Understanding How The Lateral Ankle Triad Comes Into Play With Chronic Ankle Instability

Babak Baravarian, DPM, and Lindsay Mae Chandler, DPM

One of the most commonly encountered musculoskeletal injuries and possibly the most common injury in sports is the lateral ankle sprain. Current estimates suggest that one out of 10,000 people per day sustains an inversion ankle sprain with lateral ankle sprains accounting for 85 percent of all ankle sprains.1-3

   Researchers have reported that approximately 20 to 40 percent of acute ankle sprains progress to chronic problems.4,5 Braun found that at six to 18 months after injury, 72.6 percent of patients reported residual pain after initially being treated in a general clinic.6 A study out of Hong Kong found that 59 percent of athletes with ankle sprains had significant disability and residual symptoms, which led to impairment of their athletic performance.7

   Numerous studies on sports injuries have revealed a high occurrence and high recurrence rate of ankle sprain. Chronic pain, muscular weaknesses and ease of giving way of the ankle are not uncommon for athletes with a history of ankle sprains who subsequently develop chronic ankle problems and chronic ankle instability.

A Closer Look At The Pathoanatomy Of The Lateral Ankle

The anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament comprise the lateral ankle ligament complex. The anterior talofibular ligament is the most frequently injured ligament in inversion sprains followed by the calcaneofibular ligament and rarely the posterior talofibular ligament. Brostrom and Linstrand reported that approximately two-thirds of ankle sprains are isolated to the anterior talofibular ligament.8,9 The anterior talofibular ligament runs parallel to the foot in a neutral position, is contiguous with the ankle joint and is the weakest of the lateral ankle ligaments. The calcaneofibular ligament is an extra-articular ligament, which crosses both the subtalar joint as well as the ankle joint, and acts as the floor of the peroneal sheath.

   Lateral ankle sprains are often not isolated findings and are frequently associated with other injuries such as peroneal tenosynovitis, anterolateral impingement lesions, ankle synovitis, intra-articular loose bodies, osteochondral lesions of the talus and tibia, adhesions, fibrous bands, and neuritis. Researchers have found that chronically unstable ankle joints can lead to degenerative changes as well as peroneal tendon pathology. Dombek and colleagues revealed that 58 percent of peroneal tears in their study resulted from trauma and 61 percent of those were secondary to ankle sprains.10

   Continued microtrauma and repetitive over-stretching of the capsule may take place with chronic ankle instability. Accordingly, this could lead to synovitis, synovial impingement and scarring of the capsule. Hintermann and coworkers evaluated chronic ankle instability via arthroscopy and found osteochondral defects of the talus or tibia in 55 percent of the cases, synovitis in 32 percent of the cases, synovial plica in 10 percent of patients, and ventral scarring in 5 percent of patients.5

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