The Knee: Osteochondritis Dissecans

Abstract

Osteochondritis dissecans (OCD) of the knee is a focal stress reaction to the subchondral bone that often occurs in skeletally immature adolescent athletes. It classically occurs at the posterolateral aspect of the medial femoral condyle, and the majority can be diagnosed with plain radiographs if four views are performed including a intercondylar notch view. It presents with activity-related knee pain. MRI is useful for determining lesion stability. Stable OCD lesions are treated conservatively with activity modification and/or limitation of weight bearing. Operative intervention is reserved for stable lesions that do not heal after 6–9 months of conservative management, for large stable lesions in children approaching skeletal maturity and for most unstable lesions especially if symptomatic. Arthroscopic drilling is the commonly accepted treatment for stable lesions while internal fixation is added for unstable lesions. Unsalvageable OCD lesions devoid of subchondral bone are generally treated initially with debridement and excision, followed by a cartilage repair technique microfracture, osteochondral autograft transplantation, or autologous chondrocyte implantation. Excellent short-term results have been reported with these techniques; though, long-term data are lacking regarding the future development of osteoarthritis in this young patient population.