In situ rotational dislocation of the trapezoid associated with carpal-metacarpal dislocations.

A rare case of in situ rotational dislocation of the trapezoid was described after dislocation of the index and long carpal-metacarpal joints. Due to the difficulty in visualising the trapezoid on plain radiographs, there was a delay in assessing the full extent of the injury. However, after further imaging, the case required open reduction and internal fixation. Therefore, in cases involving high energy dislocations of the second and third metacarpal CMC joints, injury to the peri-trapezoid ligaments should be considered. A pre-operative CT scan or, if not available, open fixation of the CMC joints and trapezoid, is recommended.