MR imaging of the most commonly injured ankle ligaments. Part II. Ligament injuries.

Thirteen patients with clinically diagnosed sprained ankles underwent magnetic resonance (MR) imaging. Five of these cases are presented to illustrate the potential of MR imaging to enable identification of both primary and associated ligament injury sites, grading of the severity of the injuries, and visualization of the associated findings of tendon sheath and joint effusion. The appropriate combination of foot position and imaging plane is essential to achieve full-length visualization of each ligament. Two patients demonstrated findings compatible with total gross disruption of the anterior fibulotalar ligament; two, with injury to the fibulocalcaneal ligament with effusion of the overlying peroneus tendon sheath; and one, with thinning, lengthening, and fibrotic changes involving the anterior fibulotalar ligament. MR imaging can provide a noninvasive means to evaluate the site and severity of ankle ligament injuries (a) in acute ankle injuries that demonstrate significant instability, (b) in stable acute injuries involving athletes or litigation, or (c) in patients with repeated injuries or instability in whom surgery is contemplated.