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Suspected combined ACL and high-grade MCL injury — MSRA MCQ

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HardKnee InjuriesSuspected combined ACL and high-grade MCL injuryMSRA

A 28-year-old semi-professional footballer presents to general practice 3 hours after a non-contact injury. While changing direction on a planted right foot, his knee collapsed into valgus and he felt a pop. He stopped playing immediately and developed a large swelling within 45 minutes. He can mobilise only with crutches and describes marked instability rather than locking. Examination shows a tense effusion. Lachman testing has a soft endpoint. There is marked medial joint opening with valgus stress at both 30° and full extension. He can perform a straight-leg raise. Plain radiographs obtained at an urgent treatment centre show no fracture. The foot is warm, with normal distal pulses, sensation and capillary refill. What is the most appropriate management today?

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Correct answer: D — Discuss the case with the on-call orthopaedic team for same-day urgent assessment

This injury requires same-day orthopaedic discussion. Rapid swelling after a pivoting injury indicates a haemarthrosis and therefore a significant intra-articular injury. A soft-endpoint Lachman test supports ACL rupture. Marked valgus laxity at both 30° and full extension indicates a high-grade medial-sided injury and raises concern for combined ligament injury rather than an isolated low-grade MCL sprain. The combination of rapid haemarthrosis and major instability is the decisive referral discriminator, even though radiographs are normal and there is currently no neurovascular deficit. Urgent MRI before referral is inappropriate because it may delay specialist assessment; imaging can be organised through the receiving orthopaedic pathway. Routine rehabilitation is appropriate initially for an uncomplicated ACL rupture or grade 1–2 MCL injury, but not for suspected combined/high-grade injury. An urgent outpatient knee-clinic referral is insufficient where there is acute haemarthrosis with instability. Review after swelling settles risks further instability episodes and delays assessment of injuries that may require early specialist management.

Reference: Ligament Tears/Sprains | NHS Tayside RefGuide (Date not stated; checked 15 August 2026) — https://www.rightdecisions.scot.nhs.uk/nhs-tayside-refguide/surgery-and-orthopaedics/orthopaedic-and-trauma-surgery/knee/ligament-tearssprains/