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Acute complete patellar tendon rupture — MSRA MCQ

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ModerateKnee InjuriesAcute complete patellar tendon ruptureMSRA

A 38-year-old man attends a GP-led urgent treatment centre 90 minutes after landing awkwardly from a jump while playing basketball. His right knee flexed suddenly as he contracted his quadriceps forcefully. He felt a pop below the patella and fell immediately. He has marked anterior knee pain and swelling. He cannot actively extend the knee or perform a straight-leg raise, although passive extension is full. There is a palpable gap between the inferior pole of the patella and tibial tuberosity. The patella appears high-riding compared with the other side. Distal pulses, capillary refill, sensation and ankle movements are normal. Plain radiographs show no fracture. What is the most appropriate management today?

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

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Correct answer: A — Immobilise the knee in extension, provide analgesia and arrange same-day orthopaedic assessment

This presentation is of an acute complete patellar tendon rupture: the mechanism is forced knee flexion during powerful quadriceps contraction, and the decisive findings are loss of active knee extension and inability to perform a straight-leg raise. The palpable infrapatellar defect and patella alta further support disruption of the patellar tendon rather than an isolated ligament or meniscal injury. A normal radiograph does not exclude tendon rupture. Suspected acute patellar tendon rupture requires emergency orthopaedic referral. Initial management includes analgesia and protection of the extensor mechanism with the knee immobilised in extension while same-day assessment is arranged. Complete ruptures usually require operative repair; delay can increase tendon retraction and make repair more complex. A is inappropriate because physiotherapy is not initial management for a disrupted extensor mechanism. B and E may assist diagnostic clarification in uncertain or partial injuries, but imaging must not delay urgent referral when clinical features indicate complete rupture. C provides protection but routine review within 2 weeks is insufficient for a suspected acute tendon rupture requiring urgent orthopaedic assessment.

Reference: Primary Care – GPs: Physiotherapy Musculoskeletal (2023) — https://www.rightdecisions.scot.nhs.uk/media/2385/physiotherapy-musculoskeletal-june-short-version-20.pdf Acute Patellar Tendon Ruptures: An Update on Management (2024) — https://pubmed.ncbi.nlm.nih.gov/38569093/