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Stable isolated unimalleolar ankle fracture — MSRA MCQ

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HardAnkle and FootStable isolated unimalleolar ankle fractureMSRA

A 58-year-old woman attends a GP-led minor injuries unit 4 hours after an inversion injury to her left ankle while stepping off a kerb. She can take only 2 steps because of pain. There is swelling and focal bony tenderness over the lateral malleolus, but no medial malleolar tenderness, proximal fibular tenderness, skin break or neurovascular abnormality. Ankle radiographs show an undisplaced isolated fracture of the distal fibula involving the lateral malleolus. The ankle mortise is congruent, with no medial clear-space widening or talar shift. She has no peripheral neuropathy and can mobilise safely with crutches. 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 — Manage non-operatively with immediate unrestricted weight-bearing as tolerated, with review if symptoms are not improving by 6 weeks

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

This is an isolated, undisplaced unimalleolar fracture with a congruent mortise and no clinical or radiographic evidence of medial-sided injury or talar displacement. These features support a stable fracture suitable for non-operative management. NICE advises immediate unrestricted weight-bearing as tolerated for unimalleolar ankle fractures managed non-surgically, with advice to seek review if symptoms are not improving after 6 weeks. A and B are plausible because immobilisation and protected weight-bearing have historically been common practice. However, routine non-weight-bearing is unnecessary for a stable unimalleolar fracture and may delay functional recovery. D would be appropriate for an unstable ankle fracture, such as one with talar shift, mortise incongruity, associated medial or posterior malleolar injury, or another indication for fixation. E adds immobilisation and pharmacological VTE prophylaxis without a stated indication; the patient is not being managed in a rigid cast or kept non-weight-bearing. The key distinction is stability of the ankle mortise, not simply the presence of a fracture.

Reference: NICE NG38: Fractures (non-complex): assessment and management — Non-surgical orthopaedic management of unimalleolar ankle fractures (Published 2016; last reviewed 23 June 2025) — https://www.nice.org.uk/guidance/NG38/chapter/recommendations NICE NG38: Fractures (non-complex): assessment and management — Use of clinical prediction rules for suspected ankle fractures (Published 2016; last reviewed 23 June 2025) — https://www.nice.org.uk/guidance/ng38/chapter/recommendations