Differentials
Lateral ankle ligament tear (anterior talofibular ligament and calcaneofibular ligament)
SIGNS / SYMPTOMS
Minimal lateral malleolar posterior bony tenderness. There may be a positive anterior drawer sign of the ankle or increased talar tilt depending on extent of the tear. Uncommonly there is significant deformity to the ankle.
INVESTIGATIONS
Plain radiographs will not identify a fracture.
MRI examination or musculoskeletal ultrasound may show edema with or without a tear to the lateral ankle ligaments (anterior talofibular ligament and calcaneofibular ligament).
Achilles tendon rupture
SIGNS / SYMPTOMS
No malleolar tenderness. There may be a gap in the Achilles tendon and a positive Thompson test.
INVESTIGATIONS
Plain radiographs demonstrate no fracture, and an MRI or musculoskeletal ultrasound of the Achilles tendon will demonstrate a tear.
Talar fracture
SIGNS / SYMPTOMS
There may be no malleolar tenderness. There may be a deformity to the ankle and hindfoot.
INVESTIGATIONS
Plain radiographs demonstrate a fracture of the talus.
Syndesmotic disruption
SIGNS / SYMPTOMS
There may be no malleolar tenderness. External rotation test and calf squeeze test may demonstrate pain in the syndesmosis.[38]
INVESTIGATIONS
Plain radiographs demonstrate no fracture but may show tibiofibular widening.
Use of this content is subject to our disclaimer