Radioulnar synostosis following an isolated fracture of the ulnar shaft. A case report.

In the case of a 19-year-old man, overuse of his nondominant forearm resulted in a radioulnar synostosis. Despite the persistence of the synostosis, the patient adapted to loss of forearm rotation. No further treatment was necessary. Isolated fractures of the ulnar shaft are slow in healing. Several authors observed that early function may be beneficial. However, excessive activity causing motion at the fracture site may cause subperiosteal hemorrhage and soft tissue trauma and may stimulate exuberant callus formation. Fractures of the ulnar shaft, even undisplaced, need to be immobilized to prevent overuse.