An isolated ring finger metacarpal shaft fracture?--beware an associated little finger carpometacarpal joint dislocation.

Dislocations of the ulnar carpometacarpal joint are easily missed because of a low index of suspicion as well as their subtle clinical and radiological features. Often, the presence of a more obvious adjacent injury also draws attention away from the carpometacarpal joint. Two cases of ring finger metacarpal shaft fractures with associated little finger carpometacarpal joint dislocations are presented. In both cases, the metacarpal fractures were diagnosed but the carpometacarpal joint dislocations were initially overlooked. The presence of an apparently isolated ring finger metacarpal fracture due to an indirect force should raise the possibility of an associated carpometacarpal joint injury.