Deltoid Ligament Rupture in Ankle Fracture: Diagnosis and Management

The last stage of a supination-external rotation ankle fracture involves either transverse fracture of the medial malleolus or rupture of the deltoid ligament. When the deltoid ligament ruptures, a "bimalleolar equivalent" ankle fracture occurs, and the surgeon is presented with several diagnostic and therapeutic challenges. In the native ankle, the deltoid ligament provides restraint to eversion and external rotation of the talus on the tibia. In bimalleolar equivalent ankle fractures, there is often gross medial instability even after fibular reduction. Retraction of the deltoid with subsequent healing in a nonanatomic position theoretically may cause instability, persistent medial gutter pain, and loss of function with risk of early arthritis. In mild cases, deltoid injury may not be obvious, and potential diagnostic techniques include preoperative and intraoperative stress radiography, MRI, and ultrasonography. The most common injury pattern is avulsion from the medial malleolus, and most current repair techniques involve direct repair of the capsular and deltoid injuries involving suture anchors in the medial malleolus and imbrication of the superficial and deep deltoid fibers. To date, there is limited evidence of superior clinical outcomes with the addition of deltoid repair compared with open reduction and internal fixation of the fibula alone.