Posttraumatic ulnar translation of the carpus.

Ulnar translation of the carpus is a rare posttraumatic carpal instability pattern, in which the entire carpus is displaced ulnarward on the radioulnar surface. No previous formal reports of this problem have been located although it has been described in general discussions of wrist instability. Seven men and one woman were diagnosed with this condition although the diagnosis was delayed from 2 to 23 months, an average of 7.3 months. Three patients were treated surgically before diagnosis; the other five patients were treated conservatively before diagnosis. At the time of definitive diagnosis the radiographs showed an ulnar translation of the carpus, which was quantified on the radiographs in all eight patients by the method of Chamay. Four patients had an attempt to repair the radiolunate and radiocapitate ligaments. One patient had a ligamentous augmentation of the radiocapitate ligament complex. Two patients had ligamentous repairs of a scapholunate dissociation; one of these had simultaneous radiocarpal ligamentous augmentation. The eighth patient had a radiolunate arthrodesis. Follow-up averaged 32 months. Three patients had formal wrist arthrodeses at 10, 13, and 26 months after initial ligamentous repair, which were considered treatment failures. In the remaining five patients, four had partial recurrent ulnar shift, which was seen radiographically. Of these, three patients rated the result as good, with near normal strength and returned to full activities while two obtained fair results, with minimal pain but decreased range of motion and decreased strength. One patient has shown progressive degenerative radiocarpal changes and may become a candidate for a limited or formal wrist arthrodesis.