Delayed diagnosis of posterior tibialis tendon interposition in the distal tibiofibular and tibiotalar joints after open fracture-dislocation of the ankle joint: A case report with a 10-year follow-up.

Irreducible ankle fracture-dislocations due to posterior tibialis tendon (PTT) interposition in the distal tibiofibular and tibiotalar joints are rarely reported, and their diagnoses are often missed and delayed. In addition, previous reports lacked a longer clinical follow-up period, and objective and subjective evaluations of such cases have not been reported. A 22-year-old man sustained an open fracture-dislocation of the ankle joint associated with a distal third of the fibular shaft fracture and diastasis of the distal tibiofibular joint. After open reduction and fixation of the fibula and distal tibiofibular syndesmosis, malreduced distal tibiofibular syndesmosis and anterior subluxation of the talus persisted. Magnetic resonance imaging (MRI) revealed PTT interposition in the distal tibiofibular and tibiotalar joints. Open reduction of the PTT was performed, resulting in reduction of the distal tibiofibular syndesmosis and talus. At the 10-year follow-up, the patient showed a normal gait but complained of ankle pain. The clinical outcome using subjective evaluation showed a low score on a subscale related to sports activity compared to the other subscales. It is difficult to diagnose PTT interposition in the distal tibiofibular and tibiotalar joints. However, based on the type of fracture and direction and degree of talar dislocation, a diagnosis can be made using computed tomography without MRI. It is important to evaluate clinical outcomes using both objective and subjective assessments because some disorders cannot be fully evaluated using conventional objective assessments.