Knee, Osteochondritis Dissecans of the

Abstract

Osteochondritis dissecans (OCD) of the knee is a somewhat rare cause of knee dysfunction and pain that has been recognized for over one hundred years, but the etiology is still poorly understood. The ROCK (Research in Osteochondritis Dissecans of the Knee) Study Group recently summarized the currently recognized pathophysiology of osteochondritis dissecans as being an acquired subchondral lesion characterized by osseous resorption, collapse, and sequestrum formation. While the term osteochondritis dissecans was originally proposed by Konig in 1887 to suggest an inflammatory etiology for these mysterious osteochondral lesions, the exact etiology is still unknown. The highest incidence is in patients between the ages of 10 and 20 years, and males have a much higher incidence of osteochondritis dissecans than females. The most common location for osteochondritis dissecans lesions of the knee is the distal femur, specifically in the lateral aspect of the medial femoral condyle. Patients with osteochondritis dissecans can present with knee pain as the primary complaint, or osteochondritis dissecans can be discovered incidentally on radiographs obtained for unrelated injuries. Osteochondritis dissecans lesions are diagnosed with imaging, and most can be identified with plain radiographs. The most important prognostic factor involves the skeletal age of the patient at the time of symptom onset. More than half of pediatric osteochondritis dissecans cases treated conservatively will demonstrate healing within 6 to 18 months, while adults with osteochondritis dissecans of the knee frequently require surgery.