Fibular nonunion and equinovarus deformity secondary to posterior tibial tendon incarceration in the syndesmosis: a case report after a bimalleolar fracture-dislocation.

A 39-year-old woman sustained a grade II open bimalleolar fracture-dislocation of the left ankle. Six months after an ORIF of these fractures was performed, she presented with a nonunion of the distal fibula fracture and with a fixed hindfoot equinovarus and forefoot adduction deformity. At surgery for repair of the fibular nonunion, the posterior tibial tendon (PTT) was found to be entrapped in the posterior tibiotalar joint, with a portion of the tendon interposed between the tibia and the fibula in the area of the posterior syndesmosis. After extrication of the PTT, the hindfoot varus and forefoot adduction deformity were corrected. To our knowledge, this is the first case report in the English literature of a missed PTT syndesmotic entrapment that resulted in a fibular nonunion and in a fixed foot deformity after an open bimalleolar ankle fracture dislocation.