Acute Tibialis Posterior Tendon Rupture With Pronation-Type Ankle Fractures.

Tibialis posterior tendon rupture in the setting of pronation-type ankle fractures can lead to long-term debility as a result of chronic tendon dysfunction. This rare injury pattern presents a diagnostic challenge because thorough preoperative examination of the function of the tendon is limited by pain, swelling, and inherent instability of the fracture. As such, a high index of suspicion is necessary in ankle fractures with radiographs showing a medial malleolus fracture with an associated suprasyndesmotic fibula fracture. This report describes 3 cases of tibialis posterior tendon rupture associated with pronation-type ankle fractures treated acutely with open reduction and internal fixation and primary tendon repair. Additionally, common features of this injury pattern are discussed based on the current literature. In accordance with this report, the typical mechanism of injury is high energy and includes forced pronation, external rotation, and dorsiflexion of the ankle, which places maximal stress on the tibialis posterior tendon. Rupture most commonly occurs in a relatively hypovascular area of the tendon located at the posteromedial extent of the medial malleolus fracture. In the operative treatment of pronation-type ankle fractures, direct inspection of the tibialis posterior tendon allows for timely diagnosis and treatment of associated ruptures. [Orthopedics.2016; 39(5):e970-e975.].