Clinical results of conservative versus operative treatment of acromial and scapular spine fractures following reverse total shoulder arthroplasty

BACKGROUND Acromial and scapular spine fractures are common complications after reverse total shoulder arthroplasty (RTSA). There is limited information on the treatment outcome of these fractures. Therefore, the purpose of this study was to compare the clinical outcome of operative and conservative treatment of patients with acromial or scapular spine fractures. METHODS A total of 1146 RTSAs were performed in our institution between 1999 and 2016. In 23 patients (2%), we identified an acromial fracture, and in 7 cases (0.6%), a scapular spine fracture in the postoperative course. Of those patients, 7 patients (23%) were treated with open reduction and internal fixation and 23 (77%) were treated conservatively. We compared the outcome of operative vs. conservative treatment assessing the Constant score (CS), range of motion, and subjective shoulder value (SSV). Fractures were classified by the system of Crosby. Radiographic assessment consisted of measuring the healing rate, time to heal, and the displacement of the acromion before and immediately after the fracture as well as after treatment. RESULTS There were no statistically significant differences between operative and conservative treatment. The mean preoperative CS in the operative group was 32 points and improved to 45 points after surgery, whereas it was 35 points in the conservative group and improved to 61 points at the final follow-up. The mean SSV improved from 20 to 50 points in the operative group and from 22 to 58 points in the conservative group. Mean active flexion changed from 59° to 75°, mean abduction from 68° to 67°, and external rotation from 25° to 13° in the operative group and from 75° to 91°, 67° to 92°, and 28° to 24° in the conservative group. CONCLUSIONS In our study, operative treatment was not superior to conservative treatment, neither for CS, SSV, or range of motion. Both treatment forms, however, resulted in inferior results to those previously reported for RTSA without postoperative acromion fractures. Before better surgical methods have been developed, conservative treatment of acromial fractures may be the better treatment option for acromial fractures after RTSA