Orthopaedics & MSK — MCQs
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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?
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 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 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 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 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?
Which anatomical classification divides neck of femur fractures based on their relationship to the hip joint capsule and the intertrochanteric line?
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 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 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?
Orthopaedics & MSK UK Medical PG Practice Questions and MCQs
Question 161: 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 162: 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 163: 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 164: 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 165: 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 166: 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 167: 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 168: 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 169: 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 170: 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.
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