Atypical etiology of lateral collateral ligament disruption and instability.

This report describes 2 cases of a posteroinferior capitellum impaction osteochondral injury with associated avulsion of the supinator crest resulting from a fall onto an extended upper extremity. The injury pattern in both cases was detected on x-ray films, although fully appreciated on computed tomographic imaging. Posterolateral rotatory instability occurred in both patients. One patient underwent early operative intervention (4 days postinjury) and returned to normal within 5 weeks. Surgery was delayed for the second patient (13 weeks), who initially experienced unfavorable outcomes, although stability was ultimately restored operatively. To our knowledge, this injury pattern has not previously been described as the focus of a report.