Osteochondritis dissecans of the talus: case report on two family members.

Historically the investigators studying the etiology of osteochondritis dissecans can be grouped into two schools: (a) those considering trauma to previously normal bone as the chief cause; and (b) those noting causes other than trauma as being the primary reason for the lesion's development. In the case studies presented here, three medial lesions in two siblings are discussed. In neither case could trauma be substantiated.