Magnetic resonance imaging findings of chronic lateral ankle instability.

The ankle inversion injury is one of the most common types of injury that is encountered in athletes and active individuals. There are a wide variety of acute injuries associated with ankle inversion, including peroneal tendon tears, osteochondritis dessicans of the talus, anterior talofibular ligament avulsion, peroneal retinaculum avulsion, and calcaneofibular ligament tears. Chronic sequelae include impingement, posttraumatic degenerative arthritis, and an attenuated peroneal retinaculum. Most inversion injuries to the ankle have multiple associated injuries and isolated ligament injuries are uncommon. Chronically, the injured ankle usually demonstrates the injuries found at the time of the initial injury. Subsequently, there is a high frequency of these injuries in patients evaluated for symptoms of chronic lateral ankle instability. A high index of suspicion for the specific types of injuries associated with ankle inversions may result in a higher rate of injury detection and more expeditious and accurate diagnoses. Given the persistence of these injuries seen in patients with chronic posterolateral instability, injury patterns of ankle inversion are important to recognize even in the absence of acute trauma. We review the various types of injuries with their associated magnetic resonance (MR) imaging characteristics seen in patients with chronic lateral ankle instability.