Irreducible ankle fracture dislocation: a case report of posterior tibial tendon entrapment

Ankle fracture-dislocations are complex injuries that often involve displaced bones and significant soft tissue damage. In rare instances, the posterior tibial tendon can become incarcerated in the tibiofibular space, complicating standard reduction techniques. We present the case of a 61-year-old man who, eight weeks after a traffic accident, exhibited a Gustillo-Anderson IIIA open fracture-dislocation of the right ankle. Initial treatment involved wound debridement, external fixation, and fibular osteosynthesis. However, postoperative radiographs revealed persistent anterolateral displacement of the talus and widening of the medial clear space, necessitating further investigation. During definitive tibial fixation, the posterior tibial tendon, which had initially been missed, was found to be trapped between the tibia and fibula. Using an anteromedial approach, the tendon was successfully repositioned behind the medial malleolus. The patient experienced an uneventful recovery, achieving full ankle function and strength by 12 weeks, with stable fracture healing confirmed on radiographs. This case underscores the critical importance of early recognition of posterior tibial tendon entrapment in ankle fracture-dislocations, as delayed diagnosis can result in severe long-term complications.