Osteochondritis Dissecans of the Distal Femur and Patella

Osteochondritis dissecans (OCD) is a pathologic process of obscure cause characterized by a partial or total separation of a fragment of bone with overlying articular cartilage. The fragment is an avascular segment that separates, distinguishing it from an acute osteochondral fracture. OCD may affect any joint, but the knee joint is affected most commonly.57 The lesion may be bilateral, although it is usually unilateral.13, 24, 31, 57 It is the most common cause of loose bodies in the knee joint in young people.15