skip to main content

Acute lateral foot injury with suspected fifth-metatarsal fracture — MSRA MCQ

Instant feedback + full explanation. One question, done properly.

HardAnkle and FootAcute lateral foot injury with suspected fifth-metatarsal fractureMSRA

A 30-year-old recreational netball player attends a GP minor injuries service 3 hours after landing on another player's foot, with forced plantar flexion and inversion of her right foot. She was able to take 5 steps immediately after the injury and can take 4 steps in the clinic. Pain is maximal over the lateral midfoot. Examination shows focal bony tenderness at the base of the fifth metatarsal and mild anterior talofibular ligament tenderness. There is no tenderness at the navicular, the posterior edge or tip of either malleolus, or the proximal fibula. There is no deformity and neurovascular examination is normal. What is the most appropriate imaging investigation today?

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

Reveal the answer and explanation

Correct answer: C — Arrange plain radiographs of the foot

This patient meets the Ottawa foot-rule criteria for foot radiography: she has pain in the midfoot region with focal bony tenderness at the base of the fifth metatarsal. Her ability to bear weight does not negate this indication, because either relevant bony tenderness or inability to bear weight triggers imaging in the appropriate anatomical zone. She does not meet the ankle-rule criteria: there is no posterior malleolar edge or tip tenderness and she can walk 4 steps. Therefore, ankle radiographs are not indicated solely because the injury mechanism also commonly produces a lateral ligament sprain. Imaging both regions would add unnecessary ankle films. Treating without imaging would be appropriate only if the foot rule were negative, for example if tenderness were confined to the anterior talofibular ligament without fifth-metatarsal or navicular bony tenderness and she could weight-bear. Ultrasound is not the first-line test for excluding an acute fifth-metatarsal fracture in this presentation.

Reference: NICE NG38: Fractures (non-complex): assessment and management — recommendations (2016) — https://www.nice.org.uk/guidance/ng38/chapter/recommendations Evaluation of the Ottawa clinical decision rules for the use of radiography in acute ankle and midfoot injuries in the emergency department: an independent site assessment (1994) — https://pubmed.ncbi.nlm.nih.gov/7912053/