A 30-year-old woman twists her ankle playing basketball. Ankle radiographs show no malleolar fracture, but there is widening of the medial clear space. Which additional radiograph must be obtained before concluding the injury is minor?
- A Oblique view of the hindfoot
- B Stress view in forced dorsiflexion
- C Full-length radiograph of the ipsilateral knee including the proximal fibula ✓
- D Contralateral ankle comparison views only
Correct answer: C. Full-length radiograph of the ipsilateral knee including the proximal fibula
Explanation
Medial clear space widening with no distal fibular fracture suggests a Maisonneuve injury: disruption of the deep deltoid ligament and syndesmosis with a proximal spiral fracture of the fibula transmitted through the interosseous membrane. Missing the proximal fibula fracture leads to inadequate treatment of an unstable syndesmotic injury. C full-length tibiofibular radiograph up to the knee is therefore mandatory whenever the medial clear space is widened without a distal fibula fracture.
Reference: Rockwood and Green's Fractures in Adults, 9th ed.
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Written and medically reviewed by the StethoPrep medical team.