A 35-year-old motorcyclist presents with severe ankle pain and swelling. Radiographs show a transverse fracture of the medial malleolus. He also has marked tenderness over the proximal calf without obvious deformity there. The most appropriate next investigation is:

• A CT scan of the ankle joint
• B MRI of the ankle for syndesmotic assessment
• C Full length radiographs of the tibia and fibula including the knee ✓
• D Ankle brachial index measurement

Explanation

Medial malleolar fracture with proximal fibular tenderness suggests a Maisonneuve injury, an external rotation mechanism that disrupts the syndesmosis and interosseous membrane and fractures the proximal fibula. Standard ankle radiographs miss the fibular fracture, so full length tibiofibular films up to the knee are mandatory before classifying the injury as isolated. CT and MRI come later for surgical planning, and vascular studies are not indicated unless pulses are absent.

Reference: Rockwood and Green's Fractures in Adults, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.