Traumatic Ulnar Dislocation of the Thumb Carpometacarpal Joint: A Case Report

Traumatic dislocation of the thumb carpometacarpal (CMC) joint is relatively rare. Although there are scattered reports of such dislocations, they are all in the dorsoradial direction. We report a very rare case of an ulnar dislocation of the CMC joint of the thumb. The patient fell while on a motorcycle and was presented with an ulnar dislocation of the CMC joint of the left thumb. Manual reduction failed to provide stability, and surgery was performed. The CMC joint was temporarily wired, and the posterior oblique ligament and dorsoradial ligament were repaired with a suture anchor. One year after surgery, the CMC joint was stable and pain-free.