The purpose of this study was to review the long-term outcomes of a previously reported prospective series of 46 type III acromioclavicular dislocations. These were treated surgically with temporary fixation of the acromioclavicular joint with wires, repair of the acromioclavicular ligaments, and overlapped suture of the deltoid and trapezius muscles. Of the 46 patients, one had died, four could not be traced, and three declined to return for follow-up, leaving 38 patients in the study. There were 36 men and two women, with a mean age at follow-up of 57.3 years (41 to 71). The mean follow-up was 24.2 years (21 to 26). Patients were evaluated using the Imatani and University of California, Los Angeles (UCLA) scoring systems. Their subjective status was assessed using the Disabilities of the Arm, Shoulder and Hand and Simple Shoulder Test questionnaires, and a visual analogue scale for patient satisfaction. The examination included radiographs of the shoulder. At a follow-up of 21 years, the results were satisfactory in 35 (92.1%) patients and unsatisfactory in three (7.9%). In total, 35 patients (92.1%) reported no pain, one slight pain, and two moderate pain. All except two patients had a full range of shoulder movement compared with the opposite side. Unsatisfactory results were the result of early redisplacement in two patients, and osteoarthritis without redisplacement in one. According to the Imatani and UCLA scores, there was no difference between the operated shoulder and the opposite shoulder (p >
0.05). Given the same situation, 35 (92.1%) patients would opt for the same surgical treatment again. Operative treatment of type III acromioclavicular joint injuries produces satisfactory long-term results.