In this series are presented thirteen cases of osteochondritis dissecans of the talus, one of which showed bilateral symmetrical involvement of the ankle (Table I). Twelve of the patients were males and one was a female; all were white. The occupation of the individual apparently had no relation to the onset or causation of the condition.

Trauma is a major etiological factor, although in this series four patients gave no history of ankle injurry. Seven of the patients had had either severe sprains or recurrent sprains of the involved ankle; two patients had had direct trauma. The duration of symptoms ranged from two months to four years, the average being 21.4 months. Since there was involvement of the right ankle in eight cases and of the left ankle in six cases, there would seem to be no more likelihood of the lesion appearing on one side of the body than on the other. Of the fourteen ankles involved, three lesions were located on the superolateral aspect of the talus; in eleven cases the site of involvement was on the superomedial articular surface of the talus. In one case there was bilateral involvement, with the lesions located on the superomedial aspect of each talus, adjacent to the medial malleolus. In six of the cases, operation was performed. That surgical intervention was not employed in more cases was due to several factors. Some patients did not desire operation and, since most of these cases occurrred among military personnel, surgical intervention was not employed, because of existing Army regulations which prohibited operation in longstanding cases.