Osteochondritis dissecans of the capitellum in fraternal twins: case report.

The etiology of osteochondritis dissecans (OCD) of the capitellum is unknown but has generally been attributed to repetitive microtrauma or ischemia. We present a case report of fraternal twins with OCD lesions in their nondominant arms without a known history of repetitive injury to the elbow. This report provides evidence to support the idea of genetic predisposition for OCD lesions.