Orthopaedics & MSK — MCQs
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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?
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?
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 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 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 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 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 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 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 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?
Orthopaedics & MSK UK Medical PG Practice Questions and MCQs
Question 191: 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 192: 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 193: 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 194: 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 195: 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 196: 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 197: 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 198: 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 199: 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 200: 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.
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