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Suspected grade 3 medial collateral ligament injury of the knee — MSRA MCQ

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ModerateSoft Tissue InjurySuspected grade 3 medial collateral ligament injury of the kneeMSRA

A 29-year-old amateur rugby player attends a GP-led urgent treatment centre 4 hours after a direct blow to the lateral aspect of his right knee while his foot was planted. He felt immediate medial knee pain and was unable to continue playing. He can now weight bear with a marked limp. There is medial joint-line and proximal medial tibial tenderness with a small effusion. The knee extends fully and there is no mechanical locking. Lachman and posterior drawer tests are negative. Varus stress testing is stable. Valgus stress testing demonstrates marked medial opening compared with the left knee at both 30 degrees of flexion and full extension, with no firm end point. Distal neurovascular examination is normal. Knee radiographs show no fracture or avulsion injury. What is the most appropriate management now?

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

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Correct answer: B — Arrange urgent referral to the knee service for assessment of associated ligamentous injury

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

This is a suspected grade 3 medial collateral ligament (MCL) injury: there is substantial valgus laxity without a firm end point. Crucially, laxity is present both at 30 degrees of flexion and in full extension. Valgus testing at these two positions is used to assess medial knee injury; opening in extension raises concern that injury is not a simple isolated low-grade MCL sprain and warrants assessment for associated medial or multiligament injury. UK NHS referral guidance advises that acute confirmed or suspected grade 3 MCL tears should be referred to the knee service for further assessment, with imaging considered within the specialist pathway. Therefore urgent knee-service referral is appropriate, alongside initial analgesia, protection and weight-bearing advice. A and B would be appropriate initial definitive pathways for uncomplicated grade 1 or 2 MCL injuries, which usually heal with rehabilitation. C is inappropriate because MRI should not delay referral and is generally arranged according to the specialist assessment pathway. D is excessive in this stable, neurovascularly intact patient with no fracture, dislocation, extensor mechanism failure or true locked knee; urgent outpatient specialist assessment is the proportionate escalation.

Reference: Ligament Tears/Sprains — NHS Tayside RefGuide (Reviewed 2025) — https://www.rightdecisions.scot.nhs.uk/nhs-tayside-refguide/surgery-and-orthopaedics/orthopaedic-and-trauma-surgery/knee/ligament-tearssprains/ The management of injuries to the medial side of the knee (2012) — https://pubmed.ncbi.nlm.nih.gov/22382986/