We report a retrospective study of eighteen patients with pain in the knee or ankle, eleven of whom had osteochondritis dissecans. In these patients the bone-flow time-activity curves were observed after an intravenous injection of a bolus of 99mTc MDP. The curves varied according to the severity of the clinical signs and symptoms. The diagnosis rate was 29% with static scintigraphy and this improved to 57% when dynamic flow studies were used. A positive pattern in the dynamic study together with radiographs and static scintigraphs raised the diagnosis rate to 100%; the sensitivity was 90%. These preliminary results show that dynamic bone scintigraphy holds promise as a technique for identification and management of this condition.