Surgical treatment of the unstable ankle.

Symptomatic ankle instability will develop in as many as 20% of patients after inversion sprain of the lateral ankle ligaments. Although most patients may be successfully treated with a rehabilitative exercise program and bracing, some will continue to sustain recurrent ankle sprains with activities of daily living, work on uneven terrain, or sports. The anterior talofibular ligament and the calcaneofibular ligament are the primary stabilizers of the lateral ankle, and surgical procedures should be aimed at restoring the normal function of these ligaments. Preoperative stress radiographs should be obtained to determine the degree of laxity and to differentiate between subtalar joint and ankle joint instability. Numerous surgical techniques have been described to correct ankle instability, most with an 80% to 90% success rate. Reconstructions using tendon grafts may restrict normal ankle and subtalar joint motion, depending on the placement of the graft. Direct repair of the anterior talofibular and calcaneofibular ligaments with shortening and reattachment to the fibula has a success rate similar to that for augmented reconstruction and avoids the increased morbidity associated with tendon graft procedures. Patients with severe laxity or with weak or deficient tissue for direct repair may require an augmented reconstruction. Osteotomy may be required in addition to ligament reconstruction in patients with severe ankle or hindfoot varus alignment, in order to prevent failure of the repair. Patients with paralysis or weakness of the peroneal musculature may require a nonanatomic procedure that limits subtalar motion.