Unilateral posterior dislocation of the radial head in identical twins.

Congenital dislocation of the radial head, particularly bilateral, is seen in association with many syndromes affecting the musculoskeletal system. The consensus in the literature suggests that all isolated unilateral dislocations are posttraumatic in origin. Recent reports, therefore, recommend that unilateral dislocation be treated by open reduction, despite the benign natural history of the anomaly. We report on identical twins with isolated unilateral posterior dislocation in whom there is little doubt about the presence of the dislocation at birth.