Irreducible fracture dislocation of the ankle caused by tibialis posterior tendon interposition.

A patient with severe irreducible open fracture dislocation of the ankle was admitted to our emergency department. After wound irrigation and debridement, skeletal traction was applied to the calcaneus to minimize soft tissue injury and swelling. The patient was followed in traction for 1 week, after which reduction and fixation of the fibula was attempted but not achieved. We extended the incision distally, visualized the ankle, and located the tibialis posterior tendon between the distal tibia and fibula, thereby inhibiting the reduction. The tendon coursed into the tibiotalar joint anteriorly and pushed the talus anterolaterally. After manipulation of the tendon to its anatomically correct location, the ankle was easily reduced. The wound at the medial side was closed with a fasciocutaneous rotational flap. The ankle was then immobilized for 6 weeks postoperatively. The patient regained her full range of motion, and there were no problems with the tibialis posterior tendon, such as rupture or insufficiency. Isolated tibialis posterior tendon interposition between the distal tibiofibular and tibiotalar joints has rarely been reported, and can inhibit anatomical reduction of the fractured ankle.