How To Diagnose Lateral Ankle Injuries

By Remy Ardizzone, DPM, and Ronald L. Valmassy, DPM

Weighing The Etiology And Impact Of Chronic Lateral Ankle Instability

   Following an inversion ankle sprain and particularly following repeated inversion ankle sprains, there is a risk of developing chronic lateral ankle instability due to repeated stretching or tearing of the lateral collateral ankle ligaments.    The lateral collateral ankle ligaments consist of the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. Typically, an inversion ankle sprain results in injury to either the anterior talofibular ligament or calcaneofibular ligaments.9 Frequently, both of these ligaments will be injured to some degree.1 Given its location deep to the peroneal tendons in the posterior ankle, the posterior talofibular ligament rarely sustains significant injury.3 By contrast, the anterior talofibular ligament is the most frequently injured ligament in the lateral ankle. It is also the only one of these three ligaments that is intracapsular.6    Injuries to the lateral collateral ligaments are typically classified as grade 1, 2 or 3.10 Grade 1 injuries are characterized by stretching or inflammation of one or more of the ligaments. Grade 2 injuries, which are most common, consist of partial tearing of one or more of the ligaments. Grade 3 injuries involve complete rupture of one or more of the ligaments. Early reduction of swelling and prompt initiation of physical therapy are key to regaining full function and stability.1 Outcome studies of grade 3 injuries have shown little difference between conservative and surgical treatment in terms of stability, strength and one’s ability to return to full activities.11    Without physical therapy, the ligaments will heal in a “stretched out” or loosened position that contributes to instability. Employing U-shaped padding about the lateral malleolus in combination with compression promptly after the injury can minimize the swelling. It is the persistent swelling about the ligaments that helps maintain the stretched out position. Using an ankle stabilizer brace will help support the ligaments while allowing normal ankle function and alignment. Physical therapy not only helps patients regain full strength but also facilitates proprioception, which is essential in preventing instability.    While the ankle sprain is a common injury, chronic lateral ankle instability typically requires a history of recurrent inversion sprains. Patients will often complain that the affected ankle feels “unstable” or “gives out” frequently. They typically feel unsteady when walking on uneven ground or sloped surfaces. Repeat inversion injuries will occur with the slightest provocation. Not uncommonly, these patients report twisting or spraining their ankles every few months with varying levels of severity.7,12 Bracing or taping may not provide adequate stability.    Clinically, physical examination findings commonly reveal persistent swelling to the anterolateral aspect of the ankle, even if there has been no recent re-injury. There may or may not be tenderness to palpation of the anterior talofibular ligament or calcaneofibular ligament. Typically, one will see a positive anterior drawer sign or anterior displacement of the talus from the tibia, similar to what clinicians would see with an acute ankle injury. There is also increased inversion of the talus in the ankle mortise, particularly when one compares this to the contralateral ankle. When there is attempted rotary motion of the ankle within the mortise, the talus will often translocate laterally.

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