The results of resection of the medial end of the clavicle to treat a painful sternoclavicular joint in fifteen patients were retrospectively reviewed. The patients fell into two groups: eight patients who had had a primary arthroplasty of the sternoclavicular joint in which the costoclavicular ligament was left intact (group I), and seven patients who had had revision of a failed arthroplasty of the sternoclavicular joint and in whom the costoclavicular ligament had to be reconstructed (group II). The results for these two groups were compared at an average of 7.7 years postoperatively. All eight patients in group I had an excellent result. In sharp contrast, three patients in group II had an excellent result, three had a fair result, and one had a poor result. We conclude that preservation or reconstruction of the costoclavicular ligament is essential at the time of resection of the medial portion of the clavicle in order to obtain a satisfactory result.