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Suspected knee fracture after acute trauma — MSRA MCQ

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HardKnee InjuriesSuspected knee fracture after acute traumaMSRA

A 55-year-old woman presents to a GP-led urgent treatment centre 90 minutes after tripping on a kerb and landing directly on the anterior aspect of her right knee. She has anterior knee pain and has not taken analgesia. She was able to walk four steps immediately after the fall and can do so now with a limp. She flexes the knee to 115 degrees. There is mild prepatellar swelling but no deformity, effusion, focal patellar tenderness, fibular-head tenderness, joint-line tenderness, ligamentous laxity or neurovascular deficit. She asks for an MRI because a colleague has suggested a meniscal injury. What is the most appropriate investigation today?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Arrange plain radiographs of the knee today

Plain knee radiographs should be arranged today. NICE recommends using the Ottawa knee rules to determine whether radiography is required in people aged over 2 years with suspected knee fracture. This patient has acute traumatic knee pain and meets an Ottawa criterion solely because she is aged 55 years or older. Her ability to bear weight, flex beyond 90 degrees, and absence of patellar or fibular-head tenderness do not negate that positive criterion. Urgent MRI is not first-line for excluding an acute bony injury and is not justified simply by concern about a meniscal injury without mechanical symptoms or examination findings. Ultrasound may identify superficial soft-tissue pathology but does not exclude an osseous knee injury. Conservative treatment without imaging would be appropriate only if no Ottawa criterion were present and clinical suspicion of fracture were sufficiently low. Direct fracture-clinic referral without initial radiography is not indicated because there is no deformity, inability to weight-bear, neurovascular compromise, gross instability or other feature requiring immediate specialist assessment.

Reference: NICE NG38: Fractures (non-complex): assessment and management — Use of clinical prediction rules for suspected knee fractures (Published 2016; last reviewed 23 June 2025) — https://www.nice.org.uk/guidance/ng38/chapter/recommendations Derivation of a decision rule for the use of radiography in acute knee injuries (1995) — https://pubmed.ncbi.nlm.nih.gov/7574120/