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Suspected syndesmotic ankle injury with an Ottawa-positive fracture screen — MSRA MCQ

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HardSoft Tissue InjurySuspected syndesmotic ankle injury with an Ottawa-positive fracture screenMSRA

A 34-year-old recreational basketball player is seen in a GP surgery 90 minutes after landing with his right foot planted and the ankle forced into dorsiflexion and external rotation. He felt immediate pain above the ankle joint and stopped playing. There is swelling centred over the distal tibiofibular region rather than the lateral ligaments. He has tenderness over the anterior inferior tibiofibular ligament and pain on calf squeeze. He also has focal bony tenderness at the posterior edge of the distal fibula. Despite analgesia, he was unable to take four steps immediately after the injury and remains unable to take four steps in the surgery. There is no deformity, and distal pulses, capillary refill and sensation are normal. What is the most appropriate management now?

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

Reveal the answer and explanation

Correct answer: E — Refer for same-day emergency assessment and ankle radiographs under the Ottawa ankle rules

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

This is not yet safely managed as an uncomplicated ankle sprain. The external-rotation/dorsiflexion mechanism, pain above the ankle mortise and positive calf-squeeze test suggest syndesmotic injury. However, the immediate priority is exclusion of fracture: he has malleolar-zone pain with posterior distal fibular bony tenderness and inability to bear weight for four steps both immediately and at assessment. Either criterion makes the Ottawa ankle rules positive, so same-day emergency assessment for plain radiographs is indicated. A is appropriate for a simple, clinically stable ankle sprain after fracture screening is negative, but would be premature here. B delays investigation despite an Ottawa-positive injury and suspected significant syndesmotic damage. C is tempting because MRI can define syndesmotic ligament injury, but MRI is not the first investigation when a fracture screen is positive; radiographs and acute trauma assessment come first. E similarly does not exclude fracture and ultrasound is not the appropriate first-line test in this acute presentation. Intact neurovascular findings and absence of deformity do not negate the need for radiography.

Reference: Patient history and differential diagnosis | Right Decisions, NHS Greater Glasgow and Clyde (Last reviewed 28 November 2025) — https://www.rightdecisions.scot.nhs.uk/ggc-msk-foot-and-ankle/initial-assessment/patient-history-and-differential-diagnosis/ A multifaceted strategy for implementation of the Ottawa ankle rules in two emergency departments (2009) — https://www.bmj.com/content/339/bmj.b3056