Review Question - QID 523

Osteochondritis dissecans (OCD) is an acquired, potentially reversible idiopathic lesion of subchondral bone resulting in delamination and sequestration with or without articular cartilage involvement and instability. While there is a typical location (medial femoral condyle) and thickness, these do not appear to be predictive of healing. A fluid signal on MRI behind the lesion indicates that the fragment is unstable and is less likely to heal according to DeSmet et al. The correct answer comes from a 12-patient study where Paletta et al reviewed quantitative bone scans to find that 100% of patients with open femoral physes that had activity behind the lesions went on to heal but none healed in adolescents with closing physes.