Idiopathic chondrolysis of the ankle.

A 21-year-old West Point cadet presented to our institution with a history of chronic left lateral ankle instability. The initial injury occurred 5 years earlier. Physical examination results and stress radiographs were consistent with lateral instability. The patient underwent an ankle arthroscopy and lateral ankle ligament reconstruction. Arthroscopic findings included moderate synovitis, grade II anterolateral chondrosis, and an anterior talar osteophyte. The patient had an uneventful postoperative course and returned to activity. Eleven months after surgery he presented with increased left ankle pain. On physical examination he had a stable ankle, but radiographs revealed marked loss of ankle joint space. Significant diffuse fraying and thinning of the articular cartilage noted on repeat arthroscopy were consistent with chondrolysis.