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Isolated posterior cruciate ligament tear with persistent instability after conservative rehabilitation — MSRA

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ModerateKnee InjuriesIsolated posterior cruciate ligament tear with persistent instability after conservative rehabilitationMSRA

A 32-year-old recreational cyclist re-attends general practice 14 weeks after striking the front of his flexed right knee against a car dashboard in a road-traffic collision. MRI arranged by the emergency department confirmed an isolated complete posterior cruciate ligament (PCL) tear, with no meniscal, anterior cruciate ligament, collateral ligament or posterolateral-corner injury. He has completed a supervised quadriceps-focused rehabilitation programme and has regained full knee movement and near-symmetrical quadriceps strength. However, he continues to report posterior knee pain when descending stairs and recurrent subjective instability when decelerating while running. Posterior drawer testing remains clearly positive compared with the contralateral side. There is no varus or valgus laxity, increased tibial external rotation, foot drop, sensory deficit, vascular compromise or mechanical locking. What is the most appropriate next step in management?

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Reveal the answer and explanation

Correct answer: A — Refer to orthopaedics for specialist review after failed conservative rehabilitation

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

This patient has an isolated PCL tear with persistent pain and functional instability despite more than 3 months of appropriate conservative rehabilitation. This meets the escalation threshold for orthopaedic review. The absence of varus laxity, increased external rotation, neurological deficit and vascular compromise makes a concomitant posterolateral-corner injury unlikely; therefore, urgent assessment for this is not indicated. A is inappropriate because this is not an acute combined ligament injury with severe instability requiring immediate surgical decision-making. B is unnecessary: the diagnosis and exclusion of important associated structural injuries have already been established on MRI, and the management-changing issue is failure of rehabilitation rather than diagnostic uncertainty. C would be reasonable earlier in the course because many isolated PCL injuries are managed non-operatively, but ongoing symptoms after 3 months warrant escalation. D would be appropriate if there were clinical features of posterolateral-corner injury, such as increased external rotation, varus opening or common peroneal nerve dysfunction. E appropriately balances initial non-operative management of isolated PCL injury with timely specialist assessment when pain or instability persists.

Reference: Ligament injuries | GGC MSK Index | Right Decisions (2024) — https://www.rightdecisions.scot.nhs.uk/ggc-msk-index/knee/ligament-injuries/ Ligament injuries | GGC MSK Index | Right Decisions (2024) — https://www.rightdecisions.scot.nhs.uk/ggc-msk-index/knee/ligament-injuries/