Medial Ankle Instability
Practitioners often focus on the lateral ankle ligaments because these are more commonly injured, but the medial ankle ligaments also play a role in ankle stabilization. In fact, medial ligaments are injured in up to 72% of patients with severe lateral ankle sprains.[6,7] The medial ankle ligaments have a complex structure with five main ligaments: tibiospring, tibiocalcaneal, posterior and anterior deep tibiotalar, and superficial posterior tibiotalar (Figure 2). Biomechanically, this deltoid ligament complex has an important role in both stabilizing the ankle and preventing the lateral displacement of the talus or tilt within the ankle mortise.
Medial ankle structures: deltoid ligaments demonstrated and bony landmarks. A, Superficial deltoid; (B) deep deltoid (1) origin of superficial posterior tibiotalar ligament, (2) posteromedial talar tubercle, (3) sustentaculum tali, (4) spring ligament, (5) tuberosity of navicular, (6) talar neck, (7) anterior malleolus, and (8) distal center of intercollicular groove.
Medial-sided ankle injuries are associated with pronation-eversion forces rather than the typical inversion associated with lateral-sided injuries. On examination, pain along the anteromedial ankle over the deltoid ligament is commonly encountered. In the chronic setting, hindfoot valgus may develop from attenuation of medial support structures. Surgical indications include talar subluxation and positive or persistent instability after lateral ligament stabilization.
Several options for medial ligament repair exist. Regardless of the surgical option chosen, the surgeon needs to be aware of the posterior tibial tendon just posterior to the medial malleolus. Suture anchor or transosseous sutures may be used, and no direct head-to-head comparisons of the two techniques currently exist in the literature. In patients with chronic medial instability, anatomic allograft reconstruction can be considered.
J Am Acad Orthop Surg. 2021;29(1):e5-e13. © 2021 American Academy of Orthopaedic Surgeons