Ankle dislocation without accompanying malleolar fracture. A case report.

Dislocation of the tibiotalar joint without associated fracture is rare. We present here a 21-year-old man who sustained open posteromedial dislocation of the left ankle without malleolar facture when he jumped and sprained his right ankle while playing basketball. The most likely mechanism is forced flexion applied to the ankle joint leading to a rupture of the anterior capsule and lateral structures of the ankle followed by an accelerating inversion stress leading to a posteromedial dislocation of the talus from the tibial condyle. Transient paresthesia was noted in the area of the superficial peroneal nerve. At surgery, the anterior part of the tibiotalar joint capsule and anterior talofibular ligament were detached from their original sites. The calcaneofibular ligament was also detached with its associated periosteum and a tiny avulsed bony fragment. The articular facets of the tibia and talus were intact. The treatment consisted of wound irrigation, debridement, reduction and capsular suture followed by immobilization with a short leg cast. About 10 degrees of loss in the range of dorsiflexion was observed. The patient achieved good long-term functional results.