Juvenile osteochondritis dissecans is an idiopathic condition involving subchondral bone and articular cartilage in skeletally immature patients in whom the growth plates are open, potentially leading to lesion instability. Because of the differing forces experienced by baseball/softball catchers versus position players, the age at which lesions develop and the characteristics of the lesions themselves may differ between these 2 populations. The purpose of the study was to examine relative age and characteristics of osteochondritis dissecans (OCD) knee lesions in catchers compared with position players.