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Acute quadriceps tendon rupture — MSRA MCQ

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HardKnee InjuriesAcute quadriceps tendon ruptureMSRA

A 62-year-old man attends a GP-led urgent treatment centre 4 hours after missing the final step while descending stairs. His right knee flexed suddenly as he tried to prevent a fall. He felt an abrupt pain immediately above the patella and fell to the ground. He has type 2 diabetes and stage 3 chronic kidney disease. There is a large suprapatellar effusion and a palpable gap proximal to the patella. He cannot perform a straight-leg raise or actively extend the knee from 30 degrees of flexion, although passive extension is full. The patella lies lower than on the contralateral side. Plain radiographs show no fracture. Distal pulses, sensation and ankle movements are normal. What is the most appropriate management today?

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

Reveal the answer and explanation

Correct answer: C — Refer urgently to the orthopaedic on-call service for same-day assessment and operative repair

Explanation lettering: D = shown as C · E = shown as D · C = shown as E

This is an acute quadriceps tendon rupture. The decisive features are an eccentric quadriceps-loading mechanism in an older man with systemic risk factors, a palpable suprapatellar gap, patella baja, and—most importantly—loss of the extensor mechanism demonstrated by inability to perform a straight-leg raise or actively extend the knee. Full passive extension does not exclude tendon rupture; it distinguishes extensor mechanism failure from a fixed mechanical block. Plain radiographs may exclude an associated fracture but do not exclude quadriceps tendon rupture. Ultrasound can help when the diagnosis is uncertain, for example when pain, body habitus or swelling prevents adequate examination. Here, the clinical diagnosis is sufficiently secure and imaging must not delay definitive management. UK orthopaedic referral guidance states that quadriceps or patellar tendon rupture with inability to straight-leg raise and a palpable gap requires urgent orthopaedic referral for surgical repair. A is inappropriate because rehabilitation is important after repair, not as initial treatment for a complete extensor mechanism disruption. B and E would be reasonable only if the diagnosis were uncertain; neither is the priority in this presentation. C is inappropriate because routine referral risks delaying repair and restoration of knee extension.

Reference: Knee | NHS Tayside RefGuide (Checked 16 August 2026) — https://www.rightdecisions.scot.nhs.uk/nhs-tayside-refguide/surgery-and-orthopaedics/orthopaedic-and-trauma-surgery/knee/?UNLID=678850159202611919452