain** or osteoarthritis rather than inflammatory conditions.- Inflammatory back pain (a red flag category) is characterized by **morning stiffness** lasting **longer than 30-60 minutes** that improves with activity.*Pain worse with activity and better with rest*- This pattern is typical of **mechanical back pain**, which is common in manual workers like cleaners and does not usually require urgent investigation.- Back pain that is **unrelieved by rest**, worse at night, or improves significantly with exercise may indicate **malignancy** or **inflammatory arthritis**.*Symptoms duration of 8 weeks*- A duration of 8 weeks classifies the pain as **subacute**; while persistent, it is not a red flag in the absence of weight loss, night pain, or neurological deficits.- **Chronic duration** without progressive worsening or other "B" symptoms usually points toward benign musculoskeletal etiologies rather than urgent surgical or medical emergencies.

Question 143: A 74-year-old woman presents to the Emergency Department following a fall from standing height. She complains of right hip pain and inability to weight-bear. On examination, the right lower limb is shortened, abducted and externally rotated. Radiographs confirm a displaced intracapsular neck of femur fracture. Which of the following best describes the mechanism by which avascular necrosis occurs following this injury?

A. Damage to the deep circumflex iliac artery leading to ischaemia of the femoral head
B. Disruption of the retinacular vessels which are the primary blood supply to the femoral head (Correct Answer)
C. Compression of the obturator artery within the ligamentum teres causing reduced perfusion
D. Thrombosis of the profunda femoris artery secondary to the trauma
E. Venous congestion causing back-pressure and reduced arterial inflow to the femoral head

Explanation: ***Disruption of the retinacular vessels which are the primary blood supply to the femoral head*** - In **displaced intracapsular neck of femur fractures**, the delicate **retinacular vessels**, which are branches of the medial and lateral circumflex femoral arteries, are often torn or severely compressed. - These vessels are the **primary blood supply** to the **femoral head** in adults, and their disruption directly leads to **avascular necrosis (AVN)**. *Damage to the deep circumflex iliac artery leading to ischaemia of the femoral head* - The **deep circumflex iliac artery** primarily supplies the **iliac crest** and muscles of the abdominal wall, not the femoral head. - Its damage would not directly cause **ischaemia** of the femoral head following an intracapsular hip fracture. *Compression of the obturator artery within the ligamentum teres causing reduced perfusion* - The **artery of the ligamentum teres**, a branch of the **obturator artery**, provides only a **minor and often negligible** blood supply to the femoral head in adults. - It is usually **insufficient** to prevent **avascular necrosis** when the main retinacular supply is compromised. *Thrombosis of the profunda femoris artery secondary to the trauma* - The **profunda femoris artery** (deep femoral artery) is a major artery supplying the **thigh muscles** and gives rise to the circumflex femoral arteries. - A **thrombosis** of the main profunda femoris artery would lead to widespread **lower limb ischaemia**, rather than isolated **femoral head AVN**. *Venous congestion causing back-pressure and reduced arterial inflow to the femoral head* - While increased **intracapsular pressure** can contribute to impaired perfusion, the primary mechanism for **AVN** in **displaced intracapsular fractures** is the direct **mechanical disruption and tearing** of the arterial supply. - **Venous congestion** is not the leading cause for the high incidence of **avascular necrosis** in these types of severe fractures.

Question 144: A 73-year-old woman sustains a subcapital neck of femur fracture with minimal displacement (Garden II). She is an active independent woman who plays golf twice weekly and lives alone. She has well-controlled hypertension and type 2 diabetes. Bone mineral density T-score is -2.8 at the femoral neck. The orthopaedic team discusses fixation versus arthroplasty options. Which factor most strongly supports proceeding with internal fixation with cannulated screws rather than arthroplasty?

A. The patient's good pre-injury functional status and activity level
B. The undisplaced nature of the fracture reduces avascular necrosis risk (Correct Answer)
C. Her age of 73 years is below the threshold for primary arthroplasty
D. Presence of osteoporosis improves screw purchase in cancellous bone
E. Type 2 diabetes reduces prosthetic joint infection risk

Explanation: ***The undisplaced nature of the fracture reduces avascular necrosis risk***- In **Garden I and II** (undisplaced) fractures, the **retinacular blood supply** to the femoral head is largely preserved, making **internal fixation** a viable option with lower risk of failure.- Preserving the native anatomy through fixation is generally preferred for **undisplaced fractures** regardless of age, as the risks of **avascular necrosis (AVN)** and **non-union** are significantly lower than in displaced fractures.*The patient's good pre-injury functional status and activity level*- High activity levels often favor **arthroplasty** (especially **Total Hip Replacement**) in active elderly patients, as it allows for immediate weight-bearing and avoids the risk of **fixation failure** or reoperation.- While good functional status is crucial for surgical eligibility, it doesn't provide a biological rationale for choosing **internal fixation** over **arthroplasty**; rather, it often argues for arthroplasty for quicker rehabilitation.*Her age of 73 years is below the threshold for primary arthroplasty*- There is no strict **age threshold** for arthroplasty; in fact, **primary arthroplasty** (hemi or total) is generally recommended for most elderly patients (e.g., >65 years) with **displaced** neck of femur fractures.- The decision for arthroplasty versus fixation is primarily based on the **fracture displacement** (Garden classification) and the patient's physiological age and comorbidities, not a chronological age cutoff.*Presence of osteoporosis improves screw purchase in cancellous bone*- **Osteoporosis** (T-score -2.8) signifies **reduced bone density** and weakens bone quality, which directly **impairs screw purchase** and increases the risk of **hardware cutout** or implant failure.- Poor bone mineral density is a relative **contraindication** to internal fixation, as the osteoporotic bone may not provide sufficient **stability** for the implants, leading to higher rates of non-union or reoperation.*Type 2 diabetes reduces prosthetic joint infection risk*- **Type 2 diabetes mellitus** is a well-established independent **risk factor** that significantly **increases** the risk of **prosthetic joint infection (PJI)** and impairs wound healing.- Uncontrolled or even well-controlled diabetes introduces systemic challenges that make any surgical intervention, especially arthroplasty, potentially more complicated, making this statement incorrect.

Question 145: A 67-year-old woman presents to the Emergency Department with acute onset severe lower back pain and bilateral leg weakness that developed over 6 hours. She has metastatic lung cancer currently receiving palliative chemotherapy. On examination, power is 2/5 bilaterally in all muscle groups of both legs, with a sensory level at T10, absent ankle reflexes, and reduced perianal sensation. MRI demonstrates cord compression at T9-T10 with significant canal compromise. Despite immediate high-dose dexamethasone, her neurology deteriorates to complete paraplegia over the next 4 hours. What is the most appropriate definitive management at this stage?

A. Emergency surgical decompression and stabilisation within 6 hours of presentation
B. Emergency radiotherapy to the affected spinal segment within 24 hours (Correct Answer)
C. Continue high-dose corticosteroids and reassess neurology in 48 hours
D. Palliative care approach with analgesia and supportive measures only
E. Intrathecal chemotherapy via lumbar puncture

Explanation: ***Emergency radiotherapy to the affected spinal segment within 24 hours*** - In cases of **Metastatic Spinal Cord Compression (MSCC)** with rapid progression to **complete paraplegia**, especially in patients with advanced systemic disease (e.g., metastatic lung cancer on palliative chemotherapy), **radiotherapy** is the most appropriate definitive management. - While full functional recovery is unlikely after complete paralysis, urgent radiotherapy helps to **control local tumor growth**, provide **pain relief**, and prevent the sensory level from ascending, thereby improving quality of life. *Emergency surgical decompression and stabilisation within 6 hours of presentation* - Surgical decompression is generally favored for **ambulatory patients**, those with rapidly progressive neurological deficits who are **neurologically intact or only partially compromised**, and those with good performance status and longer life expectancy. - For a patient with **complete paraplegia** and advanced metastatic disease, the significant risks and invasiveness of major spinal surgery often outweigh the very low likelihood of functional recovery, making it less appropriate than radiotherapy. *Continue high-dose corticosteroids and reassess neurology in 48 hours* - **High-dose dexamethasone** is a crucial initial measure to reduce **peritumoral edema** and provide temporary relief in MSCC, but it is an **adjunctive treatment** and not a definitive therapy for mechanical cord compression. - Waiting 48 hours for reassessment without providing a definitive local treatment (such as radiotherapy or surgery) risks further **irreversible spinal cord damage** due to ongoing compression and ischemia. *Palliative care approach with analgesia and supportive measures only* - While the patient is receiving palliative chemotherapy, **MSCC is an oncological emergency** that still warrants active intervention to manage symptoms and prevent further complications, even if functional recovery is limited. - A purely supportive approach may lead to **ascension of the sensory level**, potentially causing autonomic dysfunction, respiratory compromise, and increased suffering that could be mitigated by targeted treatment like radiotherapy. *Intrathecal chemotherapy via lumbar puncture* - **Intrathecal chemotherapy** is primarily indicated for **leptomeningeal carcinomatosis**, which involves cancer cells spreading within the cerebrospinal fluid and meninges. - This patient has **extradural cord compression** from a solid tumor mass, not leptomeningeal disease, and a lumbar puncture is generally **contraindicated** in the presence of an obstructive spinal mass due to the risk of neurological deterioration or spinal herniation.

Question 146: A 55-year-old man presents with a 6-month history of lower back pain and progressive bilateral leg weakness. He reports a 12 kg weight loss and has noticed his urine has become very dark. Blood tests show: Hb 96 g/L, corrected calcium 3.2 mmol/L, creatinine 145 μmol/L, ESR 85 mm/hr, and total protein 95 g/L. Serum protein electrophoresis shows a monoclonal band. Lumbar spine radiographs demonstrate multiple lytic lesions. What is the most likely diagnosis?

A. Metastatic prostate carcinoma with bony metastases
B. Multiple myeloma with vertebral involvement (Correct Answer)
C. Primary hyperparathyroidism with brown tumours
D. Spinal tuberculosis with vertebral destruction
E. Waldenstrom's macroglobulinaemia with bone involvement

Explanation: ***Multiple myeloma with vertebral involvement***- The constellation of **hypercalcaemia**, **renal impairment**, **anaemia**, and **lytic bone lesions** (the **CRAB criteria**), combined with a **monoclonal band** on serum protein electrophoresis and markedly elevated **ESR**, is highly diagnostic of **Multiple Myeloma**.- The progressive **bilateral leg weakness** and **lower back pain** are consistent with vertebral involvement and potential spinal cord compression or nerve root impingement from the lytic lesions.*Metastatic prostate carcinoma with bony metastases*- **Prostate carcinoma** bony metastases are typically **osteoblastic (sclerotic)** on imaging, in contrast to the **lytic lesions** seen in this patient.- This diagnosis would not explain the presence of a **monoclonal band** on serum protein electrophoresis or the significantly elevated total protein.*Primary hyperparathyroidism with brown tumours*- While **primary hyperparathyroidism** causes **hypercalcaemia** and can lead to bone lesions (brown tumors), it does not explain the pronounced **anaemia**, significantly elevated **ESR**, or the crucial finding of a **monoclonal band**.- Brown tumors are typically associated with very high **parathyroid hormone (PTH)** levels and are distinct from widespread lytic lesions.*Spinal tuberculosis with vertebral destruction*- **Spinal tuberculosis** (Pott's disease) involves **vertebral destruction** but usually presents with **disc space narrowing**, kyphosis, and abscess formation, which differs from the described **multiple lytic lesions**.- This condition does not account for the **monoclonal gammopathy**, significant **hypercalcaemia**, or the pattern of systemic features observed.*Waldenstrom's macroglobulinaemia with bone involvement*- **Waldenstrom's macroglobulinaemia** is characterized by an **IgM monoclonal gammopathy** and can cause anaemia and elevated ESR, but it **rarely causes lytic bone lesions** or significant **hypercalcaemia**.- Clinical features typically include **hyperviscosity syndrome**, lymphadenopathy, and hepatosplenomegaly, which are not described here.

Question 147: A 72-year-old woman sustains a reverse oblique intertrochanteric femur fracture. Pre-injury she was independently mobile with one stick. The fracture line extends from proximolateral to distomedial and is highly unstable. Which fixation method provides the most biomechanically stable construct for this fracture pattern?

A. Sliding hip screw with derotation screw
B. Multiple cannulated screws in parallel configuration
C. Cephalomedullary nail with proximal and distal locking screws (Correct Answer)
D. Cemented hemiarthroplasty with long stem
E. External fixation with pins in iliac crest and proximal femur

Explanation: ***Cephalomedullary nail with proximal and distal locking screws*** - A **reverse oblique intertrochanteric fracture** is highly unstable because the fracture line parallels the pull of the **adductor muscles**, leading to medialization of the distal fragment. - The intramedullary position of a **cephalomedullary nail** provides a shorter **lever arm** and acts as a load-sharing device, effectively preventing the **medial displacement** and varus collapse common in this pattern. *Sliding hip screw with derotation screw* - In reverse oblique patterns, the **sliding hip screw (SHS)** is contraindicated because the fracture line is parallel to the screw, which can lead to catastrophic **medialization of the shaft** and hardware failure. - The SHS relies on a lateral cortex for a **buttress**, which is absent or compromised in this specific fracture configuration. *Multiple cannulated screws in parallel configuration* - This fixation method lacks the required **biostatic strength** and structural stability to support the heavy loads of an **extracapsular fracture**. - Parallel screws are primarily indicated for **nondisplaced intracapsular femoral neck fractures**, not unstable intertrochanteric patterns. *Cemented hemiarthroplasty with long stem* - While used for severely comminuted fractures in the very elderly, **internal fixation** is preferred for extracapsular fractures to preserve the native joint in a patient who was **independently mobile**. - Hemiarthroplasty is generally reserved for **intracapsular fractures** or as a salvage procedure after failed fixation, rather than primary treatment for this pattern. *External fixation with pins in iliac crest and proximal femur* - External fixation is rarely used for definitive femur fracture management and is typically reserved for **damage control orthopaedics** in polytrauma patients. - It provides poor **biomechanical stability** for weight-bearing and carries a high risk of **pin-site infection** and non-union in this age group.

Question 148: A 65-year-old woman with metastatic breast cancer presents with a 6-week history of progressively worsening thoracic back pain that is constant, unrelieved by rest, and worse at night. Over the past 48 hours, she has developed bilateral leg weakness and difficulty walking. On examination, power is 3/5 in both legs with a sensory level at T8 and brisk reflexes with upgoing plantars. Perianal sensation is intact. What is the most appropriate immediate management?

A. Commence oral dexamethasone 16mg daily and arrange routine MRI spine within 1 week
B. Give intravenous dexamethasone 16mg immediately and arrange urgent MRI whole spine within 24 hours (Correct Answer)
C. Arrange urgent CT spine and commence chemotherapy for metastatic disease
D. Refer to oncology for urgent radiotherapy planning without imaging
E. Commence analgesia and arrange palliative care assessment

Explanation: ***Give intravenous dexamethasone 16mg immediately and arrange urgent MRI whole spine within 24 hours***- This patient presents with signs of **metastatic spinal cord compression (MSCC)**, an oncological emergency requiring immediate **high-dose corticosteroids** to reduce peritumoral edema and preserve neurological function.- An **urgent MRI of the whole spine** within 24 hours is essential to confirm the level of compression, rule out multi-level disease, and guide definitive surgical or radiation therapy.*Commence oral dexamethasone 16mg daily and arrange routine MRI spine within 1 week*- Delaying the **MRI spine** for up to a week is inappropriate for suspected MSCC, as irreversible **neurological deficits** like paralysis can develop rapidly.- While oral dexamethasone is an option, the term "**routine**" MRI fails to address the critical urgency required for imaging in a patient with acute neurological compromise.*Arrange urgent CT spine and commence chemotherapy for metastatic disease*- **MRI** is the superior imaging modality for evaluating the **spinal cord** and soft tissue lesions causing compression, whereas **CT spine** has limited ability to visualize the cord directly.- **Chemotherapy** is generally not the immediate treatment for acute cord compression; prompt mechanical decompression (surgery) or radiotherapy is needed to relieve pressure on the cord.*Refer to oncology for urgent radiotherapy planning without imaging*- Performing **radiotherapy** without prior **MRI imaging** is inappropriate and potentially harmful, as it prevents precise localization of the compression and assessment for surgical candidacy.- **Imaging** is crucial to determine the extent of disease, stability of the spine, and to differentiate between cases that require **surgical decompression** versus those best managed by radiotherapy alone.*Commence analgesia and arrange palliative care assessment*- While **pain management** is important, this approach overlooks the **neurological emergency** of MSCC, which requires immediate, aggressive intervention to preserve function.- A patient with **metastatic breast cancer** experiencing acute spinal cord compression has a potentially reversible cause of neurological decline, making palliative care alone premature.

Question 149: A 69-year-old man undergoes a cemented hemiarthroplasty for a displaced subcapital neck of femur fracture. During cement insertion, he suddenly develops severe hypotension (BP 75/40 mmHg), hypoxia (SpO2 82%), and decreased consciousness. The anaesthetist notes a significant rise in end-tidal CO2 and ECG shows changes consistent with right heart strain. What is the primary pathophysiological mechanism underlying this acute deterioration?

A. Anaphylactic reaction to methylmethacrylate cement causing vasodilation
B. Cement and marrow embolisation causing pulmonary vascular occlusion and right ventricular failure (Correct Answer)
C. Acute myocardial infarction secondary to increased sympathetic stimulation
D. Haemorrhagic shock from unrecognised femoral artery injury
E. Air embolism from entrainment during femoral canal preparation

Explanation: ***Cement and marrow embolisation causing pulmonary vascular occlusion and right ventricular failure*** - This patient's symptoms are characteristic of **Bone Cement Implantation Syndrome (BCIS)**, where high intramedullary pressure forces **fat, marrow debris, and air** into the venous circulation during cementation. - These emboli lead to a sudden increase in **pulmonary vascular resistance**, causing **acute right heart strain** (seen on ECG), severe hypoxia, and systemic hypotension due to reduced cardiac output. *Anaphylactic reaction to methylmethacrylate cement causing vasodilation* - While methylmethacrylate (MMA) can cause a transient drop in blood pressure, a full **anaphylactic reaction** is rare and typically involves widespread **vasodilation**, rash, or bronchospasm, which are not mentioned. - This mechanism would not explain the prominent **right heart strain** and **pulmonary vascular occlusion** observed in the patient. *Acute myocardial infarction secondary to increased sympathetic stimulation* - Although surgical stress can precipitate an MI, the immediate onset of **hypoxia, hypotension, and right heart strain** specifically during cement insertion is pathognomonic for **BCIS**, not typically MI. - An MI would usually present with different **ECG changes** (e.g., ST elevation) and would not directly cause the observed **pulmonary hypertension** signs. *Haemorrhagic shock from unrecognised femoral artery injury* - **Haemorrhagic shock** would cause hypotension and possibly decreased consciousness, but it would not typically lead to the acute **hypoxia** or the distinct **right heart strain** seen here. - Such an injury would likely manifest with significant blood loss and a falling hemoglobin, which are not the primary features of this acute deterioration. *Air embolism from entrainment during femoral canal preparation* - **Air embolism** can contribute to the embolic load in BCIS, but the primary pathophysiological mechanism involves a broader mixture of **cement monomers, fat, and marrow debris** creating mechanical and biochemical effects. - While femoral canal preparation can cause air entrainment, the most severe symptoms of BCIS are classically linked to the **cement pressurization** phase.

Question 150: A 58-year-old woman presents to her GP with a 4-month history of lower back pain, night sweats, and unintentional weight loss of 8 kg. She emigrated from South Asia 15 years ago. On examination, there is tenderness over the lower thoracic spine and a palpable fluctuant mass in the right groin. ESR is 95 mm/hr and chest radiograph shows apical shadowing. What is the most appropriate next investigation to confirm the diagnosis?

A. Whole-body bone scan with technetium-99m
B. MRI spine with contrast (Correct Answer)
C. CT-guided biopsy of vertebral body with microbiological culture
D. Serum protein electrophoresis and Bence Jones protein
E. Fine needle aspiration of the groin mass

Explanation: ***MRI spine with contrast*** - **MRI** is the gold standard imaging modality for diagnosing **spinal tuberculosis (Pott's disease)** as it identifies vertebral destruction, **disc space narrowing**, and the extent of soft tissue involvement. - It is essential to visualize the **psoas abscess** tracking to the groin and to assess for any **spinal cord compression** that may necessitate urgent surgical intervention. *Whole-body bone scan with technetium-99m* - This investigation is sensitive for increased bone turnover, such as **metastatic disease**, but lacks the specificity required to diagnose **spinal TB**. - It cannot provide detailed information regarding **soft tissue collections** or paraspinal involvement, which are hallmark features of this presentation. *CT-guided biopsy of vertebral body with microbiological culture* - While this provides the definitive **microbiological gold standard** diagnosis, imaging must be performed first to guide the biopsy site and map the disease extent. - Obtaining tissue is critical for **drug sensitivity testing**, but it should follow the diagnostic confirmation and anatomical mapping provided by **MRI**. *Serum protein electrophoresis and Bence Jones protein* - These tests are used to screen for **Multiple Myeloma**, which can cause back pain and weight loss, but do not explain the **groin mass** or **apical shadowing**. - The clinical context of being an immigrant from a TB-endemic region and having **night sweats** makes an infectious etiology much more likely than a plasma cell dyscrasia. *Fine needle aspiration of the groin mass* - Although aspiration of the **psoas abscess** (cold abscess) may yield pus for **AFB staining** and culture, it does not allow for assessment of the spinal stability. - Relying solely on a groin sample would miss critical information regarding the **neurological risk** and vertebral destruction at the thoracic level.

Question 151: An 83-year-old woman presents with a subcapital neck of femur fracture following a fall. She has advanced Alzheimer's dementia (Abbreviated Mental Test Score 2/10), is doubly incontinent, and was bed-bound prior to the injury. She lives in a nursing home and requires total care for all activities of daily living. Her medical history includes ischaemic heart disease, chronic kidney disease stage 4, and previous stroke with residual hemiparesis. What is the most appropriate initial management approach?

A. Cemented total hip replacement to allow immediate weight-bearing
B. Uncemented hemiarthroplasty with post-operative protected weight-bearing
C. Non-operative management with analgesia and early mobilisation as tolerated (Correct Answer)
D. Dynamic hip screw fixation with bone grafting
E. Cannulated screw fixation under regional anaesthesia

Explanation: ***Non-operative management with analgesia and early mobilisation as tolerated***- In patients who were **bed-bound before the injury** with **advanced dementia** (AMTS 2/10) and multiple **high-risk comorbidities** (IHD, CKD stage 4, stroke), surgery offers no functional benefit and carries significant risks.- The primary focus shifts to **palliative care**, ensuring **effective pain relief** and comfortable positioning, rather than attempting to restore ambulation. *Cemented total hip replacement to allow immediate weight-bearing*- This major procedure is typically reserved for **ambulatory patients** with a reasonable life expectancy who can benefit from restoration of function.- It is unsuitable for a bed-bound patient with **severe cognitive impairment** and significant **cardiac and renal comorbidities**, as the risks outweigh any potential benefit. *Uncemented hemiarthroplasty with post-operative protected weight-bearing*- While hemiarthroplasty is common for displaced neck of femur fractures in the elderly, **uncemented implants** are generally avoided in this population due to a higher risk of **periprosthetic fractures**.- The patient's **pre-existing bed-bound status** means protected weight-bearing is irrelevant, and the high surgical risks remain a contraindication. *Dynamic hip screw fixation with bone grafting*- **Dynamic hip screws (DHS)** are specifically designed for **extracapsular fractures**, such as intertrochanteric fractures, not the **intracapsular subcapital fracture** described.- **Bone grafting** is an unnecessary and invasive addition, especially in a frail, elderly patient with **poor baseline function** and multiple health issues. *Cannulated screw fixation under regional anaesthesia*- **Cannulated screw fixation** is primarily indicated for **undisplaced femoral neck fractures** or in younger, more active patients to preserve the femoral head.- For a **displaced subcapital fracture** in an 83-year-old, there's a high risk of **avascular necrosis** and non-union, and the procedure would not improve her functional status.

Question 152: A 46-year-old man presents to the Emergency Department with a 36-hour history of severe lower back pain and urinary retention. He reports numbness in the perineal area and difficulty initiating urination for the past 8 hours. On examination, there is reduced anal tone on digital rectal examination and sensory loss in the S2-S4 dermatomes. Bilateral leg strength is 4/5 with absent ankle reflexes. What is the most appropriate immediate management?

A. Urgent MRI lumbar spine and refer to neurosurgery for emergency decompression (Correct Answer)
B. Insert urinary catheter, commence high-dose oral corticosteroids, and arrange outpatient MRI
C. Arrange CT lumbar spine, commence analgesia, and refer to physiotherapy
D. Commence intravenous antibiotics and arrange CT-guided biopsy of lumbar spine
E. Prescribe bed rest, NSAIDs, and arrange follow-up with GP in 48 hours

Explanation: ***Urgent MRI lumbar spine and refer to neurosurgery for emergency decompression*** - The clinical presentation of **saddle anesthesia**, **urinary retention**, and **reduced anal tone** is pathognomonic for **Cauda Equina Syndrome (CES)**, a neurosurgical emergency. - **Urgent MRI** is the gold standard for diagnosis, and **surgical decompression** must be performed within 24-48 hours to prevent permanent neurological damage. *Insert urinary catheter, commence high-dose oral corticosteroids, and arrange outpatient MRI* - While a catheter manages the urinary retention, delaying imaging with an **outpatient MRI** is incorrect as it risks permanent **sphincter and sexual dysfunction**. - High-dose **corticosteroids** are used for spinal cord compression due to malignancy or inflammation, but are not the primary treatment for mechanical **CES** due to disc herniation. *Arrange CT lumbar spine, commence analgesia, and refer to physiotherapy* - **CT scans** are less sensitive than **MRI** for visualizing soft tissue structures and nerve root compression in the lumbar spine. - **Physiotherapy** is contraindicated in the acute phase of **Cauda Equina Syndrome** as it does nothing to alleviate the mechanical compression. *Commence intravenous antibiotics and arrange CT-guided biopsy of lumbar spine* - This management is for **discitis** or **vertebral osteomyelitis**, which usually presents with fever and localized tenderness rather than acute bladder dysfunction. - Initiating **antibiotics** and a **biopsy** without emergency imaging delays the essential decompression needed for the suspected nerve root compression. *Prescribe bed rest, NSAIDs, and arrange follow-up with GP in 48 hours* - This conservative approach is for **mechanical lower back pain**, but it is dangerously inappropriate for a patient showing **red flag symptoms**. - Delaying specialized assessment by 48 hours in a patient with **urinary retention** and loss of reflexes often leads to **irreversible paraplegia** or bowel/bladder incontinence.

Question 153: A 70-year-old man sustains a displaced intracapsular neck of femur fracture. He has a past medical history of chronic obstructive pulmonary disease, type 2 diabetes mellitus, and previous myocardial infarction 8 months ago with a drug-eluting stent insertion. He is on dual antiplatelet therapy with aspirin and clopidogrel. The orthopaedic team plans a cemented hemiarthroplasty. What is the most appropriate peri-operative management of his antiplatelet therapy?

A. Continue both aspirin and clopidogrel throughout the peri-operative period
B. Stop both aspirin and clopidogrel 7 days before surgery and restart 24 hours post-operatively
C. Continue aspirin and stop clopidogrel 7 days before surgery (Correct Answer)
D. Stop clopidogrel 5 days before surgery and continue aspirin throughout
E. Stop both agents and bridge with intravenous heparin peri-operatively

Explanation: ***Continue aspirin and stop clopidogrel 7 days before surgery*** - For a patient with a **drug-eluting stent** placed within the last year (8 months ago), **aspirin** should be continued peri-operatively to mitigate the high risk of **stent thrombosis** and **acute coronary events**. - **Clopidogrel** is an irreversible P2Y12 inhibitor that significantly increases **peri-operative bleeding** risk during major surgery; it should ideally be stopped **7 days** prior to allow for new platelet turnover. *Continue both aspirin and clopidogrel throughout the peri-operative period* - Continuing **dual antiplatelet therapy (DAPT)** during a cemented hemiarthroplasty carries an unacceptably high risk of **uncontrolled surgical hemorrhage** and potential need for transfusions. - While DAPT is critical for preventing stent-related events, the acute surgical risk outweighs the benefit of continuing clopidogrel in this context. *Stop both aspirin and clopidogrel 7 days before surgery and restart 24 hours post-operatively* - Completely stopping both agents creates a dangerously high-risk window for **acute myocardial infarction** or **stent thrombosis**, especially given the recent **drug-eluting stent**. - **Aspirin monotherapy** is considered the standard baseline protection that should not be interrupted for this type of orthopedic surgery in patients with cardiovascular risk. *Stop clopidogrel 5 days before surgery and continue aspirin throughout* - While some newer guidelines may consider a **5-day** hold for clopidogrel in certain situations, a **7-day** window is the more traditionally accepted and safer period to ensure maximal platelet recovery for major orthopedic surgery. - The longer washout period of 7 days offers a greater margin of safety against **significant surgical bleeding** for an irreversible antiplatelet agent like clopidogrel. *Stop both agents and bridge with intravenous heparin peri-operatively* - **Heparin bridging** is typically employed for patients on **oral anticoagulants** (e.g., warfarin) who require temporary interruption, not for **antiplatelet agents**. - Heparin's mechanism of action (anticoagulation) does not provide the specific **antiplatelet protection** needed to prevent **stent thrombosis**, which is addressed by aspirin.

Question 154: A 52-year-old woman presents with a 3-month history of lower back pain radiating to both buttocks and posterior thighs. She reports that the pain is worse when walking uphill or standing and is relieved when sitting or leaning forward on a shopping trolley. Neurological examination reveals normal power, sensation, and reflexes in both lower limbs. What is the most likely underlying pathological mechanism?

A. Lumbar disc prolapse causing nerve root compression
B. Narrowing of the spinal canal causing neurogenic claudication (Correct Answer)
C. Spondylolisthesis causing mechanical instability
D. Facet joint osteoarthritis causing referred pain
E. Sacroiliac joint inflammation causing bilateral radiculopathy

Explanation: ***Narrowing of the spinal canal causing neurogenic claudication*** - The patient exhibits the classic **'shopping trolley sign'**, where leaning forward (spinal flexion) increases the **spinal canal diameter**, providing symptom relief. - **Neurogenic claudication** typically presents with bilateral leg pain triggered by walking or standing (spinal extension), which further narrows the already stenotic lumbar canal. *Lumbar disc prolapse causing nerve root compression* - Usually presents as **acute unilateral radiculopathy** (sciatica) rather than bilateral symptoms triggered by specific postures like standing. - Often associated with positive **straight leg raise** tests and specific focal **neurological deficits**, which are absent in this case. *Spondylolisthesis causing mechanical instability* - While it can lead to stenosis, primary mechanical instability typically causes **localized back pain** that worsens with specific movements or lifting transitions. - It often presents with a palpable **'step-off'** deformity on examination and does not always follow the classic flexion-relief pattern of central stenosis. *Facet joint osteoarthritis causing referred pain* - Typically causes **localized stiffness** and pain that is worse with **spinal extension** and rotation, but it does not usually cause radiating claudication symptoms. - Referred pain from facet joints generally does not follow a **dermatomal distribution** to the posterior thighs and lacks the 'shopping trolley' relief pattern. *Sacroiliac joint inflammation causing bilateral radiculopathy* - **Sacroiliitis** generally causes pain over the **buttocks and groin** that is worse with sitting and improved by walking, which is the opposite of this patient's presentation. - Inflammation of these joints does not cause true **radiculopathy** or neurogenic claudication symptoms localized to the spinal canal.

Question 155: A 77-year-old woman undergoes cannulated screw fixation for an undisplaced Garden II subcapital neck of femur fracture. Post-operatively, she develops sudden onset severe right-sided chest pain, dyspnoea, and hypotension 18 hours after surgery. She becomes acutely confused and her oxygen saturations drop to 84% on room air. An ECG shows sinus tachycardia and right bundle branch block. What is the most likely diagnosis?

A. Fat embolism syndrome (Correct Answer)
B. Acute myocardial infarction
C. Bone cement implantation syndrome
D. Pulmonary embolism
E. Hospital-acquired pneumonia

Explanation: ***Fat embolism syndrome*** - Occurs classically 24-72 hours post-orthopaedic surgery involving **long bone fractures**, presenting with a **triad** of **respiratory distress**, **neurological dysfunction** (confusion), and sometimes a **petechial rash**.- The sudden onset of severe **dyspnoea**, **hypotension**, **hypoxia** (84% O2 sats), and **acute confusion** 18 hours after femur fracture fixation is highly characteristic of fat embolism. *Acute myocardial infarction*- While it can cause chest pain and hypotension, an ECG would typically show **ST-segment changes** or T-wave inversions rather than a new **Right Bundle Branch Block** as the primary cardiac finding.- **Acute confusion** is a less prominent or primary symptom in AMI compared to the respiratory and neurological features seen here, especially in the context of recent orthopaedic trauma.*Bone cement implantation syndrome*- Characterized by hypoxia and hypotension occurring **intra-operatively**, specifically during the **pressurisation of cement** or prosthesis insertion.- This patient underwent **cannulated screw fixation** for an undisplaced fracture, a procedure that does **not involve bone cement**, making this diagnosis impossible.*Pulmonary embolism*- Typically presents with sudden onset **dyspnoea**, **chest pain**, and **hypotension** (as seen here), and can cause RBBB due to right heart strain.- However, the significant and sudden **neurological deterioration** (acute confusion) in combination with respiratory symptoms and timing post-long bone fracture is more indicative of **fat embolism syndrome**.*Hospital-acquired pneumonia*- Usually presents with **fever**, productive cough, and **basal crackles** rather than sudden onset severe chest pain and hypotension.- Development within **18 hours** is too rapid for typical HAP, which usually requires at least 48 hours of hospitalisation to manifest.

Question 156: A 68-year-old man presents to his GP with a 5-month history of progressively worsening lower back pain. He describes difficulty fastening his shoes due to back stiffness, particularly in the mornings. On examination, there is reduced lumbar spine flexion with a positive Schober's test (less than 5cm expansion). What is the most appropriate initial investigation to establish the diagnosis?

A. Lumbar spine MRI
B. Anteroposterior pelvis radiograph (Correct Answer)
C. HLA-B27 antigen testing
D. Erythrocyte sedimentation rate and C-reactive protein
E. Bone mineral density DEXA scan

Explanation: ***Anteroposterior pelvis radiograph***- The patient's clinical presentation of **worsening lower back pain**, **morning stiffness**, reduced lumbar flexion, and a **positive Schober's test** strongly suggests **Ankylosing Spondylitis**, necessitating investigation of the sacroiliac joints.- An anteroposterior pelvis radiograph is the most appropriate **initial imaging investigation** to detect **sacroiliitis**, which manifests as erosions, sclerosis, or joint space narrowing. *Lumbar spine MRI*- While MRI is highly sensitive for detecting **early inflammatory changes** like bone marrow edema in sacroiliac joints, it is often reserved for cases where plain radiographs are inconclusive or for assessing disease activity.- MRI is not typically the **first-line investigation** to establish a diagnosis of Ankylosing Spondylitis when clinical signs are clear and conventional radiography is available.*HLA-B27 antigen testing*- Although approximately 90% of patients with Ankylosing Spondylitis are **HLA-B27 positive**, this genetic marker is not diagnostic on its own as it can be found in a significant portion of the healthy population.- It serves as a **supportive factor** rather than the initial diagnostic test to confirm clinical sacroiliitis.*Erythrocyte sedimentation rate and C-reactive protein*- **ESR and CRP** are non-specific inflammatory markers that can be elevated in active Ankylosing Spondylitis, but they are normal in up to 50% of patients.- These tests are more useful for monitoring disease activity or ruling out other inflammatory conditions, not for the **initial definitive diagnosis**.*Bone mineral density DEXA scan*- A DEXA scan is used to assess **bone mineral density** and diagnose conditions like **osteoporosis**, which can be a complication of chronic Ankylosing Spondylitis due to chronic inflammation and reduced mobility.- It has no role in the **initial diagnosis** of the inflammatory condition itself, which primarily involves the sacroiliac joints and spine.

Question 157: A 74-year-old woman presents to the Emergency Department following a mechanical fall. Radiographs demonstrate a subcapital neck of femur fracture with complete displacement and rotation of the femoral head. The fracture fragments are not aligned and there is no bony contact between them. According to the Garden classification system, what grade is this fracture?

A. Garden I - incomplete fracture with impaction in valgus position
B. Garden II - complete fracture without displacement
C. Garden III - complete fracture with partial displacement
D. Garden IV - complete fracture with complete displacement (Correct Answer)
E. Garden V - comminuted fracture with segmental fragments

Explanation: ***Garden IV - complete fracture with complete displacement*** - This grade is characterized by a **complete fracture** with **total displacement** and often **rotation** of the femoral head, leading to a complete loss of bony contact between fragments. - Radiographically, the **trabeculae** of the femoral head are no longer aligned with those of the acetabulum, indicating a high risk of **avascular necrosis**. *Garden I - incomplete fracture with impaction in valgus position* - Represents an **incomplete** or **impacted** fracture where the trabeculae are angulated in a **valgus** position. - These are considered **undisplaced fractures** with a better prognosis and lower risk of blood supply disruption. *Garden II - complete fracture without displacement* - This is a **complete fracture** across the femoral neck, but the fragments remain in their **anatomical position**. - The **trabecular lines** across the fracture site remain **aligned** and uninterrupted on radiographs. *Garden III - complete fracture with partial displacement* - Describes a complete fracture with **partial displacement** where some degree of **bony contact** still exists between the two fragments. - The femoral head usually tilts into a **varus position**, causing the trabeculae to become **misaligned**. *Garden V - comminuted fracture with segmental fragments* - The Garden classification system only includes **four grades**, ranging from incomplete to completely displaced fractures. - There is **no Garden V** in the standard classification for intracapsular neck of femur fractures.

Question 158: A 75-year-old woman undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cement insertion, she develops sudden hypotension (BP 70/40 mmHg), hypoxia (SpO2 85%), and loss of consciousness. What is the most likely diagnosis?

A. Anaphylactic reaction to cement components
B. Bone cement implantation syndrome (Correct Answer)
C. Pulmonary embolism from pre-existing deep vein thrombosis
D. Intraoperative myocardial infarction
E. Fat embolism syndrome

Explanation: ***Bone cement implantation syndrome*** - This clinical triad of **hypotension**, **hypoxia**, and **loss of consciousness** occurring specifically during **cement insertion** or prosthesis pressurization is classic for **Bone Cement Implantation Syndrome (BCIS)**. - It is caused by the **embolization of bone marrow contents**, air, and other debris into the pulmonary circulation due to **increased intramedullary pressure**, leading to acute cardiorespiratory collapse. *Anaphylactic reaction to cement components* - While exposure to **methyl methacrylate** can cause adverse reactions, true **IgE-mediated anaphylaxis** to bone cement components is exceedingly rare in the intraoperative setting. - The sudden, immediate onset during cement pressurization is far more characteristic of the mechanical and embolic pathophysiology of BCIS rather than an allergic reaction. *Pulmonary embolism from pre-existing deep vein thrombosis* - A **pulmonary embolism (PE)** from a pre-existing DVT can cause sudden hypoxia and hypotension; however, its occurrence is less precisely timed with the **cement insertion** phase compared to BCIS. - PE due to DVT typically has a more variable timeline and might not manifest as instantly and severely concurrent with the **mechanical process** of cementing. *Intraoperative myocardial infarction* - An **intraoperative myocardial infarction (MI)** can lead to hypotension and altered consciousness, but the initial presentation would likely involve **ECG changes**, severe arrhythmias, or signs of cardiac ischemia, with hypoxia often being a secondary effect. - The acute, concurrent onset of severe hypotension, hypoxia, and loss of consciousness directly linked to **cement pressurization** is less typical for a primary MI and more indicative of an embolic event. *Fat embolism syndrome* - **Fat embolism syndrome (FES)** usually has a **delayed onset**, typically appearing 24 to 72 hours post-injury or surgery, not immediately during the procedure. - FES is classically characterized by a triad of **respiratory distress**, **neurological dysfunction**, and **petechial rash**, which is distinct from the immediate cardiovascular collapse observed with BCIS.

Question 159: A 56-year-old man presents with a 3-month history of lower back pain and progressive bilateral leg weakness. Examination reveals brisk knee reflexes, upgoing plantar responses bilaterally, and sensory level at T10. MRI shows cord compression at T8 level. What is the most likely diagnosis?

A. Lumbar spinal stenosis with cauda equina compression
B. Thoracic disc herniation with spinal cord compression (Correct Answer)
C. Peripheral neuropathy with concurrent lumbar radiculopathy
D. Multiple sclerosis with transverse myelitis
E. Motor neuron disease with upper and lower motor neuron signs

Explanation: ***Thoracic disc herniation with spinal cord compression*** - The presence of **upper motor neuron (UMN) signs**, such as **brisk knee reflexes** and **upgoing plantar responses**, directly points to spinal cord involvement. - A **sensory level at T10** combined with MRI findings of **cord compression at T8 level** definitively localizes the lesion to the thoracic spinal cord, which is consistent with thoracic disc herniation. *Lumbar spinal stenosis with cauda equina compression* - **Cauda equina compression** affects **lower motor neurons (LMNs)**, presenting with **flaccid weakness**, **diminished or absent reflexes**, and **downgoing plantar responses**, contrasting with the UMN signs seen here. - A **sensory level at T10** and a T8 cord compression on MRI are inconsistent with a purely lumbar cauda equina pathology. *Peripheral neuropathy with concurrent lumbar radiculopathy* - Both **peripheral neuropathy** and **radiculopathy** are **lower motor neuron (LMN) disorders**, which typically cause **reduced or absent reflexes** and do not explain the **brisk reflexes** or **upgoing plantar responses**. - Neither condition would account for a clear **thoracic sensory level** or the specific MRI finding of **spinal cord compression at T8**. *Multiple sclerosis with transverse myelitis* - While **transverse myelitis** can cause UMN signs and a sensory level, the MRI in this case specifically demonstrates **extrinsic cord compression** rather than the demyelinating plaques characteristic of **Multiple Sclerosis**. - The localized back pain and MRI findings strongly suggest a **structural compressive etiology** over an inflammatory demyelinating process. *Motor neuron disease with upper and lower motor neuron signs* - **Motor neuron disease (MND)** is primarily a **motor disorder** and classically does not involve **sensory loss**, which is clearly present with a **sensory level at T10** in this patient. - MND does not cause a **structural compressive lesion** on MRI; the finding of **cord compression at T8** rules out MND as the direct cause of these symptoms.

Question 160: A 68-year-old man with Paget's disease of bone sustains a subtrochanteric femur fracture following a minor fall. What is the most appropriate surgical management for this fracture?

A. Dynamic hip screw fixation
B. Hemiarthroplasty
C. Intramedullary nail fixation (Correct Answer)
D. External fixation as definitive management
E. Total hip replacement

Explanation: ***Intramedullary nail fixation*** - **Intramedullary nail fixation** (specifically cephalomedullary) is the gold standard for **subtrochanteric fractures** as it provides robust **load-sharing** and biomechanical stability against high deforming forces. - In **Paget's disease**, the abnormal bone structure and potential **femoral bowing** are best managed with long intramedullary devices that span the bone and reduce the risk of secondary fractures. *Dynamic hip screw fixation* - **Dynamic hip screws** (DHS) are poorly suited for subtrochanteric fractures due to the high **tensile stresses** on the lateral cortex, which often lead to hardware failure or non-union. - This extramedullary device does not offer the same mechanical advantage as a nail in the presence of **disorganized remodeling** characteristic of Pagetoid bone. *Hemiarthroplasty* - **Hemiarthroplasty** is indicated for **intracapsular femoral neck fractures** in elderly patients, not for fractures occurring distal to the lesser trochanter. - It does not address a **subtrochanteric fracture** which is located within the femoral shaft and requires stabilization rather than joint replacement. *External fixation as definitive management* - **External fixation** is typically reserved for **damage control orthopaedics** in polytrauma patients or severe open fractures, not as a primary treatment for pathological fractures. - It provides inferior stability for long-term healing and carries a high risk of **pin-site infection** and non-union in structurally weak Pagetoid bone. *Total hip replacement* - **Total hip replacement** is unsuitable for a primary fracture located 5 cm distal to the lesser trochanter as it does not stabilize the **subtrochanteric segment**. - While Paget's patients may eventually need THR for **secondary osteoarthritis**, it is not the indicated management for an acute subtrochanteric shaft fracture.

Question 161: A 44-year-old woman presents with chronic lower back pain. MRI lumbar spine shows a high-intensity zone (HIZ) in the posterior annulus fibrosus of the L4/L5 intervertebral disc. What does a high-intensity zone on T2-weighted MRI sequences most likely represent?

A. Normal appearance of well-hydrated nucleus pulposus
B. Annular tear with granulation tissue or fluid accumulation (Correct Answer)
C. Sequestrated disc fragment with epidural extension
D. Calcification within a degenerated intervertebral disc
E. Vertebral endplate oedema (Modic type I change)

Explanation: ***Annular tear with granulation tissue or fluid accumulation***- A **high-intensity zone (HIZ)** on T2-weighted MRI, particularly in the **posterior annulus fibrosus**, is a classic sign of a **radial annular tear**.- This hyperintensity represents an accumulation of **vascularized granulation tissue**, inflammatory exudates, or fluid within the tear, which can be a source of **discogenic pain**.*Normal appearance of well-hydrated nucleus pulposus*- While the **nucleus pulposus** is normally bright (high intensity) on T2-weighted MRI due to its high water content, an **HIZ** is a distinct pathology within the **annulus fibrosus**.- The annulus fibrosus is typically dark on T2, so a focal bright signal within it is abnormal, unlike the uniformly bright central nucleus.*Sequestrated disc fragment with epidural extension*- A **sequestrated disc fragment** involves disc material that has extruded, detached from the parent disc, and moved into the **epidural space**.- An **HIZ** is an intramural finding confined within the substance of the **annulus fibrosus** itself and does not represent a free fragment in the epidural space.*Calcification within a degenerated intervertebral disc*- **Calcification** within any tissue, including the intervertebral disc, typically appears as a **low signal intensity** (dark) on both T1 and T2-weighted MRI sequences.- The term "high-intensity zone" describes a bright signal, which is the opposite of what would be seen with **calcification**.*Vertebral endplate oedema (Modic type I change)*- **Modic Type I changes** refer to **inflammatory oedema** and vascularization of the **vertebral bone marrow** adjacent to the endplates, appearing bright on T2-weighted images.- An **HIZ** is a specific finding within the **annulus fibrosus** of the intervertebral disc, not within the vertebral bone marrow.

Question 162: An 82-year-old woman with advanced dementia (Abbreviated Mental Test Score 3/10) and complete functional dependence sustains a displaced intracapsular neck of femur fracture. Pre-injury, she was bed-bound, doubly incontinent, and residing in a nursing home. What is the most appropriate management strategy?

A. Total hip replacement to provide best functional outcome
B. Internal fixation with cannulated screws to preserve native anatomy
C. Cemented hemiarthroplasty under general anaesthesia
D. Non-operative management with analgesia and palliative care approach (Correct Answer)
E. Delay surgery until medical optimization achieves ASA grade 2

Explanation: ***Non-operative management with analgesia and palliative care approach*** - In patients who were **pre-injury bed-bound** with **advanced dementia** and complete functional dependence, the goal of care shifts from mobilization to **palliative comfort** and dignity. - The risks of surgery and anesthesia in such a frail patient often outweigh the benefits, making a **multidisciplinary approach** to pain relief and nursing care the most appropriate choice. *Total hip replacement to provide best functional outcome* - **Total hip replacement (THR)** is indicated for patients who are **cognitively intact** and able to walk independently pre-injury to achieve better long-term outcomes. - This patient’s **AMTS of 3/10** and pre-injury bed-bound status make her an unsuitable candidate for such an invasive and rehabilitative procedure. *Internal fixation with cannulated screws to preserve native anatomy* - **Internal fixation** is generally reserved for **undisplaced fractures** or younger patients where the preservation of the femoral head is a priority. - In **displaced intracapsular fractures** in the elderly, fixation carries a high risk of **avascular necrosis (AVN)** and re-operation, making it inappropriate here. *Cemented hemiarthroplasty under general anaesthesia* - While **cemented hemiarthroplasty** is the standard surgical treatment for displaced fractures in elderly patients with limited mobility, it is intended to facilitate **early weight-bearing**. - Since the patient was already **non-ambulatory**, the physiological stress of surgery provides no functional benefit while increasing the risk of perioperative mortality. *Delay surgery until medical optimization achieves ASA grade 2* - Delaying surgery for specialized optimization is often futile in patients with **severe frailty** and advanced dementia where the **ASA grade** is unlikely to significantly improve. - Guidelines emphasize that patients requiring surgery should ideally be operated on within **36 hours**, but if surgery is not in the patient's **best interest**, delay for optimization is irrelevant.

Question 163: A 55-year-old woman presents with a 4-month history of lower back pain, morning stiffness lasting 90 minutes, and night pain that improves with activity. She has bilateral buttock pain alternating sides. Examination reveals reduced lumbar flexion with a positive Schober's test. ESR is 42 mm/hr. Radiographs show bilateral sacroiliitis. What is the most appropriate initial pharmacological management?

A. Commence methotrexate as first-line disease-modifying therapy
B. Prescribe high-dose NSAIDs (such as naproxen) as first-line treatment (Correct Answer)
C. Commence tumour necrosis factor-alpha (TNF-α) inhibitor therapy
D. Prescribe oral prednisolone 40 mg daily with gradual taper
E. Commence sulfasalazine as first-line disease-modifying agent

Explanation: ***Prescribe high-dose NSAIDs (such as naproxen) as first-line treatment*** - **NSAIDs** are the gold standard first-line treatment for **axial spondyloarthropathy**, providing both rapid symptomatic relief and potentially slowing radiographic progression. - Guidelines recommend utilizing at least two different NSAIDs at **maximum tolerated doses** for a minimum of 2-4 weeks each before considering biological therapies. *Commence methotrexate as first-line disease-modifying therapy* - **Methotrexate** has no proven efficacy in treating the **axial (spinal)** manifestations of ankylosing spondylitis. - It is primarily reserved for patients with **peripheral joint involvement**, which is not the primary presentation in this case. *Commence tumour necrosis factor-alpha (TNF-α) inhibitor therapy* - **TNF-α inhibitors** (such as adalimumab) are second-line agents indicated only after the failure or intolerance of at least two different **NSAIDs**. - While highly effective, they are not initiated first-line due to cost, potential **immunosuppressive side effects**, and strict eligibility criteria. *Prescribe oral prednisolone 40 mg daily with gradual taper* - **Systemic corticosteroids** like prednisolone are generally ineffective for long-term management of **axial symptoms** in spondyloarthropathy. - Chronic use is avoided due to the high risk of **side effects** and lack of evidence for modifying the disease course in the spine. *Commence sulfasalazine as first-line disease-modifying agent* - **Sulfasalazine** is a conventional synthetic DMARD that, like methotrexate, is only effective for **peripheral arthritis**. - It shows no clinical benefit for the **axial disease** (sacroiliitis and spondylitis) described in this patient's clinical and radiographic presentation.

Question 164: A 71-year-old man undergoes dynamic hip screw fixation for an intertrochanteric neck of femur fracture. Post-operatively, the tip-apex distance (TAD) is measured on radiographs. What measurement of TAD is associated with the highest risk of cut-out of the lag screw?

A. 20-25 mm
B. Less than 15 mm
C. 15-20 mm
D. Greater than 25 mm (Correct Answer)
E. Greater than 30 mm

Explanation: ***Greater than 25 mm*** - A **Tip-Apex Distance (TAD)** greater than **25 mm** indicates that the lag screw is poorly positioned within the **femoral head**, increasing the leverage forces on the screw. - This suboptimal placement, specifically being too far from the **subchondral bone**, significantly elevates the risk of **mechanical failure** and **lag screw cut-out** from the femoral head. *Less than 15 mm* - A TAD of **less than 15 mm** typically signifies a deeply placed screw, which provides good purchase in the bone but can increase the risk of **joint penetration** or **avascular necrosis** of the femoral head. - This measurement is generally considered to be in a favorable zone for preventing cut-out, as the screw has **maximal stability** within the bone. *15-20 mm* - This range for TAD is widely accepted as the **ideal placement zone** for a lag screw in dynamic hip screw (DHS) fixation. - It optimizes **mechanical stability** by providing sufficient bone purchase while minimizing the risk of both cut-out and articular surface penetration. *20-25 mm* - While closer to the upper limit, a TAD within the **20-25 mm** range is still generally considered **acceptable** in many orthopedic practices. - The risk of cut-out begins to increase in this zone but becomes significantly higher and clinically concerning once the measurement **exceeds 25 mm**. *Greater than 30 mm* - Although a TAD **greater than 30 mm** certainly represents a very high risk for cut-out, the established **critical threshold** where the risk significantly escalates is traditionally defined as **greater than 25 mm**. - This option is still incorrect because **greater than 25 mm** is the *minimal* established cut-off that signifies a high risk, making it the most appropriate answer for the question's premise.

Question 165: A 48-year-old woman with metastatic renal cell carcinoma presents with a 3-week history of severe lower back pain that is constant, worse at night, and not relieved by lying down. Plain radiographs show a lytic lesion in the L3 vertebral body with cortical destruction and >50% vertebral body involvement. What is the most appropriate next step in management?

A. Commence radiotherapy and strong analgesia with urgent orthopaedic outpatient follow-up
B. Arrange urgent CT-guided biopsy to confirm metastatic disease
C. Arrange urgent MRI spine and refer to spinal surgery for consideration of surgical stabilisation (Correct Answer)
D. Prescribe high-dose NSAIDs and bisphosphonate therapy with routine oncology review
E. Commence systemic chemotherapy and arrange elective spinal surgery if symptoms persist

Explanation: ***Arrange urgent MRI spine and refer to spinal surgery for consideration of surgical stabilisation*** - The patient's presentation with **constant, nocturnal back pain**, a known history of **metastatic renal cell carcinoma**, and **lytic lesion with >50% vertebral body involvement** indicates a high risk of **spinal instability** and impending or actual **spinal cord compression**. - An **urgent MRI spine** is crucial to assess the extent of spinal cord involvement, **thecal sac compression**, and overall stability, which will guide the need for **surgical stabilisation** to prevent neurological deficits and manage pain. *Commence radiotherapy and strong analgesia with urgent orthopaedic outpatient follow-up* - Radiotherapy is often used for metastatic spinal lesions but is **less effective for highly vascular and radioresistant tumors like renal cell carcinoma**. More importantly, it **does not address mechanical instability**, which is a primary concern here. - Outpatient follow-up is insufficient for a potentially **unstable spine** with significant vertebral body destruction, as it risks **acute neurological deterioration** while delaying definitive intervention. *Arrange urgent CT-guided biopsy to confirm metastatic disease* - The patient has a **known history of metastatic renal cell carcinoma**, and the radiographic findings of a lytic lesion are consistent with metastatic disease, making a biopsy **unnecessary and delaying critical treatment**. - The priority in this scenario is to assess and manage the **mechanical stability of the spine** and potential **spinal cord compression**, not to reconfirm the diagnosis of metastatic disease. *Prescribe high-dose NSAIDs and bisphosphonate therapy with routine oncology review* - While analgesia (NSAIDs) and bisphosphonates are part of supportive care for bone metastases, they **do not address the underlying spinal instability** or the imminent risk of **pathological fracture and neurological compromise**. - A **routine oncology review** is inadequate for a patient presenting with acute, severe, constant pain and significant vertebral destruction, which requires **urgent intervention** to prevent catastrophic outcomes. *Commence systemic chemotherapy and arrange elective spinal surgery if symptoms persist* - **Renal cell carcinoma is often resistant to conventional chemotherapy**, making this an unlikely primary effective strategy for immediate pain relief or spinal stabilization. - **Elective spinal surgery** is inappropriate for an unstable spine at high risk of collapse; intervention needs to be **urgent and proactive** to prevent irreversible neurological damage, not reactive after symptom persistence.

Question 166: A 72-year-old man with an undisplaced Garden I intracapsular neck of femur fracture undergoes internal fixation with cannulated screws. What is the primary rationale for performing internal fixation rather than arthroplasty in this patient?

A. Internal fixation has lower risk of infection compared to arthroplasty
B. Undisplaced fractures have intact blood supply with lower risk of avascular necrosis, preserving native anatomy (Correct Answer)
C. Internal fixation requires shorter operative time and is safer for elderly patients
D. Cannulated screws provide superior biomechanical stability compared to arthroplasty
E. Internal fixation eliminates the need for post-operative anticoagulation

Explanation: ***Undisplaced fractures have intact blood supply with lower risk of avascular necrosis, preserving native anatomy*** - In **Garden I and II** fractures, the **retinacular vessels** are largely intact, significantly reducing the risk of **avascular necrosis (AVN)** compared to displaced fractures. - Internal fixation aims to **preserve the native femoral head**, which is the physiological preference when the risk of non-union or ischemia is low. *Internal fixation has lower risk of infection compared to arthroplasty* - While internal fixation is less invasive, **infection risk** is not the primary clinical factor driving the choice to avoid replacement in stable fractures. - Modern **arthroplasty** techniques have standardized infection protocols, making the biological potential for healing the more critical decision factor. *Internal fixation requires shorter operative time and is safer for elderly patients* - Although fixation is usually faster, **Garden classification**-based management focuses on **fracture biology** and blood supply rather than just surgical duration. - Standard of care for **displaced** fractures in similarly aged patients is still arthroplasty, despite the longer operative time, due to the high failure rate of fixation in those cases. *Cannulated screws provide superior biomechanical stability compared to arthroplasty* - Arthroplasty actually provides **superior immediate stability** and typically allows for **immediate full weight-bearing**, which is vital for elderly recovery. - Cannulated screws rely on **secondary bone healing** and the intrinsic stability of the impacted or non-displaced fracture pattern. *Internal fixation eliminates the need for post-operative anticoagulation* - All hip fracture surgeries, regardless of the implant used, require **post-operative thromboprophylaxis** to prevent deep vein thrombosis and pulmonary embolism. - The risk of **venous thromboembolism (VTE)** is high in hip surgery patients due to immobility and the systemic inflammatory response, regardless of the fixation method.

Question 167: A 67-year-old woman presents with a 6-week history of lower back pain radiating to both legs. The pain is worse on walking and relieved by sitting or leaning forward. She reports that she can walk further when pushing a shopping trolley. Peripheral pulses are normal. What is the most likely diagnosis?

A. Lumbar disc herniation with bilateral radiculopathy
B. Peripheral vascular disease with intermittent claudication
C. Lumbar spinal stenosis with neurogenic claudication (Correct Answer)
D. Cauda equina syndrome
E. Degenerative spondylolisthesis

Explanation: ***Lumbar spinal stenosis with neurogenic claudication***- The classic **'shopping trolley sign'** occurs because leaning forward (lumbar flexion) increases the **cross-sectional area** of the spinal canal, relieving pressure on the neural elements.- This patient presents with **neurogenic claudication**, characterized by bilateral leg pain induced by walking and relieved by sitting or leaning forward, typically seen in older patients with **degenerative changes**.*Lumbar disc herniation with bilateral radiculopathy*- This typically presents with **acute onset** of pain that is often **worsened by flexion** (sitting or bending forward), which is the opposite of this patient's presentation.- Bilateral radiculopathy from a disc is rare and usually associated with a large **central disc protrusion** rather than chronic walking-induced symptoms.*Peripheral vascular disease with intermittent claudication*- While both cause leg pain on walking, vascular claudication is relieved simply by **standing still**, whereas neurogenic claudication requires **spinal flexion** (sitting or leaning).- The presence of **normal peripheral pulses** and the 'shopping trolley sign' effectively rule out peripheral arterial disease as the cause.*Cauda equina syndrome*- This is a surgical emergency characterized by **saddle anesthesia**, **bladder/bowel dysfunction** (e.g., urinary retention), and profound motor weakness.- While stenosis can lead to this, the patient's 6-week history of **position-dependent pain** without neurological emergencies makes it an unlikely primary diagnosis.*Degenerative spondylolisthesis*- Although this condition can lead to spinal stenosis, it refers specifically to the **slippage of one vertebra** over another, usually seen at the L4-L5 level.- While it is a potential cause, **lumbar spinal stenosis** is the most accurate clinical description for the syndrome of neurogenic claudication described.

Question 168: A 78-year-old woman undergoes hemiarthroplasty for a displaced intracapsular neck of femur fracture. Six hours post-operatively, she develops acute shortness of breath, hypoxia (SpO2 88% on room air), tachycardia (110 bpm), and confusion. Blood pressure is 95/60 mmHg. She has a petechial rash on her chest and conjunctival petechiae. What is the most likely diagnosis?

A. Pulmonary embolism secondary to deep vein thrombosis
B. Fat embolism syndrome (Correct Answer)
C. Bone cement implantation syndrome
D. Hospital-acquired pneumonia
E. Acute myocardial infarction

Explanation: ***Fat embolism syndrome*** - This patient presents with the classic triad of acute **respiratory distress** (shortness of breath, hypoxia), **neurological impairment** (confusion), and a **petechial rash** (on chest and conjunctiva), which is highly characteristic of fat embolism syndrome. - It commonly occurs within **12-72 hours** after **long bone fractures** (like a neck of femur fracture) or orthopaedic procedures due to the release of fat globules into the circulation. *Pulmonary embolism secondary to deep vein thrombosis* - While a PE can cause acute **shortness of breath**, **hypoxia**, and **tachycardia**, it typically does not present with a **petechial rash** or profound acute confusion as primary features. - PE usually develops later in the post-operative period, often **days to weeks** after surgery, rather than within six hours. *Bone cement implantation syndrome* - This syndrome typically occurs **intraoperatively** during the pressurization of bone cement, leading to sudden **hypotension**, hypoxia, and cardiac events, occasionally cardiac arrest. - It does not present with the delayed development of a **petechial rash** or the specific constellation of symptoms seen six hours post-operatively. *Hospital-acquired pneumonia* - Hospital-acquired pneumonia typically develops **48 hours or more** after hospital admission or surgery, making its onset within six hours highly unlikely. - While it causes respiratory symptoms, it is characterized by fever, cough, and infiltrates on chest imaging, and does not cause a **petechial rash**. *Acute myocardial infarction* - An AMI can cause **tachycardia**, **hypotension**, and hypoxia, but it is typically associated with **chest pain**, specific ECG changes, and elevated cardiac biomarkers. - It would not explain the presence of a **petechial rash** and is less likely in the immediate post-operative setting of a femur fracture without other typical cardiac signs.

Question 169: A 58-year-old man with a history of tuberculosis 20 years ago presents with a 4-month history of progressively worsening lower back pain. The pain is constant, worse at night, and not relieved by rest. He reports unintentional weight loss of 8 kg and night sweats. ESR is 78 mm/hr and CRP is 45 mg/L. What is the most likely underlying diagnosis?

A. Mechanical lower back pain with deconditioning
B. Ankylosing spondylitis
C. Spinal tuberculosis (Pott's disease) (Correct Answer)
D. Metastatic spinal malignancy
E. Lumbar disc prolapse with radiculopathy

Explanation: ***Spinal tuberculosis (Pott's disease)***- The patient's history of **prior tuberculosis**, combined with **constitutional symptoms** like night sweats and weight loss, strongly suggests reactivation of TB in the spine.- The **elevated inflammatory markers** (ESR/CRP) and **nocturnal pain** that is not relieved by rest are classic red flags for an infectious or inflammatory process like **Pott's disease**.*Mechanical lower back pain with deconditioning*- **Mechanical back pain** is typically relieved by rest and does not present with **systemic symptoms** like weight loss or night sweats.- It would not explain the significantly elevated **ESR and CRP** levels seen in this clinical presentation.*Ankylosing spondylitis*- This condition usually presents in **younger patients** and is characterized by pain and stiffness that **improves with activity**, unlike this patient's worsening symptoms.- While it involves the spine, it does not typically cause **unintentional weight loss** or follow a history of tuberculosis infection.*Metastatic spinal malignancy*- While malignancy causes **nocturnal pain** and weight loss, the 20-year history of **tuberculosis** makes infectious spondylitis a more specific consideration.- Distinguishing between the two often requires imaging and biopsy, but the **prior TB exposure** serves as a strong diagnostic clue for Pott's disease.*Lumbar disc prolapse with radiculopathy*- This typically presents with **acute onset** radicular pain (sciatica) following a dermatomal pattern rather than **constant night pain**.- Disc prolapse is a mechanical issue and is not associated with **fever**, night sweats, or elevated systemic **inflammatory markers**.

Question 170: Which of the following best describes the Garden classification system for intracapsular neck of femur fractures?

A. Classification based on the anatomical location of the fracture relative to the trochanters
B. Classification based on the degree of displacement and alignment of trabecular patterns on anteroposterior radiograph (Correct Answer)
C. Classification based on the angle of the fracture line relative to the horizontal plane
D. Classification based on the mechanism of injury and patient age
E. Classification based on the presence or absence of comminution at the fracture site

Explanation: ***Classification based on the degree of displacement and alignment of trabecular patterns on anteroposterior radiograph*** - The **Garden Classification** uses the alignment of the **medial femoral neck trabeculae** on an AP radiograph to categorize intracapsular fractures into four stages (I to IV). - It is critical for clinical decision-making, specifically distinguishing between **undisplaced** (I and II) and **displaced** (III and IV) fractures, which guides surgical approach and assesses the risk of **avascular necrosis**. *Classification based on the anatomical location of the fracture relative to the trochanters* - This describes broader **anatomical classifications** of hip fractures (e.g., subcapital, transcervical, basicervical, intertrochanteric, subtrochanteric) rather than the specific Garden system. - The Garden system specifically applies to **intracapsular** fractures and categorizes them based on displacement, not their general position relative to the trochanters. *Classification based on the angle of the fracture line relative to the horizontal plane* - This describes the **Pauwels classification**, which assesses the **verticality** or shear angle of the fracture line. - Higher Pauwels angles (Type III) indicate greater **shear forces** and a higher risk of non-union, whereas Garden focuses on the degree of displacement and impaction. *Classification based on the mechanism of injury and patient age* - While patient age and **mechanism of injury** (e.g., high-energy trauma vs. low-energy fall) are crucial for overall clinical assessment and treatment planning, they are not the criteria used for the Garden radiographic classification. - The Garden system relies purely on **radiographic signs** of displacement and trabecular alignment to grade the fracture. *Classification based on the presence or absence of comminution at the fracture site* - **Comminution** (fragmentation) is an important feature in classifying many fractures, particularly **extracapsular fractures** like those using the Evans classification for intertrochanteric fractures. - The Garden classification, however, focuses on the **angular displacement** and impaction of the femoral head relative to the neck, rather than the number or size of bone fragments.

Question 171: A 62-year-old man presents to the Emergency Department with a 24-hour history of severe lower back pain and inability to pass urine. On examination, he has reduced anal tone, absent bulbocavernosus reflex, and bilateral lower limb weakness. Perianal sensation is diminished. What is the most appropriate immediate management?

A. Arrange urgent MRI spine within 1 week and prescribe analgesia
B. Refer for urgent neurosurgical assessment and arrange emergency MRI spine within 4 hours (Correct Answer)
C. Prescribe high-dose oral prednisolone and arrange outpatient MRI
D. Insert urinary catheter and arrange routine orthopaedic outpatient review
E. Arrange urgent CT lumbar spine and commence intravenous antibiotics

Explanation: ***Refer for urgent neurosurgical assessment and arrange emergency MRI spine within 4 hours***- The patient presents with classic signs of **Cauda Equina Syndrome (CES)**, including urinary retention, **saddle anesthesia**, reduced **anal tone**, and **lower limb weakness**, which requires immediate diagnosis to prevent permanent disability.- **Emergency MRI** is the gold standard investigation and must be performed within hours to facilitate urgent **surgical decompression** by neurosurgery or orthopedics.*Arrange urgent MRI spine within 1 week and prescribe analgesia*- A one-week delay is inappropriate for a **neurosurgical emergency** like CES; waiting this long leads to irreversible **nerve damage** and chronic incontinence.- While **analgesia** is helpful for comfort, it does not address the underlying mechanical compression of the **cauda equina** nerve roots.*Prescribe high-dose oral prednisolone and arrange outpatient MRI*- **Prednisolone** is primarily used for **Metastatic Spinal Cord Compression (MSCC)**, not as the primary treatment for disk-related **Cauda Equina Syndrome**.- Outpatient management is contraindicated given the acute onset of **motor weakness** and **sphincter dysfunction**, which require immediate intervention.*Insert urinary catheter and arrange routine orthopaedic outpatient review*- While **catheterization** manages urinary retention, it is purely symptomatic and does not provide the necessary **decompressive surgery** to restore nerve function.- Routine review is insufficient; the prognosis for recovery drops significantly if decompression is delayed beyond **24-48 hours**.*Arrange urgent CT lumbar spine and commence intravenous antibiotics*- **MRI** is significantly more sensitive than **CT** for identifying soft tissue issues like **disc herniations** or hematomas that cause spinal root compression.- **Antibiotics** are only indicated if there is suspicion of **spinal epidural abscess** (e.g., fever, elevated CRP, recent infection), which is not the primary suspicion in this clinical presentation.

Question 172: A 74-year-old woman sustains a neck of femur fracture following a fall. An anteroposterior pelvic radiograph shows a fracture line extending from the femoral head-neck junction towards the greater trochanter, located entirely distal to the insertion of the hip joint capsule. Which anatomical classification best describes this fracture pattern?

A. Intracapsular subcapital fracture
B. Intracapsular transcervical fracture
C. Basicervical fracture
D. Intertrochanteric fracture (Correct Answer)
E. Subtrochanteric fracture

Explanation: ***Intertrochanteric fracture***- These fractures occur between the **greater and lesser trochanters** and are located **extracapsularly**, distal to the hip joint capsule insertion.- Because they are outside the capsule, they have a **better blood supply** and lower risk of avascular necrosis compared to intracapsular fractures.*Intracapsular subcapital fracture*- This fracture occurs immediately **distal to the femoral head** and is located entirely within the joint capsule.- It carries a high risk of **avascular necrosis** due to disruption of the primary blood supply to the femoral head.*Intracapsular transcervical fracture*- Located across the **mid-portion of the femoral neck**, this pattern remains within the hip joint capsule.- Like other intracapsular fractures, it is associated with a high rate of **non-union** and damage to the retinacular vessels.*Basicervical fracture*- This fracture occurs at the **base of the femoral neck** exactly at the junction of the neck and the trochanters.- Since it occurs at the **capsular insertion line**, it is often biomechanically treated similarly to extracapsular fractures.*Subtrochanteric fracture*- This pattern describes a fracture located in the region **distal to the lesser trochanter**, extending into the proximal femoral shaft.- These are characterized by high mechanical stress and are typically managed with **intramedullary nails**.

Question 173: A 52-year-old man with a 15-year history of chronic lower back pain presents with new onset bilateral leg weakness, saddle paraesthesia, and urinary retention that developed over 24 hours. On examination, there is bilateral leg weakness (4/5), absent ankle reflexes, reduced perianal sensation, and a palpable bladder. Post-void residual volume is 800 ml. What is the timeframe within which surgical decompression should ideally be performed to optimize neurological recovery?

A. Within 6 hours of symptom onset
B. Within 24 hours of symptom onset
C. Within 48 hours of symptom onset (Correct Answer)
D. Within 72 hours of symptom onset
E. Within 1 week of symptom onset

Explanation: ***Within 48 hours of symptom onset*** - This timeframe is crucial for **Cauda Equina Syndrome (CES)**, as surgical decompression within **48 hours** is strongly associated with improved recovery of **bladder, bowel, and motor functions**. - Early intervention within this window aims to prevent **irreversible neurological damage** by relieving pressure on the cauda equina nerves. *Within 6 hours of symptom onset* - While earlier decompression is often desired, a **6-hour window** is not a universally accepted or practical guideline for optimal recovery in CES, which can be challenging to diagnose rapidly. - This very tight timeframe is not supported by current evidence as being significantly superior to the **48-hour** window for overall neurological outcomes. *Within 24 hours of symptom onset* - Decompression within **24 hours** is considered excellent and generally yields very good outcomes, particularly if **complete urinary retention** has not yet occurred. - However, the critical threshold for significantly worsening prognosis is often cited as beyond **48 hours**, making 24 hours an ideal but not strictly mandatory cutoff for optimal results compared to the 48-hour benchmark. *Within 72 hours of symptom onset* - Delaying surgical decompression beyond **48 hours** and into the **72-hour** mark significantly increases the risk of permanent **neurological deficits**, including persistent **urinary and bowel dysfunction** and sensory loss. - The chances of achieving full recovery of **bladder and bowel function** diminish substantially with such delays. *Within 1 week of symptom onset* - Surgical intervention after **one week** is considered a **late decompression** and is often associated with poor recovery of **sphincter function** and significant residual **motor and sensory deficits**. - Prolonged compression for this duration frequently leads to **irreversible nerve damage** and permanent disability.

Question 174: A 71-year-old man sustains an undisplaced basicervical neck of femur fracture. He is cognitively intact, independently mobile, and medically fit. Surgical management is planned. Which fixation device is most biomechanically appropriate for this fracture pattern?

A. Cannulated hip screws
B. Dynamic hip screw with derotation screw (Correct Answer)
C. Intramedullary nail
D. Total hip replacement
E. Proximal femoral locking plate

Explanation: ***Dynamic hip screw with derotation screw***- **Basicervical fractures** are biomechanically unstable fractures at the base of the femoral neck, resembling **extracapsular** patterns, which benefit from the controlled **sliding compression** and lateral plate support provided by a **Dynamic Hip Screw (DHS)**.- An additional **derotation screw** prevents rotational instability of the femoral head during and after fixation, ensuring enhanced stability and improving healing potential. *Cannulated hip screws*- These screws are best suited for **undisplaced intracapsular** fractures (subcapital or transcervical) where the fracture geometry allows for stable compression.- They lack the **lateral plate** that provides essential buttress support against **varus collapse** common in basicervical fractures, making them biomechanically inadequate for this fracture pattern. *Intramedullary nail*- **Intramedullary nails** are primarily indicated for **subtrochanteric** or unstable **intertrochanteric fractures**, especially those with a **reverse oblique** component.- For a simple undisplaced basicervical fracture, a **DHS** is typically sufficient and often less invasive than an intramedullary nail, which may introduce greater surgical morbidity without additional biomechanical advantage for this specific fracture. *Total hip replacement*- This procedure is usually reserved for **displaced intracapsular** fractures in elderly patients or those with significant **pre-existing osteoarthritis** or poor bone quality, to mitigate the risk of **avascular necrosis**.- For an **undisplaced fracture** in a cognitively intact, independently mobile patient, the goal is to preserve the native hip joint through **internal fixation**, not immediate arthroplasty. *Proximal femoral locking plate*- **Locking plates** provide a rigid construct that may lead to **stress shielding**, potentially hindering the natural biological healing process which benefits from controlled micromotion.- They are typically reserved for **complex comminuted fractures**, **periprosthetic fractures**, or **revision surgeries** where other fixation methods have failed, not as a primary treatment for a basicervical fracture.

Question 175: A 35-year-old man presents to the Emergency Department with sudden onset severe lower back pain that began 3 hours ago when lifting furniture. He describes the pain as 7/10 in severity, localized to the lumbar region with no radiation. He can walk, has no bladder or bowel symptoms, and neurological examination is completely normal. He is apyrexial. What is the most appropriate immediate management?

A. Urgent MRI lumbar spine
B. Plain radiographs of lumbar spine
C. Analgesia, reassurance, and advice to remain active (Correct Answer)
D. Strict bed rest for 2 weeks
E. Referral to spinal surgery

Explanation: ***Analgesia, reassurance, and advice to remain active*** - The patient presents with **acute mechanical lower back pain** following a physical strain, without any **red flag features** such as neurological deficits, fever, bladder/bowel dysfunction, or pain radiating below the knee. - Current guidelines for acute non-specific low back pain emphasize **pain management**, **reassurance**, and encouraging **early mobilization** and return to normal activities, as this promotes faster recovery and reduces chronicity. *Urgent MRI lumbar spine* - **Urgent MRI** is indicated only when there are **red flag symptoms** suggesting serious pathology like **cauda equine syndrome**, malignancy, or spinal infection, none of which are present here. - Routine imaging for acute, uncomplicated back pain rarely changes management and can lead to **unnecessary anxiety** and investigations due to incidental findings. *Plain radiographs of lumbar spine* - **Plain radiographs** are generally not recommended for acute low back pain in the absence of trauma or suspicion of conditions like **vertebral fracture**, infection, or malignancy. - They have **limited utility** for soft tissue abnormalities (like disc herniation) and expose the patient to **radiation** without significant clinical benefit in this scenario. *Strict bed rest for 2 weeks* - **Strict bed rest** is contraindicated for acute low back pain as it can delay recovery, lead to **deconditioning**, muscle weakness, and increased risk of **chronic pain**. - Maintaining activity within pain limits and **early mobilization** are crucial for recovery and preventing long-term disability. *Referral to spinal surgery* - **Referral to spinal surgery** is typically reserved for patients with progressive **neurological deficits**, **cauda equine syndrome**, or severe, intractable pain that has failed prolonged conservative management. - Given the patient's **normal neurological examination** and acute presentation, surgical intervention is not indicated at this stage.

Question 176: A 76-year-old woman with a displaced intracapsular neck of femur fracture undergoes cemented hemiarthroplasty. She has a history of chronic kidney disease stage 4 (eGFR 25 ml/min/1.73m²). Post-operatively, the multidisciplinary team is planning thromboprophylaxis. What is the most appropriate thromboprophylaxis regimen for this patient?

A. Low molecular weight heparin at full treatment dose
B. Unfractionated heparin subcutaneously (Correct Answer)
C. Rivaroxaban 10 mg once daily
D. Aspirin 75 mg once daily
E. Mechanical prophylaxis only with intermittent pneumatic compression

Explanation: ***Unfractionated heparin subcutaneously*** - In patients with **severe renal impairment** (eGFR <30 ml/min/1.73m²), **Unfractionated Heparin (UFH)** is the preferred pharmacological agent as it is not primarily eliminated by the kidneys. - This avoids the risk of **drug accumulation** and subsequent major bleeding complications that occur with renally excreted anticoagulants in CKD stage 4 patients. *Low molecular weight heparin at full treatment dose* - **Low molecular weight heparin (LMWH)** is predominantly **renally excreted**, and its half-life is significantly prolonged in patients with an eGFR below 30. - Furthermore, **prophylactic doses**, not full treatment doses, are indicated for post-operative VTE prevention in stable patients. *Rivaroxaban 10 mg once daily* - This **Direct Oral Anticoagulant (DOAC)** is contraindicated or not recommended for VTE prophylaxis when the **eGFR is less than 30 ml/min/1.73m²**. - Using DOACs in severe CKD significantly increases the **risk of hemorrhage** due to decreased renal clearance of the drug. *Aspirin 75 mg once daily* - While antiplatelets have a role in some protocols, **aspirin alone** provides insufficient protection against VTE following high-risk procedures like hip fracture surgery. - Current guidelines favor **anticoagulants** over antiplatelets for chemical prophylaxis in the immediate post-operative period for orthopedic trauma. *Mechanical prophylaxis only with intermittent pneumatic compression* - **Mechanical prophylaxis** is generally used as an adjunct to pharmacological methods rather than a standalone treatment for high-risk hip surgeries. - It is only used as **monotherapy** if there is an absolute contraindication to all forms of pharmacological anticoagulation, which is not stated here.

Question 177: A 43-year-old woman presents with a 12-week history of lower back pain radiating to the lateral aspect of her right thigh and leg. She describes tingling over the dorsum of her foot and reports difficulty with foot dorsiflexion when walking. Examination reveals weakness of right ankle dorsiflexion (4/5 power), diminished sensation over the first web space, and a positive straight leg raise at 40 degrees on the right. What is the most likely nerve root affected?

A. L3
B. L4
C. L5 (Correct Answer)
D. S1
E. S2

Explanation: ***L5*** - The **L5 nerve root** is responsible for sensory innervation of the **first web space** and the **dorsum of the foot**, which matches the patient's tingling and sensory deficit. - Weakness in **ankle dorsiflexion** and difficulty with **foot dorsiflexion** when walking are classic motor signs of **L5 radiculopathy**, typically caused by an **L4-L5 disc herniation**. *L3* - **L3 radiculopathy** typically presents with pain and sensory loss over the **anterior thigh** and the medial aspect of the knee. - It is associated with weakness in **hip flexion** and **knee extension**, along with a potentially diminished **patellar reflex**. *L4* - The **L4 nerve root** provides sensation to the **medial malleolus** and medial leg rather than the first web space. - While it contributes to ankle dorsiflexion, a deficit here usually presents with a loss of the **knee-jerk reflex**, which is not mentioned. *S1* - **S1 nerve root** compression typically causes weakness in **plantarflexion** and a loss of the **calcaneal (ankle) reflex**. - Sensory loss in S1 radiculopathy is localized to the **lateral foot** and the small toe, which contradicts this patient's symptoms. *S2* - **S2 radiculopathy** is rare and generally results in sensory deficits over the **posterior thigh** or the popliteal fossa. - It does not involve dorsiflexion of the foot and is more often associated with **cauda equina syndrome** if presenting with bowel/bladder dysfunction.

Question 178: A 68-year-old man undergoes dynamic hip screw fixation for an intertrochanteric femur fracture. Post-operatively, the tip-apex distance (TAD) is measured on the AP and lateral radiographs. What is the maximum acceptable tip-apex distance to minimize the risk of screw cut-out?

A. 15 mm
B. 20 mm
C. 25 mm (Correct Answer)
D. 30 mm
E. 35 mm

Explanation: ***25 mm*** - The **Tip-Apex Distance (TAD)** is a critical measurement for predicting **lag screw cut-out** in intertrochanteric femur fractures. - A TAD of **25 mm or less** is widely accepted as the maximum acceptable distance to minimize the risk of screw cut-out, according to the **Baumgaertner criteria**. *15 mm* - While a TAD of 15 mm indicates an **excellent screw position** and provides high mechanical stability, it is not the *maximum acceptable* limit but rather a highly optimal target. - This value is well within the safe zone, significantly reducing the risk of **fixation failure**. *20 mm* - A TAD of 20 mm also represents a **safe and good screw placement**, offering a low risk of cut-out. - Like 15 mm, it is not the *maximum acceptable* limit but falls comfortably below the critical threshold of **25 mm**. *30 mm* - A TAD of **30 mm** is greater than the accepted maximum of 25 mm and significantly increases the risk of **lag screw cut-out**. - This distance suggests the screw is positioned too far from the **subchondral bone** of the femoral head, leading to less stable fixation. *35 mm* - A TAD of **35 mm** represents a very poor and unsafe screw position, indicative of **suboptimal surgical technique**. - Such a high TAD is associated with a substantially increased risk of **fixation failure** and other post-operative complications.

Question 179: A 55-year-old woman presents with a 2-week history of severe lower back pain. She has a past medical history of breast cancer treated 3 years ago with mastectomy and adjuvant chemotherapy. Examination reveals tenderness over L3 vertebra. Plain radiographs show a lytic lesion in the L3 vertebral body with >50% vertebral body collapse but no posterior element involvement. Neurological examination is normal. MRI confirms isolated L3 involvement without cord compression. What is the most appropriate initial treatment?

A. Urgent surgical decompression and stabilization
B. Radiotherapy alone
C. Vertebroplasty or balloon kyphoplasty (Correct Answer)
D. High-dose oral corticosteroids
E. Conservative management with bed rest

Explanation: ***Vertebroplasty or balloon kyphoplasty*** - These minimally invasive procedures are highly effective for **mechanical stabilization** and **pain relief** in patients with symptomatic pathological fractures with >50% collapse but no neurological deficit. - By injecting bone cement into the L3 body, it addresses the **mechanical instability** caused by the metastatic lytic lesion while allowing for rapid mobilization. *Urgent surgical decompression and stabilization* - This intervention is primarily indicated for patients with **spinal cord compression**, significant **neurological deficits**, or severe **spinal instability** involving the posterior elements. - As the patient's **neurological examination is normal** and MRI confirms **no cord compression**, this aggressive surgical approach is not the initial treatment of choice. *Radiotherapy alone* - While **radiotherapy** is crucial for **local tumor control** and can alleviate pain, it does not immediately provide structural support to a collapsed vertebral body. - For a vertebral body with **>50% collapse**, relying solely on radiotherapy risks continued mechanical pain and further structural deterioration before the anti-tumor effects manifest. *High-dose oral corticosteroids* - Corticosteroids are typically used in the setting of **metastatic spinal cord compression (MSCC)** to reduce **vasogenic edema** and relieve pressure on the cord. - Given that the MRI shows **no cord compression** and the neurological examination is normal, high-dose corticosteroids are not indicated and would unnecessarily expose the patient to systemic side effects. *Conservative management with bed rest* - **Bed rest** alone is generally discouraged for symptomatic pathological vertebral fractures due to the risk of complications such as **deep vein thrombosis**, pneumonia, and muscle deconditioning. - It also fails to address the underlying **mechanical instability** and severe pain caused by the **vertebral collapse**, making it an ineffective primary treatment.

Question 180: An 80-year-old man with Paget's disease of bone sustains a minimally displaced intracapsular neck of femur fracture after a fall. He was mobile with a frame pre-injury and has mild cognitive impairment (AMTS 7/10). Blood tests show elevated alkaline phosphatase (850 U/L). What modification to standard surgical management should be considered due to his underlying condition?

A. Avoid cemented arthroplasty due to risk of cement failure
B. Use longer stem prosthesis to bypass pagetic bone (Correct Answer)
C. Perform total hip replacement rather than hemiarthroplasty in all cases
D. Delay surgery for 6 weeks to optimize bone quality with bisphosphonates
E. Avoid arthroplasty and perform internal fixation instead

Explanation: ***Use longer stem prosthesis to bypass pagetic bone*** - In **Paget's disease**, the proximal femur often exhibits abnormal architecture and weakened structure; a **longer stem prosthesis** is used to achieve secure fixation in the **distal normal bone**. - This modification reduces the risk of **periprosthetic fracture** and implant loosening associated with the biomechanically inferior and highly vascular pagetic bone. *Avoid cemented arthroplasty due to risk of cement failure* - **Cemented arthroplasty** is actually often preferred in Paget's disease because the cement provides **immediate stable fixation** in the altered trabecular bone. - There is no evidence that Paget's disease causes **cement failure**; rather, it is the abnormal bone remodeling that risks primary implant stability. *Perform total hip replacement rather than hemiarthroplasty in all cases* - **Total hip replacement (THR)** is typically reserved for patients who are **active**, have no cognitive impairment, and have pre-existing osteoarthritis. - Given this patient's **mild cognitive impairment (AMTS 7/10)** and pre-injury use of a **mobility frame**, a hemiarthroplasty is the more appropriate and less invasive standard. *Delay surgery for 6 weeks to optimize bone quality with bisphosphonates* - Hip fracture surgery should typically be performed within **36 hours** of admission to reduce **morbidity and mortality** associated with prolonged immobility. - While **bisphosphonates** manage Paget’s disease long-term, delaying surgical fixation for weeks in an 80-year-old is medically inappropriate and dangerous. *Avoid arthroplasty and perform internal fixation instead* - **Internal fixation** (such as cannulated screws) is generally avoided in an 80-year-old with a neck of femur fracture due to high rates of **non-union** and **avascular necrosis**. - Arthroplasty allows for **early weight-bearing**, which is vital for elderly patients to prevent complications like pneumonia or pressure sores.

Question 181: A 60-year-old woman presents with a 6-month history of bilateral buttock and posterior thigh pain that worsens after walking 200 metres. The pain is relieved by sitting or leaning forward. She has a history of lumbar spondylosis. Neurological examination of the lower limbs is normal at rest. Peripheral pulses are palpable bilaterally. What is the most likely diagnosis?

A. Peripheral arterial disease
B. Lumbar spinal stenosis (Correct Answer)
C. Cauda equina syndrome
D. Bilateral sciatica from disc herniation
E. Sacroiliac joint dysfunction

Explanation: ***Lumbar spinal stenosis*** - This patient presents with **neurogenic claudication**, characterized by bilateral leg pain triggered by walking and specifically relieved by **leaning forward** or sitting, which increases the spinal canal diameter. - The history of **lumbar spondylosis** is a significant risk factor, as degenerative changes like facet hypertrophy and ligamentum flavum thickening lead to canal narrowing. *Peripheral arterial disease* - Unlike neurogenic claudication, **vascular claudication** is relieved simply by standing still and does not require postural changes like leaning forward. - The presence of **palpable peripheral pulses** effectively rules out significant arterial insufficiency as the cause of the walking-induced pain. *Cauda equina syndrome* - This is a surgical emergency characterized by **saddle anesthesia**, bladder/bowel dysfunction, and significant lower limb motor weakness. - The patient has a **normal neurological examination** at rest and lacks the acute red-flag symptoms associated with this syndrome. *Bilateral sciatica from disc herniation* - Sciatica typically presents with **radicular pain** that follows a specific dermatome and is often exacerbated by coughing or a **positive straight leg raise**. - While it can be bilateral, it does not typically manifest as the specific **posture-dependent claudication** seen in spinal stenosis. *Sacroiliac joint dysfunction* - This condition usually presents with **localized buttock pain** that is unilateral and associated with specific provocative maneuvers like the **FABER test**. - It does not cause a classic claudication pattern where pain consistently begins after a set walking distance and is relieved by **spinal flexion**.

Question 182: A 75-year-old woman undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cement insertion, she suddenly becomes hypotensive (BP 75/40 mmHg), hypoxic (SpO2 88% on 15L oxygen), and loses consciousness. The anaesthetist reports sudden increase in end-tidal CO2. What is the most likely diagnosis?

A. Fat embolism syndrome
B. Acute myocardial infarction
C. Pulmonary embolism from deep vein thrombosis
D. Bone cement implantation syndrome (Correct Answer)
E. Anaphylaxis to cement

Explanation: ***Bone cement implantation syndrome***- **Bone cement implantation syndrome (BCIS)** is a life-threatening complication characterized by sudden **hypotension**, **hypoxia**, and **loss of consciousness** occurring specifically during the **cementation** phase of orthopaedic surgery.- The rise in **end-tidal CO2** (or sudden drop in some cases) and hemodynamic instability are caused by the **embolisation** of marrow fat and debris into the pulmonary circulation when cement is pressurized.*Fat embolism syndrome*- While associated with long bone fractures, this syndrome typically presents **24 to 72 hours** after the initial injury or surgery rather than acutely during cement insertion.- It is classically characterized by a clinical triad of **petechial rash**, **neurological deficit**, and respiratory distress.*Acute myocardial infarction*- Although elderly patients are at risk for **perioperative MI**, it is unlikely to be temporally linked specifically to the moment of **cement insertion**.- An MI would not typically explain the sudden increase in **pulmonary vascular resistance** and marrow emboli-related changes seen in BCIS.*Pulmonary embolism from deep vein thrombosis*- A **PE** from a pre-existing DVT usually occurs during mobilization or postoperatively rather than at the exact moment of **prosthesis implantation**.- While it causes hypoxia and hypotension, the specific surgical stage of **cementation** points more directly toward BCIS as the etiology.*Anaphylaxis to cement*- **Anaphylaxis** to methyl methacrylate is theoretically possible but extremely rare; it would usually manifest with **bronchospasm** or a **petechial/urticarial rash**.- This diagnosis does not account for the **embolic phenomenon** typically triggered by high-pressure marrow displacement during hemiarthroplasty.

Question 183: A 45-year-old man presents with a 4-week history of lower back pain and morning stiffness lasting 2 hours that improves with exercise. He reports pain in both heels and has had three episodes of acute anterior uveitis over the past 5 years. Examination reveals reduced lumbar spine flexion with a Schober's test of 3cm (normal >5cm). What is the most likely diagnosis?

A. Mechanical back pain
B. Ankylosing spondylitis (Correct Answer)
C. Lumbar disc herniation
D. Diffuse idiopathic skeletal hyperostosis
E. Reactive arthritis

Explanation: ***Ankylosing spondylitis*** - The patient presents with **inflammatory back pain**, characterized by prolonged **morning stiffness** lasting 2 hours and symptoms that **improve with exercise**. - Additional features like recurrent **acute anterior uveitis**, **heel pain** (enthesitis), and reduced lumbar spine flexion (**Schober's test** of 3cm) are classic extra-articular manifestations and signs of spinal involvement in this condition. *Mechanical back pain* - This type of back pain usually **lacks prolonged morning stiffness** and typically **worsens with activity**, improving with rest. - It does not account for systemic symptoms such as **recurrent uveitis**, **enthesitis**, or objective signs of inflammatory spinal disease like reduced lumbar flexion. *Lumbar disc herniation* - Presents primarily with acute or subacute **radicular pain** (sciatica) often with neurological deficits, rather than generalized spinal stiffness that improves with exercise. - It is not associated with **uveitis** or the inflammatory pattern of back pain described. *Diffuse idiopathic skeletal hyperostosis* - Characterized by flowing **ossification of the anterior longitudinal ligament**, commonly seen in **older patients** (often >50 years) and typically lacks inflammatory symptoms or sacroiliac joint involvement. - It does not explain the history of **recurrent acute anterior uveitis** or the inflammatory nature of the back pain. *Reactive arthritis* - While it can cause **uveitis** and **enthesitis**, it is usually an acute, self-limiting **asymmetric oligoarthritis** often triggered by a preceding infection (e.g., GI or GU). - The chronic, progressive nature of the spinal symptoms, prolonged morning stiffness, and recurrent episodes of uveitis over several years are more consistent with **Ankylosing spondylitis** rather than a typical reactive arthritis presentation.

Question 184: A 72-year-old woman with rheumatoid arthritis on long-term oral prednisolone sustains an undisplaced intracapsular neck of femur fracture. She was independently mobile with one stick pre-injury and lives alone. Her AMTS is 9/10. What is the most appropriate surgical management?

A. Cannulated hip screws
B. Dynamic hip screw
C. Total hip replacement (Correct Answer)
D. Cemented hemiarthroplasty
E. Conservative management with bed rest

Explanation: ***Total hip replacement*** - NICE guidelines recommend **total hip replacement (THR)** for patients with **intracapsular fractures** who were able to walk independently, have no cognitive impairment (**AMTS 9/10**), and are fit for the procedure. - Although the fracture is **undisplaced**, the patient's **long-term prednisolone use** and **rheumatoid arthritis** significantly increase the risk of **avascular necrosis** and **non-union** if internal fixation is attempted. *Cannulated hip screws* - These are typically used for **undisplaced intracapsular fractures** in younger or healthier patients to preserve the natural femoral head. - In this case, the **corticosteroid use** and underlying inflammatory disease make **fixation failure** and bone healing complications highly likely. *Dynamic hip screw* - This implant is the gold standard for **extracapsular intertrochanteric fractures**, not for intracapsular injuries. - It provides compression across the fracture line but is inappropriate for a patient meeting the criteria for **arthroplasty**. *Cemented hemiarthroplasty* - This is indicated for patients with **displaced** intracapsular fractures who do not meet the functional or cognitive criteria for a **THR**. - Since this patient is **cognitively intact** and **independently mobile**, a THR provides superior functional outcomes and lower rates of **acetabular erosion**. *Conservative management with bed rest* - This approach is associated with extremely high rates of **venous thromboembolism**, **pressure sores**, and **pneumonia** in the elderly. - Surgical intervention is necessary to allow for **early mobilization**, which is critical for reducing morbidity and mortality in hip fracture patients.

Question 185: A 67-year-old woman with metastatic lung cancer presents with a 3-week history of progressively worsening lower back pain that is unrelieved by lying down. She reports 8kg weight loss over the past 2 months and bilateral lower limb weakness that developed over 48 hours. On examination, there is reduced power in both legs (4/5), hyperreflexia, and sensory level at T10. What is the most urgent investigation required?

A. CT chest, abdomen and pelvis
B. MRI whole spine (Correct Answer)
C. Plain radiographs of lumbar spine
D. Bone scan
E. CT lumbar spine

Explanation: ***MRI whole spine***- The patient presents with classic signs of **Metastatic Spinal Cord Compression (MSCC)**, an oncological emergency, characterized by progressive back pain, weight loss, rapidly worsening **bilateral lower limb weakness**, **hyperreflexia**, and a distinct **sensory level at T10**.- **MRI whole spine** is the gold standard imaging modality as it precisely localizes the site(s) of spinal cord compression, provides detailed visualization of **soft tissue involvement**, and can identify **multi-level disease**, which is critical for urgent management and preventing irreversible neurological deficits.*CT chest, abdomen and pelvis*- While essential for comprehensive **cancer staging** and assessing the extent of metastatic disease, this investigation does not offer the high-resolution imaging of the **spinal cord** and surrounding epidural space required to diagnose and localize cord compression.- Prioritizing general staging over specific spinal imaging would significantly delay the diagnosis and urgent treatment needed to preserve neurological function.*Plain radiographs of lumbar spine*- Plain X-rays have very **low sensitivity** for detecting early bone metastases, especially those causing epidural compression, and cannot visualize the **spinal cord** directly.- A normal X-ray would not exclude spinal cord compression and would dangerously delay definitive neuroimaging, which is critical in this rapidly evolving clinical scenario.*Bone scan*- A bone scan is useful for identifying areas of increased **osteoblastic activity** suggestive of skeletal metastases but provides poor **anatomical resolution** of the spinal canal and spinal cord itself.- It cannot differentiate between asymptomatic bone lesions and those actively compressing the spinal cord, nor can it precisely localize the level of compression or the degree of **cord compromise**.*CT lumbar spine*- CT excels at visualizing **bony structures** and detecting fractures or lytic/blastic lesions, but it is significantly inferior to MRI for evaluating **intraspinal soft tissues**, the spinal cord, and associated edema.- Restricting the scan to the **lumbar spine** would be inappropriate given the patient's **T10 sensory level**, which strongly suggests a thoracic lesion, potentially missing the pathology entirely.

Question 186: Which anatomical classification divides neck of femur fractures based on their relationship to the hip joint capsule and the intertrochanteric line?

A. Garden classification
B. AO/OTA classification
C. Pauwels classification
D. Intracapsular versus extracapsular classification (Correct Answer)
E. Evans classification

Explanation: ***Intracapsular versus extracapsular classification*** - This classification directly addresses the relationship of **neck of femur fractures** to the **hip joint capsule** and the **intertrochanteric line**, which delineates the capsular insertion. - It is critical for prognosis as **intracapsular fractures** disrupt the crucial **retinacular blood supply** to the femoral head, increasing the risk of **avascular necrosis** and non-union. *Garden classification* - This system specifically classifies **intracapsular femoral neck fractures** based on their **degree of displacement** as seen on an anteroposterior radiograph. - It ranges from Type I (incomplete) to Type IV (fully displaced) but does not serve as the primary anatomical classification distinguishing between capsular relationships. *AO/OTA classification* - The **AO/OTA classification** is a universal, alphanumeric system used to describe **all bone fractures** based on bone location, morphology, and severity. - While it includes neck of femur fractures, it is a comprehensive system for fracture description rather than an anatomical classification based on the **hip joint capsule** itself. *Pauwels classification* - This classification categorizes femoral neck fractures based on the **angle of the fracture line** relative to the horizontal plane (Type I: <30°, Type II: 30-50°, Type III: >50°). - It primarily predicts the **biomechanical stability** and risk of shear forces at the fracture site, not its relationship to the joint capsule. *Evans classification* - The **Evans classification** is specifically used for **intertrochanteric fractures**, which are by definition **extracapsular** fractures of the proximal femur. - It focuses on the **stability** of these extracapsular fractures after reduction and fixation, rather than the initial division based on capsular relationship.

Question 187: A 54-year-old man presents with mechanical lower back pain that has persisted for 8 weeks despite conservative management. He denies any red flag symptoms. His straight leg raise test is negative bilaterally and neurological examination is normal. What is the most appropriate next step in management?

A. MRI lumbar spine
B. Urgent neurosurgical referral
C. Continuation of conservative management with physiotherapy (Correct Answer)
D. Lumbar spine radiographs
E. Commencement of oral corticosteroids

Explanation: ***Continuation of conservative management with physiotherapy*** - In the absence of **red flags** or neurological deficits, mechanical back pain is managed conservatively for at least **12 weeks** before escalated interventions are considered. - **Physiotherapy**, structured exercise programs, and appropriate analgesia are the first-line recommendations for **non-specific low back pain** to facilitate recovery and prevent chronicity. *MRI lumbar spine* - Routine **MRI imaging** is not recommended for non-specific low back pain without evidence of **radiculopathy**, neurological compromise, or suspicion of serious underlying pathology. - Imaging often reveals **incidental findings** that do not correlate with the patient's symptoms, leading to unnecessary anxiety or invasive procedures. *Urgent neurosurgical referral* - **Urgent referral** is only indicated for patients presenting with **cauda equina syndrome**, severe or progressive neurological deficits, or suspected spinal malignancy/infection. - This patient has a **normal neurological examination** and no red flags, making surgical consultation inappropriate at this stage. *Lumbar spine radiographs* - **Radiographs** provide poor soft tissue detail and lack sensitivity for most causes of chronic back pain; they are generally reserved for suspected **vertebral fractures**. - NICE guidelines state that **routine imaging** should not be offered to people with non-specific low back pain as it does not improve clinical outcomes. *Commencement of oral corticosteroids* - **Oral corticosteroids** are not a standard treatment for **mechanical back pain** and lack evidence for efficacy in this specific clinical context. - Their use is typically reserved for inflammatory conditions or specific radicular syndromes, but they carry significant **systemic side effects**.

Question 188: A 70-year-old woman is admitted following a fall. Radiographs confirm a displaced intracapsular neck of femur fracture. She is cognitively intact and was independently mobile pre-injury. Surgery is planned for the following morning. Which pre-operative investigation is most important to perform to reduce the risk of intra-operative complications?

A. Chest radiograph
B. Echocardiography
C. Group and save (Correct Answer)
D. Arterial blood gas
E. CT head

Explanation: ***Group and save*** - Surgery for **hip fractures**, particularly the arthroplasty required for displaced intracapsular fractures, carries a significant risk of **peri-operative blood loss**. - Ensuring blood is **grouped and saved** allows for rapid cross-matching and administration of blood products if hemodynamically significant **hemorrhage** occurs intra-operatively. *Chest radiograph* - While often part of a pre-operative screen, it is not routinely required unless the patient has **acute respiratory symptoms** or significant **cardiopulmonary disease**. - It does not mitigate the acute physiological risks of the surgery itself as effectively as managing potential blood loss or stability. *Echocardiography* - This investigation is not a standard requirement and is reserved for patients with severe **valvular disease** or uncompensated **heart failure**. - Routine use would cause unnecessary **surgical delays**, which the National Institute for Health and Care Excellence (NICE) advises against to avoid higher mortality. *Arterial blood gas* - This is an invasive test used for managing **complex respiratory failure** or severe acid-base disturbances, not as a standard pre-operative screen. - It provides limited utility for a stable patient without **respiratory distress** or significant chronic obstructive pulmonary disease (COPD). *CT head* - Indicated only if there is a clinical suspicion of **intracranial pathology**, such as a head injury during the fall or focal neurological deficits. - As the patient is **cognitively intact** and focused on an isolated orthopedic injury, there is no clinical justification for this imaging.

Question 189: A 64-year-old woman presents with a 2-month history of severe lower back pain, night sweats, and fever. She has poorly controlled type 2 diabetes with HbA1c of 82 mmol/mol. Examination reveals localized tenderness over L2-L3 vertebrae. Blood tests show: WCC 14.2 × 10⁹/L, CRP 156 mg/L, ESR 88 mm/hr. MRI shows L2-L3 disc space narrowing with endplate erosion and paraspinal collection. What is the definitive investigation required before initiating treatment?

A. Blood cultures
B. CT-guided biopsy of affected vertebra (Correct Answer)
C. Tuberculosis interferon-gamma release assay (IGRA)
D. Echocardiography
E. Repeat MRI with contrast in 2 weeks

Explanation: ***CT-guided biopsy of affected vertebra*** - This is the **definitive gold standard** investigation for suspected **discitis/osteomyelitis** as it provides tissue for both **histopathology** and **microbiology** to guide targeted antibiotic therapy. - Identifying the specific **causative organism** is crucial before starting long-term treatment, especially since empirical therapy may not cover resistant organisms or non-bacterial causes like tuberculosis. *Blood cultures* - While blood cultures should be performed in all suspected cases, they are only positive in approximately **30-50%** of patients with spinal infections. - Even if positive, a biopsy may still be required if the clinical response to initial treatment is poor or if a **polymicrobial infection** is suspected. *Tuberculosis interferon-gamma release assay (IGRA)* - **IGRA** can help detect latent or active **Mycobacterium tuberculosis**, but it cannot distinguish between the two or confirm the spine as the active site of infection. - A biopsy is superior as it allows for **Acid-Fast Bacilli (AFB)** staining and **Lowenstein-Jensen culture**, providing a definitive diagnosis of **Pott's disease**. *Echocardiography* - This is used to rule out **infective endocarditis**, which can seed bacteria to the spine via the **haematogenous route**, but it does not diagnose the spinal lesion itself. - It is a secondary investigation used to find the **source of bacteremia**, rather than the definitive test for the localized vertebral pathology. *Repeat MRI with contrast in 2 weeks* - Delaying diagnosis for repeat imaging is inappropriate and increases the risk of **neurological compromise** or **epidural abscess** formation. - MRI is highly sensitive for diagnosis, but **radiological changes** often lag behind clinical improvement, making frequent repeat scans unhelpful for acute management.

Question 190: A 36-year-old woman presents with a 12-week history of lower back pain, bilateral buttock pain, and morning stiffness lasting 90 minutes that improves with activity. She has a history of inflammatory bowel disease. Plain radiographs of the pelvis and lumbar spine are normal. What is the most appropriate next step in investigation?

A. HLA-B27 testing
B. MRI of sacroiliac joints (Correct Answer)
C. CT of pelvis
D. Bone density scan (DEXA)
E. Rheumatoid factor and anti-CCP antibodies

Explanation: ***MRI of sacroiliac joints*** - In patients with symptoms highly suggestive of **inflammatory back pain** and normal plain radiographs, **MRI of the sacroiliac (SI) joints** is the most sensitive test to detect early **sacroiliitis** by showing **bone marrow edema**. - This is the gold standard for diagnosing **non-radiographic axial spondyloarthritis (nr-axSpA)**, especially given the patient's history of **inflammatory bowel disease**, which is strongly associated with spondyloarthritis. *HLA-B27 testing* - While a **positive HLA-B27** allele is associated with spondyloarthropathies, it is not diagnostic on its own as it is also present in a significant portion of the **healthy population**. - A positive result can support the diagnosis but does not provide visual confirmation of **active inflammation** in the joints, which is needed for diagnosis and management. *CT of pelvis* - **CT scanning** provides excellent detail of **structural bone changes** like erosions and sclerosis, but it is less sensitive than MRI for detecting early **active inflammation** or **bone marrow edema**. - It also involves significant **ionizing radiation** exposure, making MRI a preferred and safer choice for evaluating early inflammatory changes. *Bone density scan (DEXA)* - A **DEXA scan** is used to diagnose **osteoporosis** or osteopenia by measuring bone mineral density. - It has no role in the initial diagnostic workup of **inflammatory back pain** or sacroiliitis, though patients with chronic inflammation may develop osteoporosis later. *Rheumatoid factor and anti-CCP antibodies* - These markers are specific for **rheumatoid arthritis (RA)**, which primarily involves **peripheral small joints** in a symmetrical pattern and spares the sacroiliac joints. - Axial involvement is not a feature of typical rheumatoid arthritis (except for the **C1-C2 vertebrae** in advanced disease), making these tests inappropriate for this presentation.

Question 191: A 71-year-old woman undergoes dynamic hip screw fixation for a stable intertrochanteric neck of femur fracture. What is the optimal position of the lag screw within the femoral head to reduce the risk of fixation failure?

A. Superior and anterior position
B. Inferior and posterior position
C. Central-central position with tip-apex distance <25 mm (Correct Answer)
D. Superior and posterior position
E. Inferior and anterior position

Explanation: ***Central-central position with tip-apex distance <25 mm***- The **central-central position** on both AP and lateral views ensures the lag screw is anchored in the densest **subchondral bone**, providing the greatest mechanical stability.- Maintaining a **Tip-Apex Distance (TAD)** of less than **25 mm** is the most critical surgical factor for preventing **screw cut-out**, the most common cause of fixation failure.*Superior and anterior position*- Placing the screw in a **superior position** significantly increases the risk of the screw cutting through the **superior cortex** of the femoral head under weight-bearing loads.- An **anterior position** provides thinner bone stock for the screw threads, leading to poor **purchase** and increased mechanical instability.*Inferior and posterior position*- While some surgeons traditionally favored an **inferior position** on the AP view to engage the calcar, a **posterior position** on the lateral view is associated with higher failure rates.- Deviation from the **center-center** axis in both planes increases the resultant forces that drive **fixation failure**.*Superior and posterior position*- This is considered the least desirable position as the **superior-posterior** quadrant has the lowest bone mineral density in the femoral head.- This location greatly increases the **eccentric loading** on the lag screw, predisposing the patient to early **implant cut-out**.*Inferior and anterior position*- An **anterior position** on the lateral radiograph is suboptimal because it fails to align with the **mechanical axis** of the femoral neck.- Even if the screw is **inferior** on the AP view, any eccentricity on the lateral view contributes to a higher **TAD**, surpassing the recommended **25 mm** safety threshold.

Question 192: A 49-year-old woman with a 6-month history of chronic lower back pain presents with new onset faecal incontinence and inability to feel when her bladder is full. She reports numbness in the perineal area but denies leg weakness. Lower limb examination shows normal power, normal reflexes, and intact sensation except for saddle anaesthesia. What is the most appropriate immediate management?

A. Urgent outpatient MRI within 1 week and neurology referral
B. Emergency MRI spine and surgical decompression (Correct Answer)
C. Commence gabapentin and arrange physiotherapy
D. Admit for catheterization, analgesia, and MRI within 24 hours
E. Reassure and arrange routine MRI in 4-6 weeks

Explanation: ***Emergency MRI spine and surgical decompression***- This patient presents with hallmark features of **Cauda Equina Syndrome (CES)**, including **saddle anaesthesia**, **faecal incontinence**, and loss of bladder sensation, which is a surgical emergency.- Immediate **MRI** is required to confirm the compression, followed by **urgent surgical decompression** (usually within 24-48 hours) to prevent permanent loss of bowel, bladder, and sexual function.*Urgent outpatient MRI within 1 week and neurology referral*- Any delay in imaging when CES is suspected can lead to **irreversible neurological deficits**; outpatient management is completely inappropriate for this presentation.- The management of CES is typically handled by **neurosurgery** or **orthopaedic spinal surgery**, not neurology, due to the need for mechanical decompression.*Commence gabapentin and arrange physiotherapy*- **Gabapentin** is used for chronic neuropathic pain, but it does nothing to address the **mechanical compression** of nerve roots in CES.- **Physiotherapy** is contraindicated as the primary management for an acute spinal emergency and would delay life-changing surgical intervention.*Admit for catheterization, analgesia, and MRI within 24 hours*- While the patient requires admission and catheterization, an **MRI within 24 hours** may be too slow if the goal is to optimize recovery by decompressing as soon as possible.- In the context of **sphincter disturbance** (faecal incontinence), the timeline should be emergency/immediate rather than a "within 24 hours" target which might allow for unnecessary delays.*Reassure and arrange routine MRI in 4-6 weeks*- Reassurance is dangerous in this clinical scenario as **saddle anaesthesia** and bowel/bladder dysfunction are "red flag" symptoms for spinal cord or nerve root compression.- A **routine MRI timeline** (4-6 weeks) would almost certainly guarantee the patient suffers **permanent paralysis** or permanent double incontinence.

Question 193: Which of the following arteries is most at risk during insertion of cannulated screws for fixation of an intracapsular neck of femur fracture?

A. Obturator artery
B. Medial circumflex femoral artery (Correct Answer)
C. Lateral circumflex femoral artery
D. Profunda femoris artery
E. Superior gluteal artery

Explanation: ***Medial circumflex femoral artery*** - The **medial circumflex femoral artery (MCFA)** is the most critical blood supply to the **femoral head**, particularly its posterior superior retinacular branches. Injury to these vessels is the primary cause of **avascular necrosis (AVN)** of the femoral head following intracapsular fractures. - During surgical fixation with cannulated screws, these retinacular branches, which run along the femoral neck within the capsule, are highly susceptible to direct trauma or disruption, further compromising an already precarious blood supply. *Obturator artery* - The **obturator artery** contributes a small amount to the femoral head's blood supply through the artery of the **ligamentum teres**, which is contained within the fovea capitis. - This contribution is generally considered minor and often non-functional or obliterated in adults, making it less significant for overall head viability and less at risk during screw placement in the neck. *Lateral circumflex femoral artery* - The **lateral circumflex femoral artery** primarily supplies the anterior and lateral aspects of the thigh, including the **quadriceps femoris muscles** and the anterior hip joint capsule. - While it contributes to the vascular ring around the femoral neck, its direct retinacular branches supplying the femoral head are far less significant than those of the medial circumflex femoral artery. *Profunda femoris artery* - The **profunda femoris artery**, or deep femoral artery, is a large branch of the femoral artery and gives rise to both the medial and lateral circumflex femoral arteries. - Although it is the main arterial supply to the **deep thigh musculature**, it is anatomically distant from the femoral neck itself and therefore not directly at risk during the insertion of cannulated screws. *Superior gluteal artery* - The **superior gluteal artery** is a branch of the internal iliac artery that exits the pelvis superior to the piriformis muscle, supplying the **gluteus medius**, minimus, and tensor fascia latae muscles. - This artery is located far from the femoral neck and provides no direct blood supply to the femoral head, making it safe from injury during **intracapsular cannulated screw fixation**.

Question 194: A 57-year-old man presents with a 3-month history of progressively worsening lower back pain and bilateral leg weakness. He has a 35 pack-year smoking history. Examination reveals symmetrical lower limb weakness (4/5 power), hyper-reflexia, and extensor plantar responses bilaterally. Perianal sensation is intact. What is the most likely diagnosis?

A. Cauda equina syndrome
B. Lumbar spinal stenosis
C. Thoracic cord compression (Correct Answer)
D. Peripheral neuropathy
E. Guillain-Barré syndrome

Explanation: ***Thoracic cord compression***- The presence of **upper motor neuron (UMN) signs**, such as **hyper-reflexia** and **extensor plantar responses** (Babinski sign) in the lower limbs, localizes the lesion above the level of the L1 vertebra, most commonly the thoracic spine.- The patient's 35 pack-year **smoking history** and progressive back pain raise high suspicion for **metastatic malignancy** causing spinal cord compression.*Cauda equina syndrome*- This condition involves compression of nerve roots below the spinal cord terminus, presenting with **lower motor neuron (LMN) signs**, such as **hyporeflexia** and flaccid paralysis.- It is classically associated with **saddle anesthesia** and bladder/bowel dysfunction, whereas this patient has **intact perianal sensation** and UMN signs.*Lumbar spinal stenosis*- Typically presents as **neurogenic claudication**, where leg pain and weakness are triggered by walking and relieved by leaning forward.- Physical examination generally shows **decreased or absent reflexes** (LMN signs) rather than the hyper-reflexia and extensor plantars seen here.*Peripheral neuropathy*- Characterized by a **'glove and stocking'** distribution of sensory loss and distal weakness, which does not match this patient's presentation.- Features **absent or reduced deep tendon reflexes** and is not associated with **pathological plantar responses** or back pain.*Guillain-Barré syndrome*- An acute, **ascending inflammatory polyradiculoneuropathy** that typically follows a gastrointestinal or respiratory infection.- It presents with **areflexia** and symmetric flaccid paralysis, which is inconsistent with the **spasticity and hyper-reflexia** noted in this case.

Question 195: A 79-year-old man with a displaced intracapsular neck of femur fracture is being considered for surgery. He has severe dementia (AMTS 2/10), is nursing home resident requiring full assistance with all activities of daily living, and was non-ambulatory pre-injury. What is the most appropriate surgical management?

A. Total hip replacement
B. Cemented hemiarthroplasty
C. Uncemented hemiarthroplasty
D. Internal fixation with cannulated screws
E. Conservative management with analgesia (Correct Answer)

Explanation: ***Conservative management with analgesia***- In a patient who was **non-ambulatory** pre-injury and has **severe dementia**, the surgical risks of anesthesia and post-operative complications typically outweigh the benefits of mobility restoration.- Focus shifts to **palliative care**, optimizing comfort through **pain relief**, pressure sore prevention, and maintaining quality of life rather than functional rehabilitation.*Total hip replacement*- This procedure is indicated for patients who are **active**, fit for surgery, and have no **cognitive impairment**, which is the opposite of this patient's profile.- It carries a higher risk of **dislocation** and surgical complexity that is unjustified in a non-ambulatory resident.*Cemented hemiarthroplasty*- This is the standard of care for most elderly patients with **displaced intracapsular fractures** who were previously mobile.- While it allows early weight-bearing, it is inappropriate for a patient who cannot **mobilize** due to severe pre-existing cognitive and functional deficits.*Uncemented hemiarthroplasty*- Current **NICE guidelines** generally recommend cemented over uncemented implants due to better functional outcomes and lower risk of **periprosthetic fractures**.- It offers no advantage in this specific case where the primary goal is not restoring gait in a non-ambulatory patient.*Internal fixation with cannulated screws*- This technique is generally reserved for **undisplaced fractures** or young patients where preserving the **femoral head** is a priority.- It has a high **failure rate** in displaced fractures in the elderly and would subject this frail patient to an unnecessary surgical intervention.

Question 196: A 42-year-old woman presents with a 4-week history of lower back pain and morning stiffness lasting 2 hours. She reports improvement with exercise. She has a history of psoriasis and recurrent anterior uveitis. Inflammatory markers are elevated: CRP 34 mg/L, ESR 42 mm/hr. What is the most appropriate initial imaging investigation?

A. Plain radiographs of lumbar spine and sacroiliac joints
B. MRI of the lumbar spine
C. MRI of sacroiliac joints (Correct Answer)
D. CT of the lumbar spine
E. Bone scan

Explanation: ***MRI of sacroiliac joints*** - Given the patient's **inflammatory back pain** (morning stiffness, improvement with exercise), history of **psoriasis**, and **uveitis**, **axial spondyloarthropathy** is highly suspected. - **MRI of the sacroiliac joints** is the most sensitive imaging modality for detecting **early active sacroiliitis** (bone marrow edema), which is crucial for diagnosis in the initial stages when X-rays may still be normal. *Plain radiographs of lumbar spine and sacroiliac joints* - **Plain radiographs** primarily detect **chronic structural damage** such as erosions, sclerosis, or ankylosis, which may take years to develop and might not be present in early disease. - In the context of **early inflammatory back pain** and suspicion of axial spondyloarthropathy, X-rays have **low sensitivity** for active inflammation and can lead to delayed diagnosis. *MRI of the lumbar spine* - While an **MRI of the lumbar spine** can identify spinal pathology, it may not adequately visualize the **sacroiliac joints**, which are typically the primary site of inflammation in axial spondyloarthropathy. - It focuses more on **vertebral bodies**, **intervertebral discs**, and **spinal cord structures**, which are less likely to show the earliest inflammatory changes specific to this condition. *CT of the lumbar spine* - **CT scans** excel at visualizing **bony architecture** and detecting structural changes like erosions or fusion but are **less sensitive than MRI** for detecting early active inflammation (bone marrow edema). - It also involves significant **ionizing radiation**, making it a less suitable initial diagnostic choice compared to MRI for suspected inflammatory conditions. *Bone scan* - A **bone scan** (scintigraphy) is highly sensitive for detecting increased metabolic activity but has **low specificity**, meaning it cannot differentiate well between inflammatory, degenerative, or traumatic causes of bone uptake. - It is generally **not recommended** as a primary diagnostic tool for early axial spondyloarthropathy due to its lack of detail and inability to precisely localize or characterize the type of inflammation.

Question 197: A 68-year-old man undergoes hemiarthroplasty for a displaced intracapsular neck of femur fracture. On day 2 post-operatively, he develops acute confusion, tachycardia (125 bpm), tachypnoea (28/min), temperature 38.2°C, and petechial rash over the anterior chest. Oxygen saturation is 91% on room air. What is the most likely diagnosis?

A. Fat embolism syndrome (Correct Answer)
B. Septic arthritis
C. Hospital-acquired pneumonia
D. Deep vein thrombosis with pulmonary embolism
E. Post-operative delirium

Explanation: ***Fat embolism syndrome***- This patient exhibits the classic clinical triad of **respiratory distress** (tachypnoea, hypoxia), **neurological dysfunction** (acute confusion), and a **petechial rash** over the anterior chest, which is pathognomonic for this syndrome.- It typically occurs **24-72 hours** after long bone or pelvic fractures, or orthopedic procedures like **hemiarthroplasty**, due to the release of fat globules into the circulation.*Septic arthritis*- This usually presents as a **localized infection** of a joint characterized by severe pain, swelling, and **restricted range of motion**, rather than systemic respiratory and skin findings.- While it can cause fever, it would not explain the sudden onset **hypoxia** or the presence of a **petechial rash** on the chest.*Hospital-acquired pneumonia*- Pneumonia could explain the fever and **tachypnoea**, but it is generally associated with productive cough and **bronchial breath sounds** on auscultation.- It does not account for the **acute confusion** or the highly specific **petechial rash**, which is a key indicator for fat embolism in this context.*Deep vein thrombosis with pulmonary embolism*- **Pulmonary embolism (PE)** is a major cause of post-operative hypoxia, tachycardia, and tachypnoea, but it typically lacks the prominent **neurological symptoms** and the **petechial rash** seen here.- While both conditions can cause respiratory distress, the rapid onset of confusion and skin findings strongly favors fat embolism syndrome over a standard thromboembolism.*Post-operative delirium*- Delirium is common in elderly post-operative patients but is primarily a diagnosis of exclusion that does not account for the specific **physiological instability** like fever, marked hypoxia, or tachycardia.- It would never be associated with a **petechial rash**, which indicates a more complex systemic pathological process than isolated brain dysfunction.

Question 198: Which nerve root is most commonly affected in lumbar disc herniation causing sciatica with loss of ankle reflex?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - The **ankle reflex** (Achilles tendon reflex) is primarily mediated by the **S1 nerve root**; therefore, its loss is a hallmark of S1 radiculopathy. - S1 nerve root compression, often due to an **L5-S1 disc herniation**, typically results in sensory loss at the **lateral foot** and weakness in **plantar flexion**. *L3* - Injury to the L3 nerve root affects the **patellar (knee) reflex**, not the ankle reflex. - L3 radiculopathy usually presents with pain and sensory loss over the **anterior thigh** and weakness in **hip adduction**. *L4* - The L4 nerve root is the main mediator of the **patellar reflex**, and its compression leads to a diminished knee-jerk response. - It is associated with **weakness in knee extension** (quadriceps) and sensory loss over the **medial malleolus**. *L5* - L5 radiculopathy characteristically causes **weakness in big toe extension** (Extensor Hallucis Longus) and **foot drop** during dorsiflexion. - Crucially, the **ankle reflex remains intact** in L5 lesions because the reflex arc is specifically dependent on the S1 root. *S2* - S2 nerve root involvement is rare in isolated lumbar disc herniations and primarily contributes to **bladder and bowel function** or sensation in the **perineal area**. - While it contributes slightly to the Achilles reflex, its isolation would not be the primary cause of a completely lost ankle reflex, which is distinct from the primary S1 involvement.

Question 199: A 73-year-old woman sustains a reverse oblique intertrochanteric femur fracture following a fall. She is medically optimized and undergoes surgical fixation. Which fixation method is most appropriate for this fracture pattern?

A. Dynamic hip screw with plate
B. Cannulated screws
C. Cephalomedullary nail (Correct Answer)
D. Total hip replacement
E. Hemiarthroplasty

Explanation: ***Cephalomedullary nail*** - For **reverse oblique intertrochanteric fractures**, cephalomedullary nails provide superior **biomechanical stability** by acting as a buttress to prevent **medial displacement** of the femoral shaft. - This intramedullary device is less likely to fail under the high mechanical stress associated with this specific **unstable fracture pattern** compared to extramedullary implants. *Dynamic hip screw with plate* - A **DHS** is biomechanically unsuitable here because the fracture line runs from **superomedial to inferolateral**, which allows the femoral shaft to slide medially along the screw. - Use of a side plate in reverse oblique patterns often leads to **fixation failure** and nonunion due to the lack of an intact lateral wall to provide support. *Cannulated screws* - These are primarily indicated for **nondisplaced intracapsular femoral neck fractures**, not extracapsular intertrochanteric fractures. - They lack the necessary **load-bearing strength** to stabilize complex, high-energy, or unstable intertrochanteric fracture lines. *Total hip replacement* - **Total hip arthroplasty** is generally reserved for **intracapsular fractures**, severe hip osteoarthritis, or salvage after failed internal fixation. - It is overly invasive for an isolated intertrochanteric fracture where the **femoral head and acetabulum** are otherwise healthy. *Hemiarthroplasty* - This procedure is typically used for **displaced femoral neck fractures** in elderly patients to allow early mobilization, not as a primary treatment for reverse oblique patterns. - Fixation with a nail is preferred over hemiarthroplasty to **preserve the native joint** and avoid the higher risks of dislocation associated with arthroplasty in extracapsular fractures.

Question 200: A 34-year-old man presents to the Emergency Department with a 48-hour history of severe lower back pain radiating to both legs, urinary retention, and saddle anaesthesia. He reports difficulty walking and bilateral foot drop. Examination confirms reduced anal tone. What is the most appropriate immediate management?

A. Urgent MRI spine and neurosurgical referral for decompression within 48 hours
B. Commence high-dose oral prednisolone and arrange outpatient MRI
C. Admit for bed rest, analgesia, and physiotherapy assessment
D. Emergency MRI spine and surgical decompression within 6 hours (Correct Answer)
E. CT spine and commence intravenous antibiotics

Explanation: ***Emergency MRI spine and surgical decompression within 6 hours*** - This patient presents with classic **Cauda Equina Syndrome (CES)**, characterized by **saddle anesthesia**, **urinary retention**, **bilateral foot drop**, and **reduced anal tone**, which constitutes a neurosurgical emergency. - **Emergency MRI** is crucial for confirming the diagnosis and localizing the compression. **Surgical decompression** must be performed as soon as possible, ideally within **6-24 hours**, to maximize the chances of neurological recovery and prevent permanent deficits. *Urgent MRI spine and neurosurgical referral for decompression within 48 hours* - While an **urgent MRI** and **decompression** are indicated, the 48-hour timeframe is too long given the acute and severe neurological deficits, including **urinary retention** and **bilateral foot drop**. - Delaying surgery beyond the critical window significantly increases the risk of irreversible neurological damage, especially to bladder and bowel function. *Commence high-dose oral prednisolone and arrange outpatient MRI* - **High-dose prednisolone** is typically reserved for **spinal cord compression** due to malignancy or inflammatory conditions, not for mechanical compression in CES. - An **outpatient MRI** is dangerously inappropriate for a suspected **neurosurgical emergency** like CES, which requires immediate diagnostic imaging and intervention. *Admit for bed rest, analgesia, and physiotherapy assessment* - This approach constitutes **conservative management**, which is suitable for uncomplicated mechanical back pain without neurological compromise. - It is completely inadequate for **Cauda Equina Syndrome**, where progressive neurological deficits and permanent disability are imminent without urgent surgical intervention. *CT spine and commence intravenous antibiotics* - **CT spine** has limitations in visualizing soft tissue structures like herniated discs, making **MRI** the superior imaging modality for CES. - **Intravenous antibiotics** are not indicated as there is no mention or clinical suspicion of an infectious cause, such as an **epidural abscess**.

Question 201: What is the primary mechanism by which weight-bearing status is restricted following internal fixation of an undisplaced intracapsular neck of femur fracture with cannulated screws?

A. To prevent avascular necrosis of the femoral head
B. To allow bone healing and prevent fracture displacement (Correct Answer)
C. To reduce the risk of deep vein thrombosis
D. To minimize pain during the early post-operative period
E. To prevent failure of the fixation implant

Explanation: ***To allow bone healing and prevent fracture displacement*** - Restricting weight-bearing is crucial to maintain the **anatomical alignment** of an undisplaced fracture while the **primary bone healing** occurs. - Premature excessive loading can lead to **secondary displacement** of the intracapsular fracture, which significantly increases the risk of fixation failure and the need for **arthroplasty**. *To prevent avascular necrosis of the femoral head* - **Avascular necrosis (AVN)** is primarily caused by the initial **vascular insult** to the retinacular vessels during the injury itself. - While weight-bearing is restricted post-surgery, it does not directly prevent the biological process of **ischemic necrosis** resulting from interrupted blood supply. *To reduce the risk of deep vein thrombosis* - Weight-bearing restriction actually **increases** the risk of venous stasis and **deep vein thrombosis (DVT)** rather than reducing it. - DVT prevention is achieved through **pharmacological prophylaxis** and encouraging early **ankle pump exercises** and mobilization within safe limits. *To minimize pain during the early post-operative period* - While limiting movement may indirectly help with comfort, **pain management** is primarily addressed with **analgesics** and regional nerve blocks. - Clinical protocols for weight-bearing are based on **fracture stability** and biomechanics rather than purely on the patient's pain threshold. *To prevent failure of the fixation implant* - Although implant protection is important, **titanium or steel cannulated screws** are designed to withstand significant stress; the weaker link is the **bone-screw interface**. - The primary focus is preventing the **bone fragments** from shifting (displacement) rather than worrying about the structural breakage of the **metal hardware** itself.

Question 202: A 63-year-old man presents with a 5-month history of lower back pain and weight loss of 8 kg. He has a history of prostate cancer treated with radical prostatectomy 3 years ago. Examination reveals tenderness over L3 vertebra. His PSA is 45 ng/mL (previous baseline <0.1 ng/mL). Plain radiographs show a sclerotic lesion at L3. What is the most appropriate next investigation?

A. MRI spine with gadolinium contrast (Correct Answer)
B. CT-guided biopsy of L3 lesion
C. Bone scan
D. PET-CT scan
E. CT abdomen and pelvis

Explanation: ***MRI spine with gadolinium contrast*** - Given the patient's history of **prostate cancer**, rising **PSA**, back pain, weight loss, and a **sclerotic lesion** at L3, there is a high suspicion of **spinal metastasis**. - **MRI with gadolinium contrast** is the gold standard for evaluating **spinal cord compression** or **nerve root impingement**, which are critical to assess immediately to prevent irreversible neurological damage due to excellent **soft tissue resolution** and assessment of **epidural disease**. *CT-guided biopsy of L3 lesion* - While biopsy provides **histological confirmation**, it is generally not the most appropriate *next* step when the primary cancer is known (prostate) and there is clear evidence of **biochemical recurrence** and a suspected metastatic lesion. - The immediate priority is to assess for **spinal cord compression**, which a biopsy does not achieve and could delay crucial imaging. *Bone scan* - A **bone scan** (Technetium-99m) is highly sensitive for detecting **osteoblastic metastases** across the skeleton and identifying additional sites of disease. - However, it lacks the anatomical detail to assess the **spinal canal** and cannot accurately rule out or characterize **spinal cord compression**, which is the most dangerous complication in this scenario. *PET-CT scan* - **PET-CT** (e.g., FDG-PET or PSMA-PET for prostate cancer) is valuable for systemic staging and assessing metabolic activity of tumors. - Nevertheless, it does not offer the same **soft tissue resolution** as MRI for detailed evaluation of the **spinal cord** and **epidural space** to accurately assess for **cord compression**. *CT abdomen and pelvis* - This imaging is useful for identifying **visceral metastases** or **lymphadenopathy** and can further characterize bony lesions. - However, it provides insufficient detail of the **spinal cord** and **nerve roots** to accurately assess for **spinal cord compression**, which is the most urgent concern with localized back pain and a spinal lesion.

Question 203: A 77-year-old woman undergoes surgical fixation of a subcapital neck of femur fracture. Post-operatively, she develops sudden onset shortness of breath, hypoxia and hypotension within 30 minutes of cement insertion. Her oxygen saturation is 88% on room air, blood pressure 85/50 mmHg, and heart rate 115 bpm. What is the most likely diagnosis?

A. Fat embolism syndrome
B. Bone cement implantation syndrome (Correct Answer)
C. Pulmonary embolism
D. Myocardial infarction
E. Anaphylactic reaction

Explanation: ***Bone cement implantation syndrome*** - This clinical picture of sudden **hypoxia**, **hypotension**, and **tachycardia** occurring specifically within minutes of **cement insertion** is classic for bone cement implantation syndrome (BCIS). - It is caused by the **embolization** of bone marrow, fat, and cement monomers into the **pulmonary circulation**, leading to acute right heart strain and cardiopulmonary collapse. *Fat embolism syndrome* - Typically presents **24-72 hours** after a long bone or pelvic fracture, not within minutes of a surgical procedure involving cement. - Characterized by a classic triad of **respiratory distress**, **neurological symptoms**, and a **petechial rash**, which is missing in this immediate presentation. *Pulmonary embolism* - While it causes acute hypoxia and hypotension, it usually occurs hours to several days post-operatively due to **deep vein thrombosis** rather than intra-operatively. - The immediate temporal relationship with the use of **methyl methacrylate (cement)** specifically points toward BCIS over standard thromboembolism. *Myocardial infarction* - Post-operative MI could present with hypotension and tachycardia, but **acute hypoxia** as the primary sudden feature is less typical without pulmonary edema. - Unlike BCIS, an MI is not directly triggered by the specific act of **pressurizing cement** within the femoral canal. *Anaphylactic reaction* - Anaphylaxis often features cutaneous signs like **urticaria** or **angioedema** and respiratory signs like **bronchospasm** (wheeze). - While cement could theoretically cause an allergy, the hemodynamic collapse associated with bone cement is almost always due to **embolic phenomena** and pulmonary hypertension rather than IgE-mediated allergy.

Question 204: A 51-year-old woman presents to her GP with a 10-week history of lower back pain. She has a history of breast cancer treated with mastectomy and chemotherapy 3 years ago and has been disease-free since. The pain has gradually worsened and is now present at night, interfering with sleep. She has no leg symptoms or neurological deficit. Examination reveals tenderness over T12 and L1 vertebrae. What is the single most important next step in management?

A. Arrange urgent MRI spine within 1 week (Correct Answer)
B. Prescribe NSAIDs and arrange routine physiotherapy
C. Request urgent whole body bone scan
D. Arrange plain radiographs of thoracolumbar spine
E. Refer urgently to orthopaedic clinic

Explanation: ***Arrange urgent MRI spine within 1 week*** - This patient's history of **breast cancer**, new progressive and **nocturnal back pain**, and focal **vertebral tenderness** are significant **red flags** for spinal metastases. - An **urgent MRI spine** is the most sensitive and specific investigation to detect **spinal cord compression** or **metastatic disease** affecting the vertebrae and soft tissues, even in the absence of neurological deficits. *Prescribe NSAIDs and arrange routine physiotherapy* - Prescribing NSAIDs and physiotherapy is inappropriate given the **red flags** indicating a high suspicion of **malignancy** or **spinal cord compression**. - Delaying definitive diagnosis and treatment could lead to serious, potentially **irreversible neurological damage**. *Request urgent whole body bone scan* - While a bone scan is sensitive for many metastases, it has limitations, particularly for **osteolytic lesions** common in breast cancer, and provides poor anatomical detail of the spinal canal. - A **bone scan** cannot accurately assess for **epidural extension** of tumor or **thecal sac compression**, which are critical for guiding immediate management decisions. *Arrange plain radiographs of thoracolumbar spine* - **Plain radiographs** have very low sensitivity for detecting early metastatic disease; typically, **30-50% bone destruction** is required before a lesion becomes visible. - X-rays cannot visualize **soft tissue involvement**, **spinal cord compression**, or the extent of tumor within the spinal canal. *Refer urgently to orthopaedic clinic* - While a referral to orthopaedics may be necessary, the single most important immediate step is to obtain **urgent imaging** (MRI). - The specific findings on the **MRI** will determine the urgency and nature of the orthopaedic intervention required, or guide referral to other specialties like oncology.

Question 205: A 77-year-old woman presents following a fall. Radiographs confirm a displaced intracapsular neck of femur fracture. She lives alone, mobilises independently with a stick, and has mild Alzheimer's disease but manages her own activities of daily living with minimal support. Her AMTS is 7/10. She has no significant past medical history. Which surgical option is most appropriate?

A. Total hip replacement (Correct Answer)
B. Cemented hemiarthroplasty
C. Uncemented hemiarthroplasty
D. Internal fixation with cannulated screws
E. Dynamic hip screw

Explanation: ***Total hip replacement*** - **NICE guidelines** recommend total hip replacement (THR) for patients with **displaced intracapsular** fractures who can walk independently outdoors with no more than a **one-stick gait** and are not severely cognitively impaired. - Her **AMTS of 7/10** (mild impairment) and ability to perform **activities of daily living (ADLs)** independently make her suitable for THR, which offers superior long-term functional outcomes for active individuals. *Cemented hemiarthroplasty* - This is generally reserved for patients with displaced intracapsular fractures who have **significant cognitive impairment** or limited preoperative mobility. - For a high-functioning patient who **mobilises independently** with a stick, THR is preferred over hemiarthroplasty for better long-term functional results. *Uncemented hemiarthroplasty* - **Uncemented prostheses** are generally avoided in hip fractures in the elderly due to a higher risk of **periprosthetic fractures** and increased postoperative thigh pain. - Current standards (e.g., **NICE guidelines**) strongly favor **cemented fixation** to ensure better stability and reduced pain in the elderly population. *Internal fixation with cannulated screws* - This approach is typically reserved for **undisplaced (Garden I and II)** intracapsular fractures to preserve the native femoral head. - Using this for a **displaced fracture** in a 77-year-old carries a high risk of **avascular necrosis (AVN)** and non-union, leading to poor outcomes. *Dynamic hip screw* - A dynamic hip screw (DHS) is the gold standard treatment for **extracapsular (intertrochanteric)** hip fractures, which are outside the joint capsule. - It is unsuitable for an **intracapsular fracture** as it does not address the primary concern of **disrupted blood supply** to the femoral head.

Question 206: A 33-year-old man who works in construction presents with a 2-week history of severe lower back pain radiating down his right leg. He describes paraesthesia over the dorsum of his right foot and difficulty walking on his heels. He has no bladder or bowel symptoms. Examination reveals 4/5 power in right ankle dorsiflexion, reduced sensation in the L5 dermatome, and positive right-sided straight leg raise at 40 degrees. What is the most appropriate initial management?

A. Urgent MRI and neurosurgical referral
B. Oral analgesia, advice to remain active, and review in 6 weeks (Correct Answer)
C. Immediate bed rest for 2 weeks
D. Oral prednisolone 40mg for 5 days
E. Urgent nerve conduction studies

Explanation: ***Oral analgesia, advice to remain active, and review in 6 weeks*** - In the absence of **red flags** (such as cauda equina symptoms) or severe/progressive neurological deficits (the patient has 4/5 power, not complete paralysis), initial management of **sciatica** or **radiculopathy** is conservative. - This approach involves **pain management** (oral analgesia), encouraging the patient to **remain active**, and allowing sufficient time (typically up to 6-12 weeks) for the **herniated disc** to naturally resorb and symptoms to improve. *Urgent MRI and neurosurgical referral* - This intervention is reserved for **red flag** conditions like **cauda equina syndrome** (not present here as there are no bladder/bowel symptoms), significant or **progressive motor weakness** (e.g., foot drop 0/5), or suspected malignancy/infection. - An MRI is generally not indicated in acute radiculopathy lasting less than 6 weeks without these concerning features, as it rarely changes initial conservative management. *Immediate bed rest for 2 weeks* - **Bed rest** is **contraindicated** for acute low back pain and radiculopathy, as it can worsen symptoms, delay recovery, and lead to deconditioning. - Patients are strongly advised to **stay active** and continue with daily activities as tolerated to promote recovery and prevent chronicity. *Oral prednisolone 40mg for 5 days* - **Systemic corticosteroids** generally do not have strong evidence to support their routine use in acute disc herniation or radiculopathy for improving long-term outcomes. - While they might provide short-term pain relief, the risks often outweigh the benefits, and management focuses on non-steroidal anti-inflammatory drugs (**NSAIDs**) and other analgesics. *Urgent nerve conduction studies* - **Nerve conduction studies (NCS)** are not typically indicated in the acute phase of radiculopathy as a first-line diagnostic or management tool. - They are primarily useful in more chronic cases or when differentiating between **radiculopathy** and **peripheral neuropathy**, or for surgical planning after conservative treatment failure.

Question 207: A 68-year-old man undergoes total hip replacement for a displaced intracapsular neck of femur fracture. He has a past medical history of chronic kidney disease stage 4, ischaemic heart disease, and previous hip osteoarthritis. Post-operatively on day 2, he develops acute confusion and becomes agitated. His observations show: temperature 38.2°C, heart rate 105 bpm, blood pressure 95/60 mmHg, respiratory rate 24/min, oxygen saturation 91% on room air. Chest examination reveals bronchial breathing in the right lower zone. What is the most appropriate initial management?

A. Administer intravenous antibiotics after blood cultures (Correct Answer)
B. Arrange urgent CT pulmonary angiogram
C. Commence subcutaneous low molecular weight heparin
D. Administer intravenous fluids and haloperidol
E. Arrange urgent echocardiogram

Explanation: ***Administer intravenous antibiotics after blood cultures*** - The patient's presentation with **fever**, **hypotension**, **tachycardia**, **tachypnoea**, acute **confusion**, and **bronchial breathing** in the right lower zone strongly indicates **sepsis** secondary to **post-operative pneumonia**. - Following the **Sepsis Six** bundle, urgent administration of **broad-spectrum intravenous antibiotics** after obtaining **blood cultures** is the most critical initial management step to treat the life-threatening infection. *Arrange urgent CT pulmonary angiogram* - While **pulmonary embolism** is a differential in post-operative patients, the presence of **fever** and localized **bronchial breathing** points more strongly towards **pneumonia**. - An **urgent CTPA** would expose a patient with **stage 4 chronic kidney disease** to **nephrotoxic intravenous contrast**, carrying a significant risk of **contrast-induced nephropathy**. *Commence subcutaneous low molecular weight heparin* - **Low molecular weight heparin** is primarily used for **venous thromboembolism prophylaxis** or therapeutic treatment, which is not the immediate priority for a patient in **septic shock** with **pneumonia**. - Addressing the acute infection and hemodynamic instability takes precedence over starting anticoagulation in this critically unwell patient. *Administer intravenous fluids and haloperidol* - While **intravenous fluids** are a component of **sepsis resuscitation**, the definitive initial management for the underlying infection is **antibiotic therapy**. - Administering **haloperidol** for agitation before treating the underlying cause, likely **sepsis-induced delirium**, is inappropriate and can mask worsening clinical signs, delaying crucial treatment. *Arrange urgent echocardiogram* - An **echocardiogram** evaluates cardiac function and could be considered for a patient with a history of **ischaemic heart disease**, but it is not the primary diagnostic tool for **pneumonia** or the most urgent initial step in this septic patient. - The acute respiratory signs and fever point towards an infectious etiology, making the echocardiogram a less immediate priority compared to managing **sepsis** and **pneumonia**.

Question 208: A 39-year-old woman presents with a 3-month history of lower back pain and stiffness. She works as a nurse and attributes the pain to her job. The pain is present throughout the day and worsens in the evenings after work. She sleeps well at night. Morning stiffness lasts approximately 10 minutes. Examination shows normal lumbar spine flexion and no neurological deficit. Blood tests including FBC, ESR, and CRP are normal. What is the most likely diagnosis?

A. Mechanical back pain (Correct Answer)
B. Ankylosing spondylitis
C. Spinal infection
D. Malignancy
E. Inflammatory bowel disease-associated arthropathy

Explanation: ***Mechanical back pain***- The pain **worsens with activity** in the evening and improves with rest at night, which is the classic presentation of **mechanical strain** rather than inflammation.- **Morning stiffness** lasting only 10 minutes and **normal inflammatory markers** (ESR/CRP) strongly support a mechanical etiology over systematic diseases.*Ankylosing spondylitis*- This condition typically presents with stiffness that **improves with exercise** and is most severe in the early morning, lasting longer than **30 minutes**.- It often leads to **nocturnal pain** that wakes the patient up, whereas this patient **sleeps well at night**.*Spinal infection*- Characterized by **systemic features** like fever, night sweats, and localized severe spinal tenderness, which are absent here.- Laboratory investigations would typically reveal **elevated ESR and CRP**, but this patient's results are normal.*Malignancy*- Usually presents in older patients with **red flag symptoms** such as unexplained weight loss, night pain, and a history of cancer.- Chronic back pain from malignancy is often **progressive and non-mechanical**, meaning it does not resolve with rest.*Inflammatory bowel disease-associated arthropathy*- Typically involves **extraintestinal manifestations** such as diarrhea, abdominal pain, or blood in the stool.- It follows an **inflammatory pattern** of back pain similar to ankylosing spondylitis, which is inconsistent with this patient's activity-related pain.

Question 209: A 66-year-old woman sustains a minimally displaced intracapsular neck of femur fracture (Garden II). She is cognitively intact, lives independently, and was walking without aids prior to the injury. Her medical history includes well-controlled type 2 diabetes and hypertension. She undergoes internal fixation with cannulated screws. At 6-month follow-up, she reports increasing hip pain over the past month. Radiographs show increased density of the femoral head with no evidence of fracture healing. What is the most likely diagnosis?

A. Non-union
B. Avascular necrosis (Correct Answer)
C. Deep infection
D. Screw loosening
E. Osteoarthritis

Explanation: ***Avascular necrosis*** - Intracapsular femoral neck fractures inherently compromise the blood supply to the femoral head, primarily via the **medial circumflex femoral artery**, predisposing to **avascular necrosis (AVN)**. - The radiographic finding of **increased density (sclerosis)** of the femoral head, along with increasing pain and lack of fracture healing 6 months post-surgery, is characteristic of AVN. *Non-union* - While pain and lack of healing are present, non-union typically presents with a **persistent fracture line** and either atrophic or hypertrophic changes at the fracture site itself. - The specific finding of diffuse **increased density of the femoral head** points more definitively to AVN rather than isolated non-union. *Deep infection* - Deep infection would typically involve **systemic symptoms** such as fever, malaise, and elevated inflammatory markers (ESR, CRP), none of which are mentioned in the case. - Radiographically, infection might show signs of **osteolysis**, periosteal reaction, or bone destruction, rather than the described uniform increased density of the femoral head. *Screw loosening* - Screw loosening is usually evidenced by **radiolucent halos** around the implant on radiographs, indicating bone resorption around the screws. - While it can cause pain and be associated with non-union, it does not account for the specific and prominent finding of **increased density of the femoral head**. *Osteoarthritis* - Although AVN can eventually lead to secondary osteoarthritis, direct post-traumatic **osteoarthritis** typically takes longer than six months to develop with hallmark features like **joint space narrowing** and osteophyte formation. - The primary finding of **increased density of the femoral head** points to the underlying ischemic process (AVN) as the immediate and most likely diagnosis.

Question 210: A 47-year-old warehouse worker presents with a 5-week history of lower back pain radiating to both buttocks and posterior thighs. He describes numbness in the perineal area and has noticed difficulty initiating urination over the past 48 hours. On examination, there is reduced anal tone. His vital signs are: temperature 36.8°C, heart rate 78 bpm, blood pressure 135/82 mmHg. What is the most appropriate immediate management?

A. Urgent MRI spine and neurosurgical referral (Correct Answer)
B. Prescribe oral analgesia and physiotherapy referral
C. Arrange outpatient MRI within 2 weeks
D. Commence oral prednisolone
E. Perform lumbar puncture

Explanation: ***Urgent MRI spine and neurosurgical referral*** - The patient's presentation with **perineal numbness (saddle anesthesia)**, **difficulty initiating urination (urinary retention)**, and **reduced anal tone** are classic red flag symptoms indicating **cauda equina syndrome (CES)**. - **Immediate MRI of the spine** is essential to confirm the diagnosis and identify the level of compression, followed by an **urgent neurosurgical referral** for potential emergent decompression to prevent permanent neurological deficits. *Prescribe oral analgesia and physiotherapy referral* - This approach is suitable for **uncomplicated, non-specific lower back pain** without signs of severe neurological compromise. - Providing only conservative management for suspected **cauda equina syndrome** would dangerously delay definitive treatment and risk irreversible **bladder, bowel, and sexual dysfunction**. *Arrange outpatient MRI within 2 weeks* - An **outpatient MRI** with a several-week waiting period is appropriate for less urgent conditions, such as persistent radiculopathy or suspected but stable spinal pathology. - In suspected **cauda equina syndrome**, imaging must be performed **urgently (within hours)** because delaying diagnosis and treatment can lead to permanent nerve damage. *Commence oral prednisolone* - While **corticosteroids** might be considered in some cases of spinal cord compression due to inflammatory processes or malignancy, they are generally not the primary treatment for mechanical compression like a **disc herniation** causing CES. - The definitive management for mechanical **cauda equina syndrome** is **surgical decompression**, not medical management with steroids. *Perform lumbar puncture* - **Lumbar puncture** is primarily indicated for diagnosing infections (e.g., meningitis), inflammatory conditions, or subarachnoid hemorrhage affecting the cerebrospinal fluid. - It has no role in the diagnosis of **cauda equina syndrome** caused by mechanical compression and would not provide information about the structural cause of the patient's symptoms.

Question 211: Which of the following is the primary blood supply to the femoral head that is most at risk during an intracapsular neck of femur fracture?

A. Medial circumflex femoral artery via retinacular vessels (Correct Answer)
B. Lateral circumflex femoral artery
C. Artery of ligamentum teres
D. Superior gluteal artery
E. Obturator artery

Explanation: ***Medial circumflex femoral artery via retinacular vessels*** - This artery provides roughly **70-80% of the blood supply** to the adult femoral head, primarily via the **lateral epiphyseal vessels**. - Because these vessels travel along the femoral neck within the joint capsule, an **intracapsular fracture** often disrupts them, leading to a high risk of **avascular necrosis**. *Lateral circumflex femoral artery* - This artery contributes primarily to the blood supply of the **inferior and anterior** portions of the femoral neck and the **greater trochanter**. - While it participates in the extracapsular arterial ring, its contribution to the actual **femoral head perfusion** is significantly less than that of the medial circumflex. *Artery of ligamentum teres* - This vessel is a branch of the **obturator artery** (or Medial Circumflex) and provides a significant portion of blood supply during **childhood**. - In adults, it is often obliterated or provides only **minimal supply** to a small area surrounding the fovea capitis, making it insufficient to prevent necrosis if retinacular vessels are torn. *Superior gluteal artery* - The primary role of this artery is to supply the **gluteus medius, gluteus minimus**, and tensor fasciae latae muscles. - It does not provide any direct or significant blood supply to the **femoral head**. *Obturator artery* - It gives rise to the **artery of the ligamentum teres**, but it is not the dominant source of blood for the femoral head in the adult population. - Its primary function involves supplying the **adductor muscles** of the thigh and the skin of the medial thigh area.

Question 212: A 75-year-old woman undergoes dynamic hip screw fixation for an intertrochanteric femoral fracture. Post-operatively, the tip-apex distance is measured at 32 mm on the anteroposterior and lateral radiographs. What is the significance of this measurement?

A. This is optimal and associated with low risk of screw cut-out
B. This is acceptable but monitoring is required
C. This indicates increased risk of screw cut-out and revision may be needed (Correct Answer)
D. This measurement only applies to cannulated screw fixation
E. This indicates the screw is too short

Explanation: ***This indicates increased risk of screw cut-out and revision may be needed*** - The **Tip-Apex Distance (TAD)** is a critical predictor of mechanical failure in proximal femoral fracture fixation, with a measurement **>25 mm** strongly correlating with an increased risk of **screw cut-out**. - A TAD of 32 mm is significantly above the safe threshold, indicating **suboptimal screw placement** and a high likelihood of fixation failure, potentially requiring **revision surgery**. *This is optimal and associated with low risk of screw cut-out* - This statement is incorrect; an **optimal TAD** for dynamic hip screws should be **less than 25 mm** to ensure stable fixation and minimize complications. - A TAD of 32 mm signifies a **poor prognosis** and a significantly elevated risk of the implant migrating out of the femoral head. *This is acceptable but monitoring is required* - A TAD of 32 mm is not considered **acceptable** in orthopedic practice due to the clear evidence linking higher TAD values to **fixation failure**. - While monitoring is always part of post-operative care, this measurement points to a **specific mechanical risk** that often warrants more than just observation. *This measurement only applies to cannulated screw fixation* - The **Tip-Apex Distance (TAD)** was specifically introduced by **Baumgaertner** and is primarily used for **extracapsular femoral fractures** fixed with devices like **dynamic hip screws** or cephalomedullary nails. - It is less commonly applied to **cannulated screw fixation** for intracapsular femoral neck fractures, where different stability metrics are often used. *This indicates the screw is too short* - A high TAD often suggests either the screw is **too short** or, more importantly, **malpositioned** within the femoral head (e.g., placed eccentrically). - The TAD specifically measures the distance from the screw tip to the apex of the femoral head on two views, reflecting **positional accuracy** rather than just implant length.

Question 213: A 54-year-old man presents with a 6-month history of lower back pain and morning stiffness lasting 90 minutes. He reports the pain improves with exercise but not rest. He has a history of recurrent anterior uveitis and psoriasis. Examination reveals reduced lumbar spine flexion with a Schober's test measurement of 3 cm (normal >5 cm). What is the most appropriate initial investigation?

A. MRI lumbar spine
B. Plain radiograph of sacroiliac joints (Correct Answer)
C. HLA-B27 testing
D. Anti-CCP antibodies
E. Rheumatoid factor

Explanation: ***Plain radiograph of sacroiliac joints***- A **plain radiograph** is the most appropriate first-line investigation to look for **sacroiliitis**, which is the hallmark of axial spondyloarthritis.- Diagnostic findings include **erosions**, **sclerosis**, or **ankylosis** of the sacroiliac joints, confirming the skeletal involvement suggested by the abnormal **Schober's test**.*MRI lumbar spine*- While **MRI** is the gold standard for detecting **early/active inflammatory** changes (bone marrow edema), it is typically reserved for cases where plain films are negative but suspicion remains high.- An MRI of the **sacroiliac joints** is more diagnostic for this condition than an MRI of the lumbar spine specifically.*HLA-B27 testing*- **HLA-B27** is associated with ankylosing spondylitis but is not a diagnostic test because it can be positive in **healthy individuals**.- It is generally used to rule in or rule out spondyloarthritis in patients with **equivocal radiologic findings** or borderline clinical symptoms.*Anti-CCP antibodies*- These antibodies are highly specific for **rheumatoid arthritis**, which typically presents with **symmetrical polyarthritis** of small joints.- Rheumatoid arthritis does not involve the **sacroiliac joints** and does not present with inflammatory back pain improving with exercise.*Rheumatoid factor*- **Rheumatoid factor** is an insensitive and non-specific marker used primarily in the workup of **rheumatoid arthritis** or other connective tissue diseases.- Ankylosing spondylitis is a **seronegative spondyloarthropathy**, meaning patients are characteristically negative for rheumatoid factor.

Question 214: An 84-year-old man with end-stage dementia and complete functional dependence sustains a displaced intracapsular neck of femur fracture. He was non-ambulatory before the fracture and resided in a nursing home with full care. His family report he has been in considerable pain. What is the most appropriate management?

A. Total hip replacement
B. Cemented hemiarthroplasty
C. Uncemented hemiarthroplasty
D. Internal fixation with cannulated screws
E. Non-operative management with palliative care (Correct Answer)

Explanation: ***Non-operative management with palliative care***- In a patient with **end-stage dementia** who was **non-ambulatory** pre-injury, the goals of care shift from mobility restoration to **pain management** and dignity.- Surgical intervention in an elderly, **fully dependent** patient carries high perioperative risk and may not provide any clinical benefit or improvement in the **quality of life**.*Total hip replacement*- This procedure is reserved for active, **independent ambulators** with displaced intracapsular fractures to provide long-term joint durability.- It is highly inappropriate for a patient with **complete functional dependence** due to the high risk of **dislocation** and unnecessary surgical complexity.*Cemented hemiarthroplasty*- **Cemented hemiarthroplasty** is the standard of care for displaced intracapsular fractures in elderly patients who are **ambulatory**.- While medically sound for many, it is less suitable than **palliative care** here because the patient has no **pre-morbid mobility** to maintain.*Uncemented hemiarthroplasty*- **Uncemented** components are generally avoided in the elderly due to the risk of **periprosthetic fractures** and poorer long-term outcomes compared to cemented versions.- There is no clinical indication for any form of **arthroplasty** in a non-ambulatory patient with **end-stage dementia**.*Internal fixation with cannulated screws*- This approach is typically used for **undisplaced fractures** or in young patients to preserve the **native femoral head**.- In an 84-year-old with a **displaced** fracture, the risk of **avascular necrosis** and non-union is high, making this an unsuitable choice.

Question 215: A 25-year-old footballer presents with acute lower back pain after an awkward tackle. He has severe pain radiating down the posterior aspect of his right leg to his foot. On examination, he cannot stand on tiptoe on his right foot, has reduced sensation over the lateral border of his right foot, and has an absent right ankle reflex. Straight leg raise is positive at 30 degrees on the right. Which nerve root is most likely affected?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - Compression of the **S1 nerve root** is classically associated with an **absent ankle reflex** and sensory loss over the **lateral border of the foot** and sole. - Motor weakness in S1 radiculopathy manifests as difficulty with **plantarflexion**, leading to the inability to **stand on tiptoes**. *L3* - Affects the **L3 nerve root**, primarily causing weakness in **hip flexion** and **knee extension**. - Sensory loss is typically found over the **anterior thigh**, and it does not affect the ankle reflex. *L4* - Compression here results in a **diminished knee (patellar) reflex** and weakness in **knee extension** and foot inversion. - Sensory deficit is normally localized to the **medial leg** and the medial malleolus. *L5* - Characterized by weakness in **big toe extension** (hallux longus) and **foot dorsiflexion**, often presenting as **foot drop**. - Sensation is usually reduced over the **dorsum of the foot** and the first web space, but the **ankle reflex remains intact**. *S2* - Compression of **S2** is less common in isolated disc prolapse and typically involves sensory loss on the **posterior thigh**. - It is more frequently associated with **cauda equina syndrome** symptoms rather than isolated radiculopathy with an absent ankle reflex.

Question 216: What is the approximate risk of avascular necrosis of the femoral head following an undisplaced Garden I intracapsular neck of femur fracture treated with internal fixation?

A. Less than 5% (Correct Answer)
B. 10-15%
C. 20-30%
D. 40-50%
E. Greater than 60%

Explanation: ***Less than 5%*** - In a **Garden I** fracture, which is an **incomplete or impacted** fracture, the **retinacular vessels** usually remain intact, preserving the blood supply to the femoral head. - Due to the **undisplaced** nature of these fractures, internal fixation has a high success rate with a very low risk of **avascular necrosis (AVN)**. *10-15%* - This range is representative of the AVN risk for **Garden II** fractures, which are complete fractures but remain **undisplaced**. - Although the risk is higher than Garden I due to the nature of a **complete fracture**, it remains relatively low compared to displaced types. *20-30%* - This higher risk profile is typically associated with **Garden III** fractures, where there is **partial displacement** causing significant vascular compromise. - Displaced fractures interrupt the **medial circumflex femoral artery** branches, leading to a much higher chance of bone ischemia. *40-50%* - This is the expected rate of AVN for **Garden IV** fractures, where there is **complete displacement** and total loss of continuity between the fragments. - Because of this high likelihood of **vascular disruption**, surgeons often prefer **arthroplasty** over internal fixation in older patients. *Greater than 60%* - This extreme risk is generally not seen in standard undisplaced or even most primary displaced neck of femur fractures treated promptly. - Risks in this category are more likely associated with severe **comminution**, prolonged delay in surgery, or unsuccessful **internal fixation** of late-presenting fractures.

Question 217: A 62-year-old woman presents with a 4-week history of lower back pain that is worse at night and not relieved by rest. She has lost 6 kg in weight over the past 2 months. She is a non-smoker with no previous medical history. On examination, there is tenderness over the L3 vertebra. Blood tests show: Hb 102 g/L, WCC 8.2 × 10⁹/L, ESR 85 mm/hr, Calcium 2.85 mmol/L. What is the most appropriate next investigation?

A. MRI spine (Correct Answer)
B. Plain radiograph of lumbar spine
C. CT chest, abdomen and pelvis
D. Bone scan
E. Serum and urine protein electrophoresis

Explanation: ***MRI spine*** - This patient presents with multiple **red flags for spinal malignancy**: new onset back pain worse at night, not relieved by rest, significant **unexplained weight loss**, **anemia**, **elevated ESR**, and crucially, **hypercalcemia**, which is a strong indicator of **bone metastases** or **multiple myeloma**. - **MRI spine** is the most appropriate next investigation as it provides superior visualization of soft tissues, bone marrow, and the spinal canal, making it the gold standard for detecting vertebral metastases and assessing for **spinal cord compression**, which requires urgent intervention. *Plain radiograph of lumbar spine* - **Plain radiographs** have limited sensitivity for detecting early bony metastases, as a significant amount of bone destruction (30-50%) is required before lesions become visible. - They provide insufficient detail to assess for **spinal cord compression** or soft tissue involvement, which is a major concern in this clinical scenario. *CT chest, abdomen and pelvis* - A **CT scan of the chest, abdomen, and pelvis** is a crucial step for **staging malignancy** and identifying a primary tumor, but it is typically performed *after* initial spinal imaging (like MRI) has localized the spinal lesion and assessed for neurological compromise. - It is not the most appropriate *initial* investigation for directly evaluating the source of spinal pain and potential **cord compression**. *Bone scan* - A **bone scan** (Technetium-99m) is sensitive for detecting osteoblastic metastases but can miss purely **lytic lesions** (e.g., from multiple myeloma) and does not provide the detailed anatomical resolution needed to assess for **spinal cord compression** or soft tissue involvement. - It does not offer sufficient detail regarding the **spinal canal** or the specific nature of the lesion impacting the L3 vertebra. *Serum and urine protein electrophoresis* - These tests are essential for diagnosing **Multiple Myeloma**, a strong differential in this patient given the hypercalcemia, anemia, and elevated ESR. - However, they are **diagnostic lab tests**, not imaging modalities, and do not provide immediate information about the location or extent of spinal involvement or the presence of **cord compression**, which is the most urgent concern requiring imaging.

Question 218: A 70-year-old woman with a displaced intracapsular neck of femur fracture undergoes cemented hemiarthroplasty. During cement insertion, she suddenly becomes hypotensive with oxygen saturation dropping to 85%. Her ECG shows sinus tachycardia and she appears confused. What is the most likely diagnosis?

A. Fat embolism syndrome
B. Bone cement implantation syndrome (Correct Answer)
C. Pulmonary embolism from deep vein thrombosis
D. Myocardial infarction
E. Anaphylactic reaction to cement

Explanation: ***Bone cement implantation syndrome***- This syndrome is the most likely diagnosis due to the classic presentation of **hypotension**, **hypoxia (85% SpO2)**, and **altered consciousness** occurring specifically during the **cement insertion** phase of a cemented arthroplasty.- It results from the **embolization of bone marrow contents** and the systemic effects of **methylmethacrylate monomers**, leading to increased pulmonary vascular resistance, right ventricular strain, and cardiovascular collapse.*Fat embolism syndrome*- Typically presents **24-72 hours** after a long bone fracture or surgery, rather than acutely during the surgical application of cement.- Frequently characterized by a **triad** of respiratory distress, neurological symptoms, and a distinctive **petechial rash**, which is not seen here.*Pulmonary embolism from deep vein thrombosis*- While it causes sudden hypoxia and hypotension, the specific timing at the moment of **cementing** strongly favors an intraoperative event like BCIS over traditional thromboembolism.- **DVT-related PE** is less common during the surgery itself compared to the risk during the early post-operative recovery period.*Myocardial infarction*- An acute MI can cause sudden hypotension and tachycardia, but it would typically show specific **ECG changes** like ST-segment deviation rather than isolated sinus tachycardia.- This diagnosis does not explain the direct correlation with the **intraoperative cementation** process as specifically as BCIS does.*Anaphylactic reaction to cement*- True **IgE-mediated anaphylaxis** to bone cement is extremely rare in clinical practice.- While it can cause hypotension, it usually presents with **bronchospasm** (wheezing) and **mucocutaneous signs** like urticaria, which are not mentioned in this scenario.

Question 219: A 37-year-old woman with systemic lupus erythematosus presents with a 6-week history of insidious onset lower back pain that is worse in the morning and improves through the day with activity. She is currently taking prednisolone 15mg daily. On examination, there is tenderness over the lower lumbar spine but normal neurology. What is the most concerning underlying diagnosis that should be excluded?

A. Lumbar disc prolapse
B. Mechanical lower back pain
C. Vertebral compression fracture due to corticosteroid-induced osteoporosis (Correct Answer)
D. Spinal tuberculosis
E. Facet joint arthropathy

Explanation: ***Vertebral compression fracture due to corticosteroid-induced osteoporosis*** - Long-term **corticosteroid use** (prednisolone 15mg daily) is a major risk factor for **secondary osteoporosis**, leading to rapid bone loss and vertebral fractures even with minimal trauma. - The insidious onset lower back pain, worse in the morning and improving with activity, combined with steroid use, should prompt immediate exclusion of a **compression fracture**. *Lumbar disc prolapse* - This typically presents with **radicular pain** (sciatica) and often involves **neurological deficits** such as weakness or sensory loss, which are absent here. - The inflammatory pattern of pain (worse in the morning, better with activity) is less characteristic of a **mechanical disc herniation**. *Mechanical lower back pain* - Mechanical pain usually **worsens with activity** and **improves with rest**, the opposite of this patient's clinical presentation. - While common, it is not the "most concerning" diagnosis in an **immunosuppressed patient** on chronic steroids due to the higher risk of fragility fractures. *Spinal tuberculosis* - Often presents as **Pott’s disease** with constitutional symptoms like **weight loss**, **night sweats**, and fever, which are not mentioned in this case. - While SLE and steroids increase infection risk, the localized tenderness and direct steroid-induced bone loss make a **compression fracture** a more immediate and common concern. *Facet joint arthropathy* - Typically involves **degenerative changes** in older patients and presents with pain exacerbated by **spinal extension** and twisting movements. - It does not account for the significant risk of **steroid-induced bone fragility** seen in this 37-year-old patient with systemic lupus erythematosus.

Question 220: A 72-year-old woman undergoes dynamic hip screw fixation for an intertrochanteric neck of femur fracture. On day 3 post-operatively, she becomes acutely confused, develops a swinging pyrexia, and has a white cell count of 16.2 × 10⁹/L. Wound examination shows minimal bruising but no discharge or erythema. What is the most appropriate next investigation?

A. Blood cultures and commence broad-spectrum antibiotics immediately
B. CT chest to exclude pulmonary embolism
C. Ultrasound scan of the operative hip
D. Urinalysis and urine culture (Correct Answer)
E. Plain radiographs of the hip to check metalwork position

Explanation: ***Urinalysis and urine culture*** - **Urinary tract infections (UTIs)** are the most common source of **post-operative pyrexia** and acute confusion (delirium) in elderly patients, especially after hip surgery involving catheterization. - This investigation is a non-invasive, high-yield first step to confirm the most statistically likely cause of **leucocytosis** and systemic symptoms on day 3 post-op. *Blood cultures and commence broad-spectrum antibiotics immediately* - While **blood cultures** are part of a sepsis workup, antibiotics should ideally be targeted toward a likely source identified by initial screening like **urinalysis**. - Broad-spectrum antibiotics should not be started before obtaining appropriate cultures unless the patient is in **septic shock**, which is not indicated by the current vitals. *CT chest to exclude pulmonary embolism* - **Pulmonary embolism (PE)** usually presents with **tachycardia**, hypoxia, and sudden onset shortness of breath rather than a **swinging pyrexia** and high white cell count. - While post-operative immobility increases risk, it would not explain the **leucocytosis** and pyrexia as effectively as an infection. *Ultrasound scan of the operative hip* - Ultrasound is used to detect **deep collections** or **joint effusions**, but the examination showed no localizing signs like wound discharge or significant erythema. - It is a more specialized test that should follow a primary screen of common sites like the **chest** and **urinary tract**. *Plain radiographs of the hip to check metalwork position* - **Plain radiographs** are useful for checking secondary complications like **implant failure** or periprosthetic fractures but do not help in diagnosing **infective causes** of confusion. - Normal findings on a radiograph would not explain the patient's **acute delirium** or systemic inflammatory response.

Question 221: A 46-year-old woman presents with chronic lower back pain and is noted to have reduced lumbar lordosis and reduced lateral flexion of the spine. She reports early morning stiffness lasting 2 hours that improves with exercise. Inflammatory markers are normal. Which investigation would be most useful in establishing the underlying diagnosis?

A. HLA-B27 testing
B. MRI sacroiliac joints (Correct Answer)
C. Plain radiographs of lumbar spine
D. Rheumatoid factor and anti-CCP antibodies
E. Bone density scan (DEXA)

Explanation: ***MRI sacroiliac joints***- **MRI** is the most sensitive investigation for **axial spondyloarthropathy** as it can detect **bone marrow edema** and active inflammation before structural changes appear on X-rays.- It is the gold standard for diagnosing **non-radiographic axial spondyloarthropathy**, which is likely here given the symptoms despite normal inflammatory markers.*HLA-B27 testing*- While **HLA-B27** is present in about 90% of patients with ankylosing spondylitis, it is not diagnostic on its own as it is common in the **general population**.- A positive result supports the diagnosis but does not provide definitive evidence of **active sacroiliitis** or structural damage like imaging does.*Plain radiographs of lumbar spine*- X-rays may show late-stage features like **syndesmophytes** or a **'bamboo spine'**, but these findings often take years to develop and are frequently normal in early disease.- **Plain radiographs** lack the sensitivity to detect early inflammatory changes that an **MRI** can identify.*Rheumatoid factor and anti-CCP antibodies*- These markers are specific for **rheumatoid arthritis**, which typically presents with **symmetrical small joint arthritis** and worsens with activity.- **Ankylosing spondylitis** is a seronegative spondyloarthropathy, meaning these antibodies are characteristically absent.*Bone density scan (DEXA)*- A **DEXA scan** is used to evaluate for **osteoporosis** or osteopenia, which can be a secondary complication of chronic inflammation but is not a primary diagnostic tool for the condition.- It cannot identify the **inflammatory sacroiliitis** or spinal mobility restrictions characteristic of this patient's presentation.

Question 222: A 68-year-old woman sustains a trochanteric neck of femur fracture. Pre-injury she was independently mobile indoors and outdoors with a wheeled frame. The AO/OTA classification describes this as a 31-A2 fracture with posteromedial comminution. What is the most appropriate surgical fixation method?

A. Cannulated screw fixation
B. Dynamic hip screw with anti-rotation screw
C. Cephalomedullary intramedullary nail (Correct Answer)
D. Cemented hemiarthroplasty
E. Total hip replacement

Explanation: ***Cephalomedullary intramedullary nail***- For **unstable** intertrochanteric fractures, specifically **AO/OTA 31-A2** with **posteromedial comminution**, a cephalomedullary nail is the gold standard because it provides superior **biomechanical stability**.- The intramedullary location offers a **shorter lever arm** and acts as a **load-sharing** device, which prevents the collapse or medialization of the distal fragment often seen in unstable patterns.*Cannulated screw fixation*- This method is indicated for stable **undisplaced intracapsular** neck of femur fractures, not for extracapsular trochanteric fractures.- It lacks the structural stability required to support the significant forces acting on an **unstable intertrochanteric** fracture site.*Dynamic hip screw with anti-rotation screw*- While a **Dynamic Hip Screw (DHS)** is ideal for stable (31-A1) fractures, it has a high failure rate in **unstable 31-A2** fractures due to risk of **lateral wall blowout**.- Evidence suggests that in the presence of **posteromedial comminution**, the lateral cortex may not provide enough support for a sliding plate system, leading to **implant failure**.*Cemented hemiarthroplasty*- **Hemiarthroplasty** is the treatment of choice for **displaced intracapsular** fractures in the elderly, where the blood supply to the femoral head is compromised.- It is not a primary treatment for **trochanteric fractures** because the femoral head blood supply remains intact, and internal fixation is preferred over joint replacement.*Total hip replacement*- **Total hip replacement** is typically reserved for **intracapsular** fractures in active patients with pre-existing **arthritis** or those who meet specific criteria (e.g., NICE guidelines).- In the case of an **extracapsular trochanteric fracture**, a THR is overly invasive and significantly more complex than standard **intramedullary fixation**.

Question 223: A 59-year-old man with a 12-week history of lower back pain reports new onset bilateral buttock and leg pain that comes on after walking 200 metres and is relieved by sitting down or leaning forward. He can walk further when pushing a shopping trolley. Peripheral pulses are normal. What is the most likely diagnosis?

A. Peripheral arterial disease
B. Lumbar spinal stenosis (Correct Answer)
C. Bilateral sciatica from disc prolapse
D. Cauda equina syndrome
E. Degenerative spondylolisthesis

Explanation: ***Lumbar spinal stenosis*** - This patient presents with classic **neurogenic claudication**, characterized by leg pain elicited by walking and specifically relieved by **spinal flexion** (sitting down or leaning forward). - The "shopping trolley sign," where walking further while leaning on a trolley, is highly indicative as it widens the **spinal canal**, reducing pressure on the **cauda equina nerve roots**. *Peripheral arterial disease* - While this causes **vascular claudication**, the patient's **normal peripheral pulses** make this diagnosis unlikely. - Vascular claudication is typically relieved by **standing still** without needing spinal flexion, and it's not associated with the "shopping trolley sign." *Bilateral sciatica from disc prolapse* - Pain from a **disc prolapse** is often acute and typically **aggravated by sitting** or lumbar flexion, which is the opposite of this patient's relief by sitting and leaning forward. - Sciatica usually follows a **dermatomal pattern** and often involves positive straight leg raise tests, differing from the diffuse, distance-dependent pain described. *Cauda equina syndrome* - This is a medical emergency presenting with **saddle anesthesia**, acute urinary retention or bowel dysfunction, and progressive motor weakness, none of which are reported here. - The symptoms described are chronic and progressive **neurogenic claudication**, not the acute and severe neurological deficit of cauda equina syndrome. *Degenerative spondylolisthesis* - While **degenerative spondylolisthesis** can be an underlying anatomical cause of spinal stenosis, the most precise clinical diagnosis for the described symptoms of neurogenic claudication is **lumbar spinal stenosis**. - Spondylolisthesis refers to the slippage of one vertebra over another, which may lead to canal narrowing, but the symptomatic presentation is best termed lumbar spinal stenosis.

Question 224: A 77-year-old man with a displaced intracapsular neck of femur fracture is being considered for surgery. He has a history of ischaemic heart disease with previous MI 4 years ago, well-controlled atrial fibrillation on warfarin (INR 2.4), and moderate COPD. His abbreviated mental test score is 8/10. What is the most appropriate timing for surgical intervention?

A. Emergency surgery within 6 hours after reversing anticoagulation
B. Surgery within 36 hours after correction of INR (Correct Answer)
C. Delay surgery for 72 hours for full cardiology assessment
D. Surgery within 36 hours, continuing anticoagulation if regional anaesthesia contraindicated
E. Conservative management given multiple comorbidities

Explanation: ***Surgery within 36 hours after correction of INR*** - According to **NICE guidelines**, surgery for hip fractures should generally be performed within **36 hours** of admission to minimize mortality and morbidity. - For patients on **warfarin**, the **INR** must be corrected (typically to **<1.5**) before surgery using agents like Vitamin K or prothrombin complex concentrate to ensure safe hemostasis, which should be achieved within the 36-hour window. *Emergency surgery within 6 hours after reversing anticoagulation* - **Emergency surgery within 6 hours** is typically reserved for highly unstable fractures, those with **neurovascular compromise**, or polytrauma, none of which are indicated here. - While anticoagulation needs reversal, the 6-hour timeframe is overly aggressive and not the standard for a stable **displaced intracapsular neck of femur fracture**. *Delay surgery for 72 hours for full cardiology assessment* - Delaying surgery beyond **36-48 hours** significantly increases the risk of **postoperative complications** such as pneumonia, pressure ulcers, and deep vein thrombosis, and higher mortality rates. - Although the patient has **ischaemic heart disease**, his MI was 4 years ago and his condition is described as "well-controlled"; comprehensive medical optimization should occur in parallel with surgical planning rather than causing a prolonged delay. *Surgery within 36 hours, continuing anticoagulation if regional anaesthesia contraindicated* - Proceeding with surgery with an **INR of 2.4** carries a substantial risk of **significant intraoperative and postoperative bleeding**, which is unacceptable for major orthopaedic surgery. - Even if **regional anaesthesia** is contraindicated, **general anaesthesia** still requires a corrected INR to mitigate bleeding risks, especially in proximity to major blood vessels. *Conservative management given multiple comorbidities* - **Conservative management** of a displaced hip fracture in an elderly patient carries an extremely high risk of **complications** such as pneumonia, pressure sores, pain, and deep vein thrombosis, with poor long-term functional outcomes and high mortality. - Despite his comorbidities, surgical fixation or replacement offers the best chance for **pain relief**, **early mobilization**, and a return to baseline function, which is critical for maintaining quality of life.

Question 225: A 53-year-old heavy goods vehicle driver presents with a 3-week history of mechanical lower back pain with no radiation. He has no red flag symptoms. Neurological examination is normal. He is worried about his ability to work. What is the most appropriate management advice regarding return to work?

A. Advise complete bed rest for 2 weeks before considering return to work
B. Recommend remaining off work until pain has completely resolved
C. Advise early return to normal activities including work, with temporary modified duties if needed (Correct Answer)
D. Certify unfit for work for 6 weeks and arrange physiotherapy
E. Advise against returning to driving duties and recommend permanent job modification

Explanation: ***Advise early return to normal activities including work, with temporary modified duties if needed*** - For **non-specific mechanical back pain** without **red flags** or neurological deficits, guidelines strongly recommend staying active and an **early return to work** to prevent chronicity and deconditioning. - **Temporary modified duties** or a **graded return to work** facilitates a smoother reintegration into occupational activities, managing symptoms while maintaining function. *Advise complete bed rest for 2 weeks before considering return to work* - Prolonged **bed rest** is contraindicated for mechanical back pain as it delays recovery, leads to muscle **deconditioning**, and increases the risk of chronic pain. - Current evidence advocates for **minimal or no bed rest**, with an emphasis on maintaining usual activities as tolerated. *Recommend remaining off work until pain has completely resolved* - Waiting for **complete pain resolution** is often an unrealistic goal and can foster **fear-avoidance behaviors** and increase the likelihood of long-term work disability. - Patients should be encouraged to self-manage symptoms while gradually increasing their activity levels and returning to work, as some discomfort may persist during recovery. *Certify unfit for work for 6 weeks and arrange physiotherapy* - A **6-week absence** for acute non-specific mechanical back pain is excessive and is recognized as a **yellow flag** for the development of chronic disability. - While **physiotherapy** can be helpful, it should support an active recovery and early return to work, rather than being a justification for prolonged time off. *Advise against returning to driving duties and recommend permanent job modification* - There is **no medical justification** in this clinical scenario (absence of red flags, normal neurological exam) to suggest a permanent disability or to restrict the patient from driving. - Recommending **permanent job modification** at 3 weeks is premature; focus should be on recovery, ergonomic advice, and temporary adjustments if required.

Question 226: A 69-year-old man undergoes cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture. During cement insertion, he suddenly develops hypotension (BP 75/40 mmHg), hypoxia (SpO2 82%), and loss of consciousness. What is the underlying pathophysiological mechanism of this complication?

A. Anaphylactic reaction to bone cement methylmethacrylate
B. Embolization of fat, air, cement particles and marrow contents causing pulmonary hypertension and right heart strain (Correct Answer)
C. Acute left ventricular failure due to cement toxicity
D. Intraoperative cerebrovascular accident due to cement embolus
E. Vasovagal response to surgical pain and stress

Explanation: ***Embolization of fat, air, cement particles and marrow contents causing pulmonary hypertension and right heart strain*** - This clinical presentation is characteristic of **Bone Cement Implantation Syndrome (BCIS)**, where high intramedullary pressure during cement insertion forces marrow contents into the **venous circulation**. - This leads to increased **pulmonary vascular resistance**, resulting in **pulmonary hypertension**, acute **right ventricular strain**, and subsequent **hypotension** and **hypoxia**. *Anaphylactic reaction to bone cement methylmethacrylate* - While bone cement (methylmethacrylate) can rarely cause hypersensitivity, a **true systemic anaphylactic reaction** leading to such profound cardiorespiratory collapse is extremely uncommon. - The immediate onset linked to **cement pressurization** during orthopaedic surgery points more strongly towards a mechanical embolic event rather than an immune-mediated response. *Acute left ventricular failure due to cement toxicity* - Although some components of bone cement can have minor direct **vasodilatory effects**, the primary pathophysiology in BCIS is typically **right heart strain** from pulmonary embolism, not primary acute left ventricular failure. - Systemic hypotension in BCIS is predominantly a consequence of severe right ventricular dysfunction and subsequent **reduced left ventricular preload**. *Intraoperative cerebrovascular accident due to cement embolus* - An intraoperative **cerebrovascular accident (CVA)** would typically manifest with focal neurological deficits, which are not the predominant features described here (hypotension, hypoxia, loss of consciousness). - For an embolus to reach the cerebral circulation, a **right-to-left shunt** (e.g., patent foramen ovale) would generally be required, and the primary issue is cardiorespiratory collapse. *Vasovagal response to surgical pain and stress* - A **vasovagal response** typically causes **bradycardia** and transient hypotension, but it is rarely associated with such severe and persistent **hypoxia (SpO2 82%)** and loss of consciousness. - The specific timing during the high-risk phase of **cement insertion** in an elderly patient points toward a more severe, cement-related complication.

Question 227: A 41-year-old woman presents with a 4-month history of lower back pain radiating down the posterior aspect of her right leg to the heel. She describes paraesthesia in the lateral aspect of her foot and weakness when walking on her toes. Straight leg raise is positive at 40 degrees on the right. Which nerve root is most likely affected?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - The patient's symptoms of pain radiating down the **posterior aspect of the leg to the heel**, paraesthesia in the **lateral aspect of the foot**, and weakness with **plantarflexion** (difficulty walking on toes) are classic signs of **S1 radiculopathy**. - A positive **straight leg raise** further indicates nerve root compression, and S1 involvement is strongly suggested by the sensory distribution and motor deficit. *L3* - **L3 radiculopathy** typically presents with pain and sensory changes in the **anterior thigh** and medial aspect of the knee. - Motor weakness would involve **hip flexion** and **knee extension**, which are distinct from the patient's symptoms. *L4* - Symptoms of **L4 radiculopathy** primarily involve pain and sensory loss over the **medial leg** and ankle. - Weakness would be noted in **knee extension** (quadriceps) and a diminished **patellar reflex** would be expected. *L5* - **L5 radiculopathy** characteristically causes pain and sensory loss in the **lateral aspect of the leg**, **dorsum of the foot**, and the first web space. - Motor weakness typically affects **foot dorsiflexion** and **big toe extension**, leading to a **foot drop**, not difficulty walking on toes. *S2* - **S2 nerve root** involvement usually presents with sensory deficits in the **posterior thigh** and perineum. - While it contributes to plantarflexion, the specific **lateral aspect of the foot** and heel sensory loss is a key differentiating feature of S1.

Question 228: A 76-year-old woman with Parkinson's disease sustains an undisplaced intracapsular neck of femur fracture. She was independently mobile with a walking stick prior to the fall. Her comorbidities include controlled hypertension and osteoporosis. What is the most appropriate surgical management?

A. Internal fixation with cannulated screws
B. Total hip replacement (Correct Answer)
C. Cemented hemiarthroplasty
D. Uncemented hemiarthroplasty
E. Dynamic hip screw fixation

Explanation: ***Total hip replacement***- According to **NICE guidelines**, patients who are fit, medically stable, and able to **walk outdoors** independently with no more than one stick before the fracture should be offered a **total hip replacement (THR)**.- THR provides superior **long-term functional outcomes**, lower revision rates, and better quality of life compared to hemiarthroplasty in active elderly patients.*Internal fixation with cannulated screws*- While used for **undisplaced intracapsular fractures**, it carries a high risk (20-30%) of **avascular necrosis** and non-union in the elderly population.- In patients over age 65, **arthroplasty** is generally preferred over fixation to allow immediate weight-bearing and avoid late failure.*Cemented hemiarthroplasty*- This is the treatment of choice for patients who do not meet the criteria for THR, such as those with **significant cognitive impairment** or limited pre-injury mobility.- Although this patient has **Parkinson's disease**, her high functional status (mobile with one stick) makes her a better candidate for the superior longevity of **THR**.*Uncemented hemiarthroplasty*- **Uncemented hemiarthroplasty** is generally discouraged as it is associated with a higher risk of **periprosthetic fractures** and slower recovery in older patients.- **Cemented fixation** is evidence-based and preferred to ensure better implant stability and lower post-operative pain.*Dynamic hip screw fixation*- A **dynamic hip screw (DHS)** is the gold standard for **extracapsular (trochanteric)** fractures, not intracapsular fractures.- Using a DHS for an **intracapsular fracture** would be inappropriate as it does not address the risk of vascular compromise to the femoral head.

Question 229: Which anatomical feature determines whether a neck of femur fracture is classified as intracapsular or extracapsular?

A. The attachment of the joint capsule from the intertrochanteric line anteriorly to the intertrochanteric crest posteriorly (Correct Answer)
B. The position relative to the lesser trochanter
C. The blood supply from the medial and lateral circumflex femoral arteries
D. The location above or below the level of the greater trochanter
E. The orientation of the fracture line relative to Shenton's line

Explanation: ***The attachment of the joint capsule from the intertrochanteric line anteriorly to the intertrochanteric crest posteriorly***- This anatomical boundary precisely determines whether a neck of femur fracture is **intracapsular** (within the joint capsule) or **extracapsular** (outside the joint capsule).- The **joint capsule** attaches anteriorly to the intertrochanteric line and posteriorly to a line proximal to the intertrochanteric crest.*The position relative to the lesser trochanter*- The **lesser trochanter** is a landmark for classifying fractures as subtrochanteric, which are typically **extracapsular** fractures.- While important for surgical planning and describing fracture patterns, it does not define the **capsular limits** of the hip joint itself.*The blood supply from the medial and lateral circumflex femoral arteries*- The **blood supply** is a crucial clinical consideration, as intracapsular fractures often disrupt the **retinacular vessels**, leading to a high risk of **avascular necrosis**.- However, the classification of the fracture as intracapsular or extracapsular is based on its anatomical location relative to the capsule, not on the compromise of the **femoral head blood supply**.*The location above or below the level of the greater trochanter*- The **greater trochanter** is a prominent bony landmark primarily used to define **extracapsular** fractures, such as intertrochanteric fractures.- It does not serve as the direct anatomical determinant for the boundary of the **joint capsule** itself.*The orientation of the fracture line relative to Shenton's line*- **Shenton's line** is a radiographic arc formed by the medial border of the femoral neck and the inferior border of the superior pubic ramus, used to identify hip **dislocations** or femoral neck shortening.- It is a **radiological sign** indicating the integrity of the hip joint, not an anatomical feature defining the intracapsular or extracapsular classification of a fracture.

Question 230: A 65-year-old woman presents with a 6-week history of progressively worsening lower back pain. She describes the pain as constant, worse at night, and not relieved by rest. She has lost 5 kg in weight over the past 2 months. Blood tests show: Hb 102 g/L, ESR 78 mm/hr, corrected calcium 2.85 mmol/L, ALP 245 U/L. What is the single most important next investigation?

A. Whole spine MRI (Correct Answer)
B. Bone density scan (DEXA)
C. Plain radiographs of lumbar spine
D. CT abdomen and pelvis
E. Lumbar puncture

Explanation: ***Whole spine MRI*** - This patient presents with multiple **red flags** for spinal malignancy, including constant pain worse at night, **weight loss**, and laboratory markers like **anemia**, **hypercalcemia**, and a markedly raised **ESR**.- **Whole spine MRI** is the gold-standard investigation to detect **metastatic disease** in the spine, assess bone marrow involvement, and identify potential **spinal cord compression**, which is critical given her symptoms.*Bone density scan (DEXA)* - **DEXA scans** are used to diagnose **osteoporosis** by measuring bone mineral density and are not suitable for investigating acute, progressive back pain with systemic symptoms.- It cannot detect **malignant infiltration** or provide detailed structural information about the vertebral column in the context of suspected cancer.*Plain radiographs of lumbar spine* - X-rays are **insensitive for early malignancy**, as significant bone destruction (up to 30-50%) must occur before a lesion becomes visible.- They lack the detail to assess **soft tissue involvement**, bone marrow changes, or potential **spinal cord compression**.*CT abdomen and pelvis* - While a **CT abdomen and pelvis** may help in locating a **primary tumor**, it is not the most important *next* investigation for the direct cause of the patient's back pain.- The immediate priority is to evaluate the spine itself for malignancy and potential **neurological compromise** before staging the systemic disease.*Lumbar puncture* - This procedure is primarily used to investigate **meningitis**, encephalitis, or **subarachnoid hemorrhage**, which do not match this patient's presentation.- Performing a lumbar puncture in the presence of a potential **spinal mass** can be dangerous and provides no diagnostic value for suspected bone metastases.

Question 231: A 71-year-old man undergoes total hip replacement for a displaced intracapsular neck of femur fracture. Post-operatively on day 2, he develops acute onset confusion, respiratory distress with oxygen saturation of 88% on room air, tachycardia, and petechial rash over his chest. What is the most likely diagnosis?

A. Pulmonary embolism
B. Fat embolism syndrome (Correct Answer)
C. Bone cement implantation syndrome
D. Hospital-acquired pneumonia
E. Acute myocardial infarction

Explanation: ***Fat embolism syndrome*** - This patient exhibits the classic triad of **fat embolism syndrome (FES)**: respiratory distress, neurological impairment (**confusion**), and a pathognomonic **petechial rash** post-orthopaedic surgery. - FES typically manifests **24-72 hours** after a long bone or pelvic fracture/surgery due to the release of fat globules into the systemic circulation. *Pulmonary embolism* - While it presents with **tachycardia** and **respiratory distress**, it does not typically cause a **petechial rash** or immediate acute confusion. - **Venous thromboembolism** usually develops slightly later in the post-operative period compared to the rapid onset seen with fat globules. *Bone cement implantation syndrome* - This typically occurs **intraoperatively** (during cementation or prosthesis insertion) or in the immediate recovery period, not 2 days post-operatively. - It is characterized by sudden **hypotension**, hypoxia, and cardiac arrhythmias due to the release of methyl methacrylate into the bloodstream. *Hospital-acquired pneumonia* - While pneumonia causes hypoxia and distress, it would usually be accompanied by **fever**, productive cough, and specific **infiltrates on chest X-ray**. - Fever and hypoxia could explain confusion in the elderly (delirium), but pneumonia does not explain the **petechial rash** on the chest. *Acute myocardial infarction* - MI should be considered in elderly post-op patients but presents primarily with **chest pain**, ECG changes, or elevated **troponins**. - It does not present with a **petechial rash**, which is a highly specific marker for fat embolization in this clinical context.

Question 232: A 48-year-old man presents with a 2-day history of severe lower back pain and bilateral leg weakness. He reports difficulty urinating and reduced sensation in the perineal region. On examination, he has bilateral lower limb weakness with absent ankle reflexes and decreased perianal sensation. What is the most appropriate immediate management?

A. Arrange urgent MRI spine and contact neurosurgery (Correct Answer)
B. Prescribe NSAIDs and arrange outpatient physiotherapy
C. Perform lumbar puncture to exclude infection
D. Request CT spine within 24 hours
E. Admit for intravenous antibiotics and blood cultures

Explanation: ***Arrange urgent MRI spine and contact neurosurgery*** - The patient's presentation with severe lower back pain, bilateral leg weakness, difficulty urinating, and **saddle anesthesia** (reduced perianal sensation) is classic for **Cauda Equina Syndrome (CES)**. - CES is a **surgical emergency** requiring immediate **MRI of the spine** to identify the compressive lesion and urgent **neurosurgical decompression** to prevent permanent neurological deficits. *Prescribe NSAIDs and arrange outpatient physiotherapy* - This management is appropriate for **uncomplicated mechanical back pain** but is highly dangerous and inadequate for a patient with **red flag symptoms** indicating CES. - Delaying diagnosis and intervention for CES with conservative management can result in irreversible **bladder, bowel, and sexual dysfunction**. *Perform lumbar puncture to exclude infection* - While an infectious process like a spinal epidural abscess can cause CES, a **lumbar puncture** is not the primary diagnostic test for identifying a compressive lesion. - **Urgent MRI** is the gold standard for visualizing the spinal canal and nerve roots, and it must precede other less specific investigations in this emergent situation. *Request CT spine within 24 hours* - A **CT scan** is inferior to **MRI** for visualizing soft tissue structures such as disc herniations, ligaments, or tumors, which are common causes of CES. - A **24-hour delay** in imaging is unacceptable for suspected CES; timely diagnosis and surgical decompression within hours are crucial for preserving neurological function. *Admit for intravenous antibiotics and blood cultures* - Although **spinal epidural abscess** is a differential diagnosis for CES, initiating empiric **antibiotics** without a definitive diagnosis from **urgent imaging** is inappropriate. - The immediate priority is to identify the cause of compression via MRI and arrange for surgical management, as antibiotics alone will not relieve acute mechanical compression.

Question 233: A 74-year-old woman sustains a neck of femur fracture following a low-energy fall. The fracture line is located at the junction between the femoral neck and the intertrochanteric region. Which anatomical classification best describes this fracture pattern?

A. Intracapsular fracture
B. Basicervical fracture (Correct Answer)
C. Intertrochanteric fracture
D. Subtrochanteric fracture
E. Transcervical fracture

Explanation: ***Basicervical fracture***- A **basicervical fracture** occurs specifically at the base of the femoral neck, representing the junction between the neck and the **intertrochanteric region**.- While technically **extracapsular**, it is physiologically unique because it lacks the cancellous bone interlocking found in intertrochanteric fractures, often requiring stable **internal fixation**.*Intracapsular fracture*- These occur within the **hip joint capsule** and include subcapital and transcervical patterns.- They carry a high risk of damaging the **medial circumflex femoral artery**, leading to **avascular necrosis (AVN)** of the femoral head.*Intertrochanteric fracture*- This fracture pattern occurs further distal than a basicervical fracture, specifically between the **greater and lesser trochanters**.- It is characterized by being **extracapsular** and typically having a better blood supply and higher **healing potential** than neck fractures.*Subtrochanteric fracture*- This occurs in the region extending from the **lesser trochanter** to approximately 5 cm distal into the femoral shaft.- These are often associated with high-energy trauma or **atypical patterns** related to long-term bisphosphonate use.*Transcervical fracture*- This is a type of **intracapsular fracture** that occurs across the mid-portion of the **femoral neck**.- Unlike basicervical fractures, these are located entirely within the capsule and are more likely to result in **non-union** if blood supply is disrupted.

Question 234: A 79-year-old woman sustains a displaced intracapsular neck of femur fracture. She was previously independent and walked daily without aids. She has mild cognitive impairment (AMTS 8/10) but manages her own finances and medications. Her medical history includes well-controlled hypertension. What is the most appropriate surgical management to optimize her functional outcome?

A. Hemiarthroplasty
B. Total hip replacement (Correct Answer)
C. Cannulated screw fixation
D. Dynamic hip screw
E. Conservative management with early mobilisation

Explanation: ***Total hip replacement*** - This patient meets the criteria for **Total hip replacement (THR)**: she was independently mobile outdoors without an aid, has an **AMTS 8/10**, and is medically fit for the procedure. - THR is preferred in high-functioning elderly patients with **displaced intracapsular fractures** because it offers superior long-term **functional outcomes**, less pain, and lower re-operation rates compared to hemiarthroplasty. *Hemiarthroplasty* - This is typically reserved for patients who are less active, have **significant cognitive impairment**, or use mobility aids outdoors pre-injury. - While it has a lower **dislocation rate** and shorter operative time, it results in inferior long-term functional mobility and a higher risk of **acetabular wear** (erosion) in active patients. *Cannulated screw fixation* - This method of **internal fixation** is generally reserved for **undisplaced** intracapsular fractures or very young patients where preserving the femoral head is a priority. - In a 79-year-old with a **displaced** fracture, fixation carries an unacceptably high risk of **avascular necrosis** and non-union (failure of fixation). *Dynamic hip screw* - A **Dynamic hip screw (DHS)** is the gold standard surgical treatment for **extracapsular (trochanteric)** hip fractures, not intracapsular ones. - Applying a DHS to a displaced intracapsular fracture does not address the disrupted **blood supply** to the femoral head and is likely to result in surgical failure. *Conservative management with early mobilisation* - This approach is rarely indicated and is associated with high **mortality**, chronic pain, and permanent loss of mobility in hip fracture patients. - It is only considered in patients with extremely high **perioperative risk** where death is imminent and surgery would not improve comfort.

Question 235: A 56-year-old builder presents with a 12-month history of lower back pain and morning stiffness. Examination reveals reduced lumbar spine flexion (modified Schober's test 3cm, normal >5cm) and reduced chest expansion (2cm, normal >5cm). Radiographs show bilateral sacroiliitis and squaring of vertebral bodies. He is HLA-B27 positive. What is the most appropriate initial pharmacological management?

A. Oral prednisolone 30mg daily
B. Methotrexate 15mg weekly
C. NSAIDs (e.g., naproxen) regularly with physiotherapy (Correct Answer)
D. Anti-TNF biological therapy (e.g., adalimumab)
E. Sulfasalazine 2g daily

Explanation: ***NSAIDs (e.g., naproxen) regularly with physiotherapy*** - **NSAIDs** are the **first-line pharmacological treatment** for axial spondyloarthritis, including ankylosing spondylitis, effectively reducing pain and stiffness caused by inflammation. - **Physiotherapy** is crucial alongside medication to maintain **spinal mobility**, improve posture, and prevent functional decline in patients with ankylosing spondylitis. *Oral prednisolone 30mg daily* - **Systemic corticosteroids** have limited efficacy for the axial (spinal and sacroiliac) symptoms of ankylosing spondylitis and are not recommended as initial therapy. - They are typically reserved for treating **peripheral arthritis** or **extra-articular manifestations** like acute anterior uveitis, often via local injection rather than high-dose oral administration. *Methotrexate 15mg weekly* - **Methotrexate**, a conventional DMARD, has **no proven efficacy** for the axial symptoms (sacroiliitis, spinal stiffness) that characterize this patient's presentation. - Its use is primarily limited to patients with significant **peripheral arthritis** associated with spondyloarthritis. *Anti-TNF biological therapy (e.g., adalimumab)* - **Anti-TNF biological therapies** are highly effective but are reserved for patients who have failed an adequate trial of at least **two different NSAIDs**. - They are considered when there is persistent **high disease activity** despite conventional management, not as initial treatment. *Sulfasalazine 2g daily* - **Sulfasalazine** is ineffective for managing the axial symptoms, such as **sacroiliitis** and **spinal stiffness**, which are prominent in this patient. - Like methotrexate, its role in spondyloarthritis is confined to treating **peripheral joint involvement**.

Question 236: A 73-year-old man undergoes a dynamic hip screw for an intertrochanteric neck of femur fracture. Post-operatively on day 2, he develops sudden onset shortness of breath, confusion, and petechial rash over his chest and conjunctiva. His oxygen saturation is 88% on room air. Blood results show thrombocytopenia and hypocalcaemia. What is the most likely diagnosis?

A. Pulmonary embolism
B. Fat embolism syndrome (Correct Answer)
C. Bone cement implantation syndrome
D. Acute respiratory distress syndrome
E. Allergic reaction to surgical materials

Explanation: ***Fat embolism syndrome*** - This diagnosis is characterized by the classic triad of **respiratory distress** (shortness of breath, low SpO2), **neurological impairment** (confusion), and a **petechial rash** over the chest and conjunctiva, typically occurring 24-72 hours after long bone fracture surgery.- Biochemical markers like **thrombocytopenia** (due to platelet aggregation and consumption) and **hypocalcaemia** (from fatty acids binding calcium) are classic laboratory findings in this syndrome.*Pulmonary embolism* - While it causes sudden **shortness of breath** and hypoxia, a **petechial rash** and **thrombocytopenia** are not typical features of a standard pulmonary embolism.- It usually presents later in the post-operative period unless there is a pre-existing deep vein thrombosis.*Bone cement implantation syndrome* - This condition occurs **intraoperatively** or immediately post-operatively, during the insertion of bone cement, leading to hypotension, hypoxia, and cardiac arrhythmias.- The patient underwent a **dynamic hip screw (DHS)**, which is an **uncemented** fixation, and symptoms appeared on day 2, not during surgery.*Acute respiratory distress syndrome* - ARDS is characterized by severe hypoxemia and **bilateral pulmonary infiltrates** on imaging, but it does not primarily account for the distinctive **petechial rash** or **neurological symptoms**.- While ARDS can be a consequence of severe fat embolism, it doesn't encompass the full systemic and dermatological presentation seen in this case.*Allergic reaction to surgical materials* - Anaphylaxis or severe allergy would typically manifest with **urticaria** (hives), angioedema, or bronchospasm, usually occurring **immediately** or very shortly after exposure.- A **petechial rash**, confusion, thrombocytopenia, and hypocalcaemia are not characteristic features of an allergic reaction to surgical materials.

Question 237: A 44-year-old woman presents with chronic lower back pain and is found to have a large central disc prolapse at L4/L5 on MRI. She has mild bilateral leg pain but no motor weakness, normal reflexes, and normal bladder function. She has failed 8 weeks of conservative management including physiotherapy and analgesia. What is the most appropriate next step in management?

A. Urgent surgical decompression
B. Epidural steroid injection (Correct Answer)
C. Continue conservative management for another 4 weeks
D. Arrange nerve conduction studies
E. Commence oral prednisolone 40mg daily

Explanation: ***Epidural steroid injection***- In patients with chronic **radicular pain** due to disc prolapse who have failed initial conservative management (at least 6 weeks), **epidural steroid injections** are a recommended next step to reduce inflammation and provide symptomatic relief.- This intervention aims to manage pain effectively without the immediate risks of surgery, often combining a **local anesthetic** with **corticosteroids**.*Urgent surgical decompression*- This is reserved for emergency presentations like **Cauda Equina Syndrome**, characterized by saddle anesthesia, bladder dysfunction, or progressive **motor weakness**, none of which this patient has.- While surgery is an option after conservative failure, "urgent" decompression is not clinically indicated for stable **radiculopathy** without neurological deficits.*Continue conservative management for another 4 weeks*- The patient has already completed **8 weeks of conservative therapy** (physiotherapy and analgesia) without success, meeting the threshold to escalate care.- Continuing the same path without intervention is unlikely to yield further benefit and delays relief for a patient with persistent **radiculopathy**.*Arrange nerve conduction studies*- **Nerve conduction studies (NCS)** are generally used to diagnose peripheral neuropathies or clarify nerve compression if the diagnosis is uncertain; here, the **MRI** has already localized the pathology.- These studies provide functional data but do not guide the immediate therapeutic management for a confirmed **disc prolapse**.*Commence oral prednisolone 40mg daily*- **Oral corticosteroids** are not standard evidence-based treatment for spinal disc prolapse and lack the efficacy of localized delivery via an epidural.- Systemic steroids carry a significant side-effect profile and do not provide the targeted anti-inflammatory benefit needed at the **nerve root**.

Question 238: A 58-year-old man with a 20-year history of ankylosing spondylitis sustains a neck of femur fracture following minimal trauma. Radiographs show a transverse extracapsular fracture through osteoporotic bone. His bone mineral density T-score is -3.2. In addition to surgical fixation, which long-term management strategy is most important to reduce future fracture risk?

A. Increase calcium and vitamin D supplementation only
B. Commence bisphosphonate therapy and ensure adequate calcium/vitamin D (Correct Answer)
C. Prescribe calcitonin and arrange annual DEXA scans
D. Start strontium ranelate and physiotherapy
E. Prescribe raloxifene and recommend weight-bearing exercise

Explanation: ***Commence bisphosphonate therapy and ensure adequate calcium/vitamin D***- The patient has **severe osteoporosis** (T-score -3.2) and a **fragility fracture**, making **bisphosphonates** the first-line treatment to inhibit bone resorption and reduce future fracture risk.- **Calcium and vitamin D** are essential co-factors, providing the necessary minerals for bone formation and optimizing the effectiveness of anti-resorptive therapies.*Increase calcium and vitamin D supplementation only*- While necessary, **calcium and vitamin D supplementation alone** are insufficient to manage **severe osteoporosis** (T-score -3.2) and prevent further fragility fractures.- These supplements are supportive but do not directly address the underlying **osteoclastic overactivity** seen in osteoporosis, which requires more potent agents.*Prescribe calcitonin and arrange annual DEXA scans*- **Calcitonin** has a limited role in osteoporosis management, primarily for short-term pain relief in acute vertebral fractures, and is not effective for **long-term fracture prevention**.- **Annual DEXA scans** are generally not recommended as bone density changes slowly; scans every 2 years are typically sufficient to monitor treatment efficacy.*Start strontium ranelate and physiotherapy*- **Strontium ranelate** is no longer recommended as a first-line treatment for osteoporosis due to concerns about increased risk of **cardiovascular events** and **venous thromboembolism**.- **Physiotherapy** is important for maintaining mobility and function in ankylosing spondylitis but does not replace pharmacological therapy for **severe osteoporosis** and fracture prevention.*Prescribe raloxifene and recommend weight-bearing exercise*- **Raloxifene** is a selective estrogen receptor modulator (SERM) primarily indicated for **postmenopausal osteoporosis** in women and is not appropriate for male patients.- **Weight-bearing exercise** can help maintain bone density but is insufficient as a standalone treatment for established **severe osteoporosis** with a T-score of -3.2 and a history of fragility fracture.

Question 239: Which classification system for intracapsular neck of femur fractures is based on the degree of displacement and comminution visible on anteroposterior and lateral radiographs, and correlates with risk of avascular necrosis?

A. AO/OTA classification
B. Garden classification (Correct Answer)
C. Pauwels classification
D. Vancouver classification
E. Neer classification

Explanation: ***Garden classification*** - This system classifies **intracapsular femoral neck fractures** into four stages based on the degree of **displacement** and the alignment of **medial trabeculae** visible on anteroposterior and lateral radiographs. - It is crucial for assessing the risk of **avascular necrosis (AVN)** of the femoral head, with higher Garden stages (III and IV) indicating significant displacement and a greater risk of vascular compromise. *AO/OTA classification* - This is a comprehensive, **alphanumeric system** designed for general fracture classification across all bones, used for standardizing descriptions in research and clinical practice. - While it can describe femoral neck fractures, it does not specifically focus on the **trabecular alignment** or directly correlate with **avascular necrosis risk** as precisely as the Garden system. *Pauwels classification* - This system classifies **femoral neck fractures** based on the **angle of the fracture line** relative to the horizontal plane. - Its primary utility is to assess the **mechanical stability** and predict the risk of non-union by quantifying shear forces, not primarily the degree of displacement or AVN risk. *Vancouver classification* - This classification system is specifically used for **periprosthetic femoral fractures**, which occur in the femur around or distal to an existing hip prosthesis. - It considers factors like the fracture location, the **stability of the implant**, and the quality of the host bone, entirely distinct from an *intact* femoral neck fracture. *Neer classification* - This system is exclusively used for classifying **proximal humerus fractures**, not fractures of the femoral neck. - It is based on the number of **displaced anatomical segments** (head, greater tuberosity, lesser tuberosity, shaft) and is unrelated to hip fractures.

Question 240: A 67-year-old woman with metastatic breast cancer presents with a 4-week history of progressively worsening mid-thoracic back pain, worse at night and not relieved by analgesia. She now reports difficulty walking and numbness in both legs. On examination, she has a sensory level at T8, bilateral lower limb weakness (power 3/5), and brisk reflexes with upgoing plantars. What is the most appropriate immediate investigation?

A. Plain radiographs of thoracic spine
B. Urgent whole spine MRI (Correct Answer)
C. CT thoracic spine
D. Bone scan
E. PET-CT scan

Explanation: ***Urgent whole spine MRI***- This patient presents with signs of **metastatic spinal cord compression (MSCC)**, an oncological emergency requiring prompt diagnosis to prevent permanent neurological deficits.- **Urgent whole spine MRI** is the **gold standard** as it provides comprehensive visualization of the spinal cord, epidural space, and can identify the exact level and extent of compression, including multiple lesions.*Plain radiographs of thoracic spine*- Plain X-rays have low sensitivity for visualizing the **spinal cord** and **soft tissue compression**, which are critical in MSCC.- While they might show **vertebral collapse** or lytic lesions, a normal radiograph cannot exclude cord compression and should not delay definitive imaging.*CT thoracic spine*- CT offers superior detail of **bony structures** and potential fractures but is inferior to MRI for evaluating **spinal cord** and **epidural soft tissue compression**.- A CT of only the thoracic spine might miss **synchronous lesions** in other spinal regions, which can occur in patients with metastatic disease.*Bone scan*- Radionuclide bone scans are highly sensitive for detecting **osteoblastic metastases** but do not provide information regarding the direct compression of the **spinal cord** or thecal sac.- This investigation is primarily for staging bone involvement and cannot guide acute management of neurological compromise.*PET-CT scan*- PET-CT is an advanced imaging modality used for cancer staging and detecting **metabolically active lesions** but is not the appropriate immediate investigation for suspected spinal cord compression.- It is a lengthy procedure and lacks the necessary **spatial resolution** of an MRI to precisely evaluate direct spinal cord compromise in an emergency setting.

Question 241: A 29-year-old professional rugby player presents with acute lower back pain following a tackle 3 days ago. He describes sharp pain radiating down his right leg to the lateral aspect of his foot. On examination, he has weakness of foot eversion, reduced sensation over the dorsum of the foot, and an absent ankle reflex. Straight leg raise is positive at 40 degrees on the right. Which nerve root is most likely affected?

A. L3
B. L4
C. L5
D. S1 (Correct Answer)
E. S2

Explanation: ***S1*** - The patient's presentation of **sharp pain radiating to the lateral aspect of the foot**, **weakness of foot eversion**, and an **absent ankle reflex** are classic signs of S1 radiculopathy. - S1 nerve root compression specifically impairs the **gastrocnemius and soleus muscles** (leading to loss of ankle reflex) and the **peroneal muscles** (causing weakness in foot eversion). *L3* - L3 radiculopathy typically involves pain and sensory changes in the **anterior thigh** and **medial knee**. - Motor weakness affects **hip flexion** and **knee extension**, often with a diminished or absent **patellar reflex**, which is not observed here. *L4* - L4 nerve root compression presents with pain and sensory loss over the **medial leg** and ankle, and weakness in **knee extension**. - The distinguishing reflex finding for L4 is a reduced or **absent patellar reflex**, contrasting with the absent ankle reflex in this case. *L5* - L5 radiculopathy primarily causes weakness in **foot dorsiflexion** and **great toe extension**, with sensory loss usually in the **first web space** and mid-dorsum of the foot. - A key differentiator is that the **ankle reflex remains intact** in L5 lesions, which contradicts the patient's absent ankle reflex. *S2* - S2 nerve root involvement is less common and typically presents with pain or sensory disturbance in the **posterior thigh** and **perianal region**. - Motor deficits are usually associated with **plantarflexion** and intrinsic foot muscles, but without the specific constellation of symptoms pointing to S1 involvement.

Question 242: An 81-year-old woman presents 48 hours after a fall with a displaced intracapsular neck of femur fracture. She has a history of Parkinson's disease and takes levodopa. Her pre-admission mobility was limited to indoor walking with a frame. Which surgical intervention offers the best balance of functional outcome and surgical morbidity?

A. Total hip replacement
B. Hemiarthroplasty (Correct Answer)
C. Dynamic hip screw
D. Proximal femoral nail
E. Cannulated screw fixation

Explanation: ***Hemiarthroplasty*** - For elderly patients with **limited mobility** (indoor walking with a frame) and comorbidities like **Parkinson's disease**, hemiarthroplasty provides good pain relief with lower **surgical morbidity**. - It is the treatment of choice in **displaced intracapsular fractures** for low-demand patients, allowing immediate **weight-bearing** and having a lower risk of **dislocation** compared to total hip replacement, especially in patients with neuromuscular disorders. *Total hip replacement* - While offering better long-term functional results, it is generally reserved for more active patients (independent outdoors) without significant **cognitive impairment**. - This patient's limited indoor mobility and increased **neuromuscular instability** from Parkinson’s disease significantly elevate the risk of postoperative **dislocation** and poorer functional outcomes. *Dynamic hip screw* - This device is primarily indicated for **extracapsular hip fractures**, such as **intertrochanteric fractures**, rather than intracapsular ones. - In displaced intracapsular fractures, a dynamic hip screw carries a high risk of **non-union** and **avascular necrosis** due to compromised blood supply to the femoral head. *Proximal femoral nail* - This intramedullary device is indicated for **subtrochanteric fractures** or complex unstable **extracapsular fractures**. - It is not used for **intracapsular fractures**, as it does not adequately address the high risk of **femoral head osteonecrosis** inherent in these injuries. *Cannulated screw fixation* - This method is usually reserved for **undisplaced or impacted** intracapsular fractures (Garden I and II) to preserve the native femoral head. - In **displaced fractures** (Garden III and IV) in an 81-year-old, the risk of **failure of fixation** and subsequent **avascular necrosis** is unacceptably high, making arthroplasty a more appropriate solution.

Question 243: A 43-year-old woman presents with a 6-month history of lower back pain radiating to both legs, worse on standing and walking, relieved by sitting or leaning forward. She describes difficulty walking up hills but can cycle without problems. Neurological examination reveals preserved reflexes and no sensory deficit. What is the most likely diagnosis?

A. Lumbar disc prolapse with bilateral nerve root compression
B. Cauda equina syndrome
C. Lumbar spinal stenosis (Correct Answer)
D. Ankylosing spondylitis
E. Peripheral vascular disease

Explanation: ***Lumbar spinal stenosis***- Characterized by **neurogenic claudication**, where leg pain is exacerbated by walking or standing and relieved by **spinal flexion** (sitting or leaning forward).- The ability to **cycle without problems** (the "shopping cart sign") is classic because flexion increases the cross-sectional area of the spinal canal, relieving pressure on neural elements.*Lumbar disc prolapse with bilateral nerve root compression*- Typically presents with **acute onset** radicular pain and often demonstrates **positive straight leg raise** or other nerve root tension signs.- Symptoms are usually **unilateral** or asymmetrical, and are often worsened by flexion (sitting), which is the opposite of this patient's presentation.*Cauda equina syndrome*- A surgical emergency presenting with **saddle anesthesia**, bladder or bowel dysfunction, and **decreased anal tone**.- This patient lacks the significant neurological deficits and acute **sphincter dysfunction** characteristic of this syndrome.*Ankylosing spondylitis*- Presents as **inflammatory back pain** that is typically worse at rest or in the morning and **improves with exercise**.- It primarily affects the **sacroiliac joints** and is associated with significant morning stiffness, unlike the activity-induced pain seen here.*Peripheral vascular disease*- Causes **vascular claudication**, where pain is strictly related to exertion and is relieved simply by **standing still**.- Unlike spinal stenosis, it is not affected by **spinal posture** (leaning forward) and is usually accompanied by **diminished peripheral pulses**.

Question 244: A 75-year-old man undergoes internal fixation with cannulated screws for an undisplaced intracapsular neck of femur fracture. Six months post-operatively, he develops increasing hip pain and difficulty mobilising. Radiographs show segmental collapse of the femoral head with a crescent sign. What is the underlying pathophysiological mechanism?

A. Non-union of the fracture due to inadequate fixation
B. Avascular necrosis of the femoral head secondary to disrupted blood supply (Correct Answer)
C. Septic arthritis from surgical site infection
D. Osteoarthritis secondary to altered hip biomechanics
E. Heterotopic ossification causing restricted movement

Explanation: ***Avascular necrosis of the femoral head secondary to disrupted blood supply*** - The **crescent sign** (subchondral lucency) and **segmental collapse** of the femoral head are characteristic radiological findings for **avascular necrosis (AVN)**, typically occurring months after injury. - Intracapsular neck of femur fractures, even if undisplaced, frequently disrupt the **medial circumflex femoral artery** and its retinacular branches, leading to ischemia and eventual bone death. *Non-union of the fracture due to inadequate fixation* - This condition would typically present with persistent pain at the fracture site, possibly with visible **fracture line** on radiographs, or signs of **hardware failure** (e.g., screw loosening or cut-out). - While non-union causes pain and difficulty mobilising, it does not specifically manifest as **segmental collapse** or a **crescent sign** in the femoral head itself. *Septic arthritis from surgical site infection* - Septic arthritis presents more acutely with severe pain, **fever**, warmth, and often a marked inability to bear weight due to significant **joint effusion** and inflammation. - Radiographically, it typically shows rapid **joint space narrowing** and destruction of articular cartilage, rather than isolated subchondral collapse. *Osteoarthritis secondary to altered hip biomechanics* - Post-traumatic osteoarthritis is a chronic, degenerative process that develops over years, not typically within six months, and is characterized by **osteophytes**, **joint space narrowing**, and subchondral sclerosis. - It lacks the specific radiological feature of a **crescent sign** and the acute segmental collapse associated with AVN. *Heterotopic ossification causing restricted movement* - This involves the formation of **ectopic bone** in the soft tissues surrounding the joint, which can cause pain and severe restriction of movement. - Radiographs would show discrete **radiopaque masses** outside the bone, not the collapse or crescent sign within the femoral head itself.

Question 245: A 52-year-old man with a history of chronic lower back pain presents with new onset bilateral leg weakness, saddle anaesthesia, and urinary retention over the past 8 hours. On examination, he has reduced anal tone and bilateral absent ankle reflexes. What is the most appropriate immediate management?

A. Urgent MRI spine and neurosurgical referral for emergency decompression (Correct Answer)
B. Commence high-dose oral prednisolone and arrange outpatient MRI
C. Admit for bed rest, analgesia, and physiotherapy review
D. Arrange urgent CT lumbar spine and refer to spinal team within 24 hours
E. Prescribe gabapentin and refer to chronic pain clinic

Explanation: ***Urgent MRI spine and neurosurgical referral for emergency decompression***- The patient presents with classic signs of **Cauda Equina Syndrome (CES)**, including **saddle anesthesia**, **urinary retention**, and **reduced anal tone**, which necessitates immediate intervention.- An **urgent MRI spine** is the gold standard for definitive diagnosis, and **emergency surgical decompression** is crucial within hours to prevent permanent neurological deficits like bladder and bowel dysfunction.*Commence high-dose oral prednisolone and arrange outpatient MRI*- **High-dose oral prednisolone** is primarily used for inflammatory conditions or metastatic spinal cord compression, not as the primary treatment for mechanical compression in CES.- Arranging an **outpatient MRI** is dangerously delayed; CES is a time-sensitive emergency where delayed diagnosis and treatment lead to irreversible neurological damage.*Admit for bed rest, analgesia, and physiotherapy review*- While **bed rest** and **analgesia** provide symptomatic relief, they do not address the underlying **spinal cord or nerve root compression** that defines CES.- **Physiotherapy** is inappropriate for an acute neurosurgical emergency and cannot resolve the mechanical compression causing the severe neurological deficits.*Arrange urgent CT lumbar spine and refer to spinal team within 24 hours*- An **urgent CT lumbar spine** can show bony pathology but is inferior to **MRI** for visualizing soft tissues like discs, ligaments, and the cauda equina nerve roots.- While urgent, a **24-hour referral** might be too long given the rapid progression and time-critical nature of CES, where outcomes are better with earlier decompression.*Prescribe gabapentin and refer to chronic pain clinic*- **Gabapentin** is used for neuropathic pain management, which addresses a symptom but not the root cause of acute neurological compression.- Referring to a **chronic pain clinic** is inappropriate for an acute, rapidly evolving neurological emergency like CES, which requires immediate specialist intervention.

Question 246: An 85-year-old woman with advanced dementia sustains an undisplaced intracapsular neck of femur fracture following a fall in her care home. She was independently mobile with a frame prior to the fall. Her past medical history includes atrial fibrillation, hypertension, and osteoporosis. What is the most appropriate definitive management?

A. Dynamic hip screw fixation
B. Total hip replacement
C. Hemiarthroplasty
D. Cannulated hip screw fixation (Correct Answer)
E. Conservative management with analgesia and early mobilisation

Explanation: ***Cannulated hip screw fixation*** - For **undisplaced intracapsular** hip fractures, internal fixation with **cannulated screws** is the standard treatment to preserve the femoral head and minimize surgical morbidity. - Despite the patient's advanced dementia, her **pre-morbid mobility** (walking with a frame) warrants surgical fixation to facilitate early mobilization and prevent complications of bed rest. *Dynamic hip screw fixation* - This approach is the gold standard for **extracapsular** (intertrochanteric) fractures, rather than intracapsular fractures. - Using it for an undisplaced intracapsular fracture would involve unnecessary extensive surgical exposure and bone removal compared to **cannulated screws**. *Total hip replacement* - Typically reserved for fit, active patients with **displaced intracapsular** fractures who meet specific criteria like walking independently out-of-doors. - Is contraindicated here due to the patient's **advanced dementia**, which significantly increases the risk of post-operative **dislocation** and necessitates a simpler procedure. *Hemiarthroplasty* - This is the preferred treatment for **displaced intracapsular** fractures in patients with limited functional demands or cognitive impairment. - Since the fracture is **undisplaced**, internal fixation is preferred as it is less invasive and carries a lower risk of infection than joint replacement. *Conservative management with analgesia and early mobilisation* - This is usually reserved only for patients who are **medically unfit** for any anesthesia or are in the very final stages of terminal illness. - It is associated with high rates of **non-union**, chronic pain, and fatal complications like **pressure sores** and pulmonary embolism due to prolonged immobility.

Question 247: A 38-year-old woman presents to her GP with a 3-week history of lower back pain that is worse at night and in the morning, with significant stiffness lasting over an hour. She reports improvement with exercise. She has no history of trauma. Her inflammatory markers are elevated (CRP 45 mg/L, ESR 38 mm/hr). Which investigation would be most appropriate to confirm the underlying diagnosis?

A. MRI lumbar spine (Correct Answer)
B. Plain radiographs of sacroiliac joints
C. HLA-B27 typing
D. Bone density scan (DEXA)
E. CT lumbar spine

Explanation: ***MRI lumbar spine***- In patients with suspected **axial spondyloarthropathy**, MRI is the most sensitive imaging modality as it can detect **bone marrow oedema** and early **sacroiliitis** before structural changes occur.- The clinical presentation of **inflammatory back pain** (night pain, prolonged morning stiffness, and improvement with exercise) warrants MRI when plain films are normal or to confirm early-stage disease.*Plain radiographs of sacroiliac joints*- While often used as a first-line test, radiographs can be normal in early disease as **structural changes** like erosions and fusion take years to develop.- A normal X-ray does not rule out **non-radiographic axial spondyloarthropathy**, making it less sensitive for early diagnosis compared to MRI.*HLA-B27 typing*- The **HLA-B27** allele is highly associated with ankylosing spondylitis but is not diagnostic because it is present in approximately 8% of the healthy population.- It acts as a supportive marker rather than a confirmatory investigation to objectively identify the **inflammatory changes** in the spine.*Bone density scan (DEXA)*- A **DEXA scan** is used to evaluate bone mineral density for conditions like **osteoporosis**, which presents differently than inflammatory arthropathy.- While patients with chronic axial spondyloarthropathy are at increased risk of spinal **osteoporosis**, this test cannot confirm the primary diagnosis of the inflammatory condition.*CT lumbar spine*- CT provides excellent detail of **bony anatomy** and chronic erosions but is inferior to MRI for visualizing **active inflammation**.- It involves significant **radiation exposure** and lacks the soft-tissue contrast required to detect marrow oedema associated with early-stage disease.

Question 248: A 70-year-old woman presents to the Emergency Department after slipping on ice. She complains of right hip pain and is unable to weight-bear. On examination, her right leg is shortened and externally rotated. Radiographs confirm a subcapital neck of femur fracture. Which anatomical structure is most at risk of damage in this type of fracture, potentially leading to avascular necrosis?

A. Obturator artery
B. Medial circumflex femoral artery (Correct Answer)
C. Lateral circumflex femoral artery
D. Profunda femoris artery
E. Inferior gluteal artery

Explanation: ***Medial circumflex femoral artery***- This artery is the **primary blood supply** to the femoral head in adults, providing 60-80% of its vasculature via the **retinacular vessels** along the femoral neck.- In **intracapsular fractures** like a subcapital fracture, these delicate vessels are frequently disrupted, leading to a high risk of **avascular necrosis (AVN)** of the femoral head.*Obturator artery*- The obturator artery provides blood to the femoral head via the **artery of the ligamentum teres**, which is a minor contributor in adults.- This vessel is usually insufficient to maintain **viability of the femoral head** if the primary circumflex arteries are damaged.*Lateral circumflex femoral artery*- This artery primarily supplies the **greater trochanter** and the anterior/lateral thigh muscles, not the femoral head itself.- It contributes significantly less to the **proximal femoral epiphysis** compared to its medial counterpart.*Profunda femoris artery*- This is the large **deep artery of the thigh** that serves as the parent vessel for both the medial and lateral circumflex femoral arteries.- While it is the source, it is not the specific anatomical structure directly ruptured at the level of the **subcapital femoral neck** leading to AVN.*Inferior gluteal artery*- This artery primarily supplies the **gluteus maximus muscle** and contributes to the **cruciate anastomosis** of the hip.- It does not provide significant direct perfusion to the **femoral head**, making it irrelevant to the development of AVN in neck fractures.

Question 249: A 76-year-old woman undergoes a cemented hemiarthroplasty for a displaced intracapsular neck of femur fracture under spinal anaesthesia. During cementation and prosthesis insertion, she suddenly becomes hypotensive (BP 75/40 mmHg) with oxygen desaturation (SpO₂ 85% on 4L oxygen) and develops an altered level of consciousness. The anaesthetist notes increased airway pressures and the patient becomes difficult to ventilate. What is the most likely intraoperative complication?

A. Fat embolism syndrome
B. Pulmonary embolism from DVT
C. Acute myocardial infarction
D. Bone cement implantation syndrome (Correct Answer)
E. Anaphylactic reaction to antibiotic prophylaxis

Explanation: ***Bone cement implantation syndrome***- This syndrome is characterized by **hypoxia**, **hypotension**, and cardiac instability specifically occurring during or shortly after the **cementation** and insertion of the prosthesis.- It results from the **embolization** of bone marrow, fat, and cement debris into the pulmonary circulation, causing a sudden increase in **pulmonary vascular resistance** and increased airway pressures.*Fat embolism syndrome*- Typically presents **24-72 hours** after an injury or surgery, rather than an acute intraoperative event during cementation.- It is characterized by a classic triad of **respiratory distress**, **neurological symptoms**, and a **petechial rash**, which aren't the primary findings here.*Pulmonary embolism from DVT*- While possible in elderly immobile patients, it is less likely to coincide exactly with the **moment of cementation**.- Intraoperative PE usually presents with sudden **hypocapnia** and cardiovascular collapse but lacks the specific association with **cement-related intramedullary pressure** changes.*Acute myocardial infarction*- Although a patient of this age may have cardiac risk, a sudden MI wouldn't typically cause an increase in **airway pressures**.- The temporal relationship with **prosthesis insertion** and cement use strongly points toward a mechanical/embolic cause rather than primary ischemia.*Anaphylactic reaction to antibiotic prophylaxis*- Anaphylaxis occurs shortly after **drug administration** (e.g., at induction), whereas this event is precisely timed with **orthopedic cementation**.- While it causes hypotension and high airway pressures (bronchospasm), it does not explain the mechanical **pulmonary embolic** nature of the desaturation as well as BCIS.

Question 250: A 50-year-old man presents with a 2-week history of acute severe lower back pain following heavy lifting. The pain radiates down both legs and he reports difficulty passing urine with reduced sensation around his perineum. On examination, he has bilateral leg weakness, reduced anal tone, and absent bulbocavernosus reflex. What is the timeframe within which surgical decompression should ideally be performed to optimize neurological recovery?

A. Within 6 hours of symptom onset
B. Within 24 hours of symptom onset
C. Within 48 hours of symptom onset (Correct Answer)
D. Within 72 hours of symptom onset
E. Within 1 week of symptom onset

Explanation: ***Within 48 hours of symptom onset***- For patients with **Cauda Equina Syndrome (CES)**, performing surgical decompression within **48 hours** is the generally accepted clinical threshold for optimizing bladder, bowel, and sexual function recovery.- While the patient has already been symptomatic for 2 weeks, the standard academic teaching identifies the **48-hour window** as the critical timeframe for emergency intervention to prevent permanent neurological deficits.*Within 6 hours of symptom onset*- Although faster intervention is always preferred in surgical emergencies, a **6-hour target** is not the standard benchmark used in clinical literature or guidelines for CES recovery.- Attempting to meet a 6-hour window is often logistically impossible due to the time required for **urgent MRI confirmation** and surgical preparation.*Within 24 hours of symptom onset*- Some studies suggest that surgery within **24 hours** (CES-incomplete) may offer superior outcomes compared to later surgery, but it is not the widely established "ideal threshold" for general exam purposes.- The **48-hour mark** remains the most significant prognostic divider cited in major meta-analyses regarding **neurological recovery**.*Within 72 hours of symptom onset*- Performing surgery at **72 hours** is associated with a significantly higher risk of **permanent saddle anesthesia** and chronic urinary incontinence.- This timeframe is considered a **delay in treatment** and is often linked to poor medical-legal outcomes and irreversible nerve root damage.*Within 1 week of symptom onset*- Waiting **one week** is clinically inappropriate for an acute presentation, as the risk of **permanent motor paralysis** and autonomic dysfunction becomes extremely high.- Even if a patient presents late (as in this case), surgery is still performed urgently to salvage remaining function, but it is far beyond the **ideal recovery window**.

Question 251: A 69-year-old woman with multiple comorbidities including chronic kidney disease stage 4 sustains a displaced intracapsular neck of femur fracture. Pre-injury, she was mobile with a walking frame indoors only and had moderate dementia. Her abbreviated mental test score is 5/10. Regarding her surgical management, which procedure is most appropriate?

A. Total hip replacement using an uncemented prosthesis
B. Cemented hemiarthroplasty (Correct Answer)
C. Uncemented hemiarthroplasty
D. Total hip replacement using a cemented prosthesis
E. Dynamic hip screw fixation

Explanation: ***Cemented hemiarthroplasty*** - **Cemented hemiarthroplasty** is the treatment of choice for patients with **displaced intracapsular** hip fractures who have low mobility needs, cognitive impairment (**AMTS < 8/10**), or significant comorbidities. - Using **bone cement** provides immediate stable fixation, leads to better post-operative pain relief, and is associated with lower rates of **periprosthetic fracture** compared to uncemented options. *Total hip replacement using an uncemented prosthesis* - **Total hip replacement (THR)** is reserved for patients who were pre-operatively mobile with no more than one stick, have no **cognitive impairment**, and are medically fit for a longer procedure. - Uncemented prostheses are generally avoided in the elderly as they carry a higher risk of **intra-operative fracture** and poor biological integration due to osteoporotic bone. *Uncemented hemiarthroplasty* - **NICE guidelines** recommend against using uncemented implants in hip fracture surgery because they are associated with increased long-term **thigh pain** and failure rates. - While it avoids the risk of **Bone Cement Implantation Syndrome (BCIS)**, the mechanical stability in osteoporotic bone is significantly inferior to **cemented fixation**. *Total hip replacement using a cemented prosthesis* - Although cemented fixation is preferred, a **Total Hip Replacement** is not indicated here because the patient is not a "high-demand" walker and has **dementia**, which increases the risk of post-operative **dislocation**. - THR is more appropriate for patients who are fully independent, expected to live more than 5 years, and lack significant **cognitive impairment**. *Dynamic hip screw fixation* - A **Dynamic Hip Screw (DHS)** is typically the standard treatment for **extracapsular** (intertrochanteric) fractures, not displaced intracapsular fractures. - In **displaced intracapsular fractures**, internal fixation has an unacceptably high risk of failure due to **avascular necrosis** and non-union of the femoral head.

Question 252: A 42-year-old office worker presents with chronic lower back pain and left leg pain for 8 months. He has tried physiotherapy and analgesia with limited benefit. MRI shows a large L4/L5 disc prolapse with nerve root compression. He has no red flag symptoms and neurological examination reveals mild L5 weakness (4/5 ankle dorsiflexion) but no cauda equina features. What is the most appropriate next step in management?

A. Urgent surgical decompression within 48 hours
B. Epidural steroid injection
C. Continue conservative management for another 6 months
D. Referral to spinal surgery for consideration of microdiscectomy (Correct Answer)
E. Commence oral corticosteroids

Explanation: ***Referral to spinal surgery for consideration of microdiscectomy***- In a patient with **chronic radiculopathy** (8 months) who has failed **conservative management** (physiotherapy, analgesia) and has an **MRI-confirmed large disc prolapse** with **nerve root compression**, surgical referral is indicated.- The presence of **objective neurological deficit** (mild L5 weakness, 4/5 ankle dorsiflexion) further supports the need for surgical assessment to prevent permanent nerve root damage and improve long-term outcomes.*Urgent surgical decompression within 48 hours*- This is typically reserved for **Cauda Equina Syndrome** or rapidly **progressive severe neurological deficits**, which are absent in this case.- The patient specifically has **no red flag symptoms** and no features of cauda equina syndrome, negating the need for emergency surgery.*Epidural steroid injection*- While epidural steroid injections can offer **temporary pain relief** for radiculopathy, they do not address the underlying mechanical compression.- Given the **chronicity of symptoms** (8 months), failure of conservative measures, and **objective motor weakness**, an injection is unlikely to be a definitive solution and may only delay more effective treatment.*Continue conservative management for another 6 months*- The patient has already undergone 8 months of **conservative management** with limited benefit, indicating its ineffectiveness for this chronic condition.- Further delaying definitive treatment increases the risk of **chronic pain syndromes** and potentially irreversible neurological deficits due to prolonged nerve compression.*Commence oral corticosteroids*- **Oral corticosteroids** have limited evidence for significant long-term benefit in treating **chronic radiculopathy** caused by mechanical disc prolapse.- They do not resolve the **mechanical compression** on the nerve root and are not considered a primary or definitive treatment for persistent symptoms with objective weakness after extensive failed conservative care.

Question 253: A 72-year-old man presents following a mechanical fall. Radiographs show an undisplaced intracapsular neck of femur fracture (Garden II). He is medically fit with no significant comorbidities and was independently mobile. He undergoes internal fixation with three cannulated screws. Six months post-operatively, he develops progressive groin pain and difficulty weight-bearing. Repeat radiographs show collapse of the femoral head with a crescent sign on the AP view. What is the most likely complication?

A. Non-union of the fracture
B. Surgical site infection
C. Avascular necrosis of the femoral head (Correct Answer)
D. Implant failure with screw loosening
E. Osteoarthritis of the hip joint

Explanation: ***Avascular necrosis of the femoral head*** - The development of progressive groin pain, difficulty weight-bearing, **collapse of the femoral head**, and a **crescent sign** on radiographs six months post-op are pathognomonic for **avascular necrosis (AVN)**. The crescent sign indicates a subchondral fracture due to necrotic bone. - **Intracapsular neck of femur fractures**, even when undisplaced (Garden II), are highly susceptible to AVN due to the compromise of the **medial circumflex femoral artery**, which is the primary blood supply to the femoral head. *Non-union of the fracture* - **Non-union** would typically present with persistent pain and instability, but radiographs would show a persistent **fracture line** with absent callus formation, not the specific **femoral head collapse** or **crescent sign** seen here. - While it causes ongoing pain and difficulty weight-bearing, its radiographic appearance is distinct from that of AVN. *Surgical site infection* - A **surgical site infection** would usually manifest earlier with signs such as **fever**, local **erythema**, **swelling**, and possibly purulent drainage, which are not described in this case. - Radiographic features of infection are typically **periosteal reaction** or osteomyelitis-related changes, not **femoral head collapse** with a **crescent sign**. *Implant failure with screw loosening* - **Implant failure** or **screw loosening** would be characterized by specific radiographic findings like **radiolucencies around the screws**, screw migration, or breakage of the hardware components. - While these can cause pain and mechanical issues, they do not directly account for the **collapse of the femoral head** and the **crescent sign**, which point to a primary bone pathology. *Osteoarthritis of the hip joint* - **Post-traumatic osteoarthritis** is a chronic condition that typically develops over a longer period, characterized by **joint space narrowing**, **osteophytes**, and **subchondral sclerosis**. - At six months, the specific signs of **femoral head collapse** and a **crescent sign** are indicative of AVN, which is a precursor or an acute event distinct from chronic degenerative changes of osteoarthritis.

Question 254: A 35-year-old man with known intravenous drug use presents with severe lower back pain, fever of 39.2°C, and difficulty mobilizing. He has been unwell for 5 days with rigors. On examination, he has marked tenderness over the L3-L4 region. Neurological examination reveals normal power, sensation, and reflexes in both lower limbs. His blood tests show WCC 18 × 10⁹/L and CRP 285 mg/L. What is the most appropriate immediate investigation?

A. Plain radiographs of lumbar spine
B. CT lumbar spine with contrast
C. MRI whole spine with gadolinium contrast (Correct Answer)
D. Bone scintigraphy
E. Lumbar spine ultrasound

Explanation: ***MRI whole spine with gadolinium contrast***- **MRI with gadolinium** is the gold-standard investigation for suspected **spinal infection** (discitis/osteomyelitis), offering 96% sensitivity for early detections within days.- **Whole spine** imaging is essential as infection can be **multifocal**, and it effectively evaluates for complications like **epidural abscess** or spinal cord compression.*Plain radiographs of lumbar spine*- X-rays have very low sensitivity in the early stages of infection, as **bony destruction** is often not visible until 2–4 weeks after the onset of symptoms.- They cannot reliably identify **soft tissue collections** or clarify the involvement of the intervertebral discs.*CT lumbar spine with contrast*- CT is less sensitive than MRI for detecting early **bone marrow edema** and inflammatory changes in the **epidural space**.- While useful for guiding **biopsies**, it provides inferior visualization of the neural structures compared to MRI.*Bone scintigraphy*- **Technetium-99m bone scans** lack the anatomical detail required to distinguish between different types of inflammatory or degenerative spinal processes.- It has a high rate of **false positives** and cannot adequately assess for the presence of an **epidural abscess**.*Lumbar spine ultrasound*- Ultrasound cannot penetrate **bony structures** and is therefore ineffective for evaluating intra-spinal or vertebral body pathology.- It has no clinical role in the diagnostic workup for **vertebral osteomyelitis** or discitis.

Question 255: Which of the following blood vessels provides the primary blood supply to the femoral head that is most at risk in intracapsular neck of femur fractures?

A. Obturator artery
B. Profunda femoris artery
C. Medial circumflex femoral artery (Correct Answer)
D. Lateral circumflex femoral artery
E. Inferior gluteal artery

Explanation: ***Medial circumflex femoral artery***- The **medial circumflex femoral artery** is the primary source of blood supply to the **femoral head** in adults. Its **retinacular branches** ascend along the femoral neck, penetrating the joint capsule.- **Intracapsular neck of femur fractures** often disrupt these delicate retinacular vessels, particularly the posterior superior and inferior retinacular arteries, leading to a high risk of **avascular necrosis (AVN)** of the femoral head.*Obturator artery*- The **obturator artery** gives rise to the artery of the **ligamentum teres**, which supplies a small area of the femoral head, primarily in children.- In adults, this supply is typically **insufficient** to maintain the viability of the femoral head if the main circumflex vessels are compromised.*Profunda femoris artery*- The **profunda femoris artery** (deep femoral artery) is a major branch of the femoral artery, and it typically gives rise to the medial and lateral circumflex femoral arteries.- However, the profunda femoris itself does not directly supply the **femoral head**; its main role is to supply the adductor and hamstring muscles of the thigh.*Lateral circumflex femoral artery*- The **lateral circumflex femoral artery** contributes to the blood supply around the hip but primarily supplies the **greater trochanter** and the muscles of the lateral thigh.- While it forms part of the **extracapsular arterial ring**, its contribution to the direct arterial supply of the femoral head itself is significantly less than that of the medial circumflex femoral artery.*Inferior gluteal artery*- The **inferior gluteal artery** primarily supplies the **gluteus maximus muscle** and the posterior aspect of the hip joint.- It contributes to the **cruciate anastomosis** around the hip but is not a direct or primary blood supply to the **femoral head**.

Question 256: A 28-year-old woman presents to her GP with a 4-month history of lower back pain. She describes early morning stiffness lasting more than an hour that improves with exercise. She has occasional bilateral buttock pain. Blood tests reveal raised ESR and CRP. HLA-B27 is positive. Which feature would constitute a red flag requiring urgent investigation rather than being consistent with her likely inflammatory condition?

A. Morning stiffness lasting 90 minutes
B. Improvement with exercise
C. Bilateral buttock pain alternating sides
D. Progressive thoracic kyphosis with fever (Correct Answer)
E. Age under 45 years at symptom onset

Explanation: ***Progressive thoracic kyphosis with fever*** - While spinal deformity (like **kyphosis**) can develop in long-standing **Ankylosing Spondylitis**, the acute presence of **fever** is a significant **red flag**, suggesting a serious underlying issue such as **infection** (e.g., osteomyelitis, discitis, spinal tuberculosis) or **malignancy**. - **Fever** in the context of back pain, especially with progressive deformity, necessitates urgent investigation (e.g., MRI, blood cultures) to rule out conditions requiring immediate intervention and prevent potential **neurological compromise**. *Morning stiffness lasting 90 minutes* - Prolonged **morning stiffness** (typically >30 minutes, here 90 minutes) that improves with activity is a cardinal feature of **inflammatory back pain**, strongly suggestive of spondyloarthropathy. - This is a diagnostic criterion for inflammatory back pain and does not warrant urgent "red flag" protocols, but rather confirms the likely inflammatory condition. *Improvement with exercise* - A key characteristic differentiating **inflammatory back pain** from mechanical back pain is that symptoms **improve with exercise** and worsen with rest. - This finding supports a diagnosis of **spondyloarthropathy** and is a classic clinical indicator rather than an urgent warning sign. *Bilateral buttock pain alternating sides* - **Alternating buttock pain** is highly suggestive of **sacroiliitis**, reflecting inflammation within the sacroiliac joints common in **HLA-B27** positive patients. - This symptom is included in the **ASAS criteria** for inflammatory back pain and is considered a typical disease manifestation. *Age under 45 years at symptom onset* - Inflammatory spinal conditions typically present in **younger adults** (under the age of 45), which helps differentiate it from degenerative disc disease. - Onset at a younger age is a distinguishing feature consistent with inflammatory back pain, rather than a red flag for an alternative, urgent pathology.

Question 257: A 55-year-old woman sustains a basicervical neck of femur fracture following a fall. She is fit and active with no significant comorbidities. Radiographs confirm the fracture extends from the base of the femoral neck to the intertrochanteric region. What is the most appropriate surgical fixation method?

A. Cannulated hip screws
B. Dynamic hip screw with plate (Correct Answer)
C. Intramedullary femoral nail
D. Total hip replacement
E. Hemiarthroplasty

Explanation: ***Dynamic hip screw with plate*** - A **basicervical fracture** is an **extracapsular fracture** of the femoral neck, located at the junction with the intertrochanteric region, making the **Dynamic Hip Screw (DHS)** the gold standard for its stable fixation. - The DHS provides **stable compression** at the fracture site, which is crucial for promoting **secondary bone healing** in this well-vascularized region. *Cannulated hip screws* - These are primarily used for **intracapsular, undisplaced or minimally displaced** femoral neck fractures where rotational stability is paramount and blood supply is precarious. - They lack the necessary **biomechanical strength** and lateral support required to adequately stabilize an **extracapsular basicervical fracture**. *Intramedullary femoral nail* - Intramedullary nails are typically indicated for **unstable intertrochanteric**, subtrochanteric, or **reverse obliquity** fractures, offering superior load-sharing properties for these more complex patterns. - While an alternative, a DHS is generally considered sufficient and less invasive for a **stable basicervical fracture**, without demonstrating superior outcomes in this specific scenario. *Total hip replacement* - **Total hip replacement** is usually reserved for **displaced intracapsular femoral neck fractures** in active patients to minimize the risk of **avascular necrosis (AVN)** and allow early mobilization. - Basicervical fractures are **extracapsular** with a preserved blood supply, meaning they have a high potential for healing with internal fixation, making joint replacement unnecessary. *Hemiarthroplasty* - **Hemiarthroplasty** involves replacing only the femoral head and is commonly indicated for **displaced intracapsular femoral neck fractures** in elderly, less active patients. - It is inappropriate for **basicervical fractures** due to their excellent healing potential with internal fixation, as there is no need to sacrifice the native femoral head.

Question 258: A 68-year-old woman with rheumatoid arthritis presents with a 3-month history of progressive lower back pain and bilateral leg weakness. She reports difficulty walking and recent episodes of urinary incontinence. On examination, she has increased tone in both lower limbs with brisk knee reflexes, upgoing plantars bilaterally, and a sensory level at T10. What is the most likely diagnosis?

A. Cauda equina syndrome
B. Lumbar spinal stenosis
C. Thoracic cord compression (Correct Answer)
D. Diabetic amyotrophy
E. Polymyalgia rheumatica

Explanation: ***Thoracic cord compression***- The presence of **upper motor neuron (UMN) signs** (increased tone, brisk knee reflexes, and upgoing plantars) indicates a lesion above the conus medullaris, specifically affecting the spinal cord.- A **sensory level at T10** combined with urinary incontinence localizes the pathology to the thoracic spine, necessitating urgent MRI and neurosurgical evaluation.*Cauda equina syndrome*- This condition typically presents with **lower motor neuron (LMN) signs**, such as decreased reflexes and flaccid weakness, rather than UMN signs.- It is characterized by **saddle anesthesia** and absence of a trunk sensory level, which differentiates it from cord compression.*Lumbar spinal stenosis*- Usually presents with **neurogenic claudication**, where leg pain and weakness are triggered by walking and relieved by leaning forward.- It does not cause a clear **sensory level on the trunk** or UMN signs like positive Babinski (upgoing plantars).*Diabetic amyotrophy*- This is characterized by **asymmetric proximal muscle weakness** and severe pain, typically involving the quadriceps and hip flexors.- It lacks features of spinal cord involvement, such as a **sensory level**, urinary incontinence, or bilateral UMN signs.*Polymyalgia rheumatica*- Presents with symmetrical **proximal muscle pain and stiffness** in the shoulders and hips, often with an elevated ESR.- It is not a neurological condition and therefore does not cause **weakness, reflex changes, or sensory levels**.

Question 259: A 32-year-old builder presents with acute onset lower back pain after lifting heavy equipment. The pain radiates down the posterior aspect of his left leg to the heel. He describes sharp shooting pains and reports difficulty standing on tiptoe on the left foot. On examination, there is reduced sensation over the lateral border and sole of the left foot, and weakness of plantarflexion. The ankle jerk is diminished on the left. Which nerve root is most likely affected?

A. L3 nerve root
B. L4 nerve root
C. L5 nerve root
D. S1 nerve root (Correct Answer)
E. S2 nerve root

Explanation: ***S1 nerve root***- Compression of the **S1 nerve root** typically presents with weakness in **plantarflexion**, specifically causing difficulty with standing on **tiptoe** due to gastrocnemius and soleus involvement.- Physical findings include a **diminished ankle jerk** reflex and sensory loss localized to the **lateral border** and **sole of the foot**.*L3 nerve root*- **L3 radiculopathy** typically involves weakness in **hip flexion** and **knee extension** rather than foot movements.- Sensory loss is primarily found on the **anterior-medial thigh**, and it affects the **patellar (knee) reflex**.*L4 nerve root*- **L4 nerve root** involvement usually results in weakness of **knee extension** (quadriceps) and is characterized by an **absent knee jerk (patellar)** reflex.- Sensory deficits associated with **L4** are typically found along the **medial leg** and **medial malleolus**.*L5 nerve root*- **L5 radiculopathy** causes weakness in **big toe extension** (extensor hallucis longus) and **foot dorsiflexion**, leading to difficulty with **heel walking**.- Sensation is typically affected over the **dorsum of the foot** and the first web space, but the **ankle jerk** remains intact.*S2 nerve root*- **S2 compression** is rare as an isolated injury and usually involves sensory symptoms on the **posterior aspect of the thigh** and **perineum**.- It is more commonly associated with bladder/bowel dysfunction as part of **cauda equina syndrome** or pelvic plexopathy rather than specific ankle reflex changes.

Question 260: What is the classification system most commonly used to describe intracapsular neck of femur fractures based on the degree of displacement?

A. Weber classification
B. Garden classification (Correct Answer)
C. AO/OTA classification
D. Pauwels classification
E. Neer classification

Explanation: ***Garden classification*** - The **Garden classification** is the most widely used system for **intracapsular hip fractures**, categorizing them into four grades based on the degree of **displacement** observed on an AP radiograph. - This system is clinically crucial because it guides treatment; **Grades I and II** are considered undisplaced (stable), while **Grades III and IV** are displaced (unstable) with a higher risk of **avascular necrosis**. *Weber classification* - The **Weber classification** (specifically the Danis-Weber system) is used to describe **ankle fractures** based on the level of the fibular fracture relative to the **syndesmosis**. - It helps determine the stability of the ankle joint and the necessity of **surgical fixation**, but it is not applicable to femoral neck fractures. *AO/OTA classification* - The **AO/OTA classification** is a sophisticated, **alphanumeric system** designed to provide a universal language for all bone fractures throughout the body. - While it includes femoral neck fractures, its high complexity makes it less commonly used in daily clinical practice compared to the simpler **Garden system**. *Pauwels classification* - The **Pauwels classification** describes femoral neck fractures based on the **angle of the fracture line** relative to the horizontal plane to assess shear stress. - Although it helps predict the risk of **non-union**, it focuses on biomechanical stability rather than the degree of **displacement**. *Neer classification* - The **Neer classification** is the standard system used to describe fractures of the **proximal humerus**. - It categorizes fractures based on the number of **displaced segments** (parts) and the relationship between the anatomical neck, surgical neck, and tuberosities.

Question 261: An 82-year-old man undergoes a hemiarthroplasty for a displaced intracapsular neck of femur fracture. Post-operatively on day 1, he becomes acutely confused and agitated. His observations show: heart rate 110 bpm, blood pressure 95/60 mmHg, respiratory rate 24/min, oxygen saturations 91% on room air, temperature 37.8°C. His pain score is 8/10. What is the most appropriate immediate management priority?

A. Commence intravenous antibiotics for presumed surgical site infection
B. Request urgent CT head to exclude intracranial pathology
C. Optimize analgesia and assess for reversible causes of delirium (Correct Answer)
D. Start haloperidol for acute behavioural disturbance
E. Arrange urgent chest radiograph and commence treatment dose LMWH

Explanation: ***Optimize analgesia and assess for reversible causes of delirium***- Post-operative **delirium** is highly common in elderly patients following hip surgery. The patient's acute confusion and agitation, coupled with physiological derangements, strongly suggest this diagnosis.- A high **pain score (8/10)** is a significant precipitating factor for delirium. Addressing pain, along with other reversible causes like hypoxia, hypotension, and urinary retention, is the most appropriate immediate management priority. *Commence intravenous antibiotics for presumed surgical site infection*- While the patient has a low-grade fever, a **surgical site infection** (SSI) typically does not manifest locally or systemically with acute delirium on post-operative day 1.- Although **sepsis** is a concern, immediate empirical antibiotics should follow a thorough assessment for other potential infection sources (e.g., UTI, pneumonia) and stabilization of vital parameters.*Request urgent CT head to exclude intracranial pathology*- **Acute confusion** and agitation in an elderly post-surgical patient are statistically much more likely to be **delirium** due to metabolic or surgical stress than primary intracranial pathology.- A **CT head** is generally not indicated as a first-line investigation for delirium unless there are **focal neurological deficits** or a history of recent head trauma.*Start haloperidol for acute behavioural disturbance*- **Haloperidol** or other sedatives should be considered a last resort for acute agitation, primarily if the patient poses a **risk to themselves or others**.- Pharmacological interventions can mask the underlying cause of delirium, potentially worsen it, and carry side effects; **non-pharmacological interventions** and treating the primary physiological triggers are preferred.*Arrange urgent chest radiograph and commence treatment dose LMWH*- The patient's tachycardia, tachypnoea, and hypoxia are concerning and warrant investigation for **pulmonary embolism (PE)** or **pulmonary infection/atelectasis**; a chest radiograph is a reasonable step.- However, commencing **treatment-dose LMWH** empirically without diagnostic confirmation (e.g., CTPA) is risky in a post-operative patient due to the significant risk of **bleeding**.

Question 262: A 45-year-old office worker presents with a 6-week history of lower back pain radiating down his right leg to the lateral aspect of his foot. He reports numbness over the dorsum of his foot and difficulty walking on his heels. The pain is worse at night and he has noticed unintentional weight loss of 5 kg. On examination, he has reduced power in ankle dorsiflexion and an absent ankle jerk on the right. What is the most concerning feature suggesting serious underlying pathology?

A. Difficulty with heel walking
B. Night pain with weight loss (Correct Answer)
C. Radiation to the lateral foot
D. Absent ankle jerk reflex
E. Duration of symptoms for 6 weeks

Explanation: ***Night pain with weight loss*** - **Night pain** and **unintentional weight loss** are classic **red flag symptoms** that raise suspicion for **malignancy** or **spinal infection**. - While neurological signs indicate nerve compression, these systemic features necessitate urgent investigation with imaging and blood tests to rule out serious pathology. *Difficulty with heel walking* - This finding indicates weakness in **ankle dorsiflexion**, which is a sign of **L5 nerve root** compression. - Although it represents a motor deficit, it is a feature of **radiculopathy** and not a red flag for systemic disease or malignancy. *Radiation to the lateral foot* - Pain radiating down the leg to the lateral foot describes **sciatica**, specifically involving the **S1 dermatome**. - This is a common symptom of a **herniated disc** and does not inherently suggest a life-threatening or serious underlying disease. *Absent ankle jerk reflex* - An absent ankle jerk corresponds to an **S1 nerve root** lesion, often seen in mechanical lower back pathology. - While an objective clinical finding of **radiculopathy**, it is not considered a red flag compared to systemic constitutional symptoms. *Duration of symptoms for 6 weeks* - Chronic or subacute pain is common in mechanical back issues; red flags generally emphasize **severity** and **progression** rather than a 6-week duration alone. - A 6-week history is significant but less concerning than the **systemic features** of weight loss and non-mechanical night pain.

Question 263: A 78-year-old woman presents to the Emergency Department following a fall at home. She complains of severe left hip pain and is unable to weight-bear. On examination, her left leg is shortened, externally rotated, and abducted. An AP radiograph of the pelvis confirms a displaced intracapsular neck of femur fracture. Her past medical history includes hypertension and osteoarthritis. She was independently mobile prior to the fall. What is the most appropriate definitive surgical management?

A. Dynamic hip screw fixation
B. Total hip replacement
C. Cannulated screw fixation
D. Hemiarthroplasty (Correct Answer)
E. Intramedullary nail fixation

Explanation: ***Hemiarthroplasty*** - In elderly patients with a **displaced intracapsular** femoral neck fracture, hemiarthroplasty is the gold standard when there is a high risk of **avascular necrosis** due to disrupted blood supply. - It is preferred over internal fixation in patients over **65 years** to allow immediate weight-bearing and reduce the risk of secondary surgeries. *Dynamic hip screw fixation* - This is the treatment of choice for **extracapsular** fractures, specifically **intertrochanteric** fractures. - Using a DHS for a displaced intracapsular fracture in an elderly patient results in high rates of **non-union** and mechanical failure. *Total hip replacement* - While this patient was independently mobile, hemiarthroplasty is often the default choice in the very elderly unless they lead an exceptionally active lifestyle or have pre-existing **symptomatic** arthritis. - NICE guidelines recommend THR for displaced intracapsular fractures only if the patient can **walk independently** with no more than a stick, has no cognitive impairment, and is medically fit for anesthesia. *Cannulated screw fixation* - This method is typically reserved for **undisplaced** (Garden I and II) intracapsular fractures or displaced fractures in **young patients** (<60 years) to preserve the native femoral head. - In a 78-year-old with a displaced fracture, the risk of **vascular compromise** to the femoral head makes this fixation technique inappropriate. *Intramedullary nail fixation* - Intramedullary (IM) nails are primarily used for **subtrochanteric** fractures or unstable **intertrochanteric** fractures. - They do not address the primary pathology of an intracapsular fracture and are not indicated for **femoral neck** replacement or stabilization in this context.

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Orthopaedics & MSK — MCQs

Orthopaedics & MSK — MCQs

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