Reverse Shoulder Arthroplasty for the Treatment of Malunion of Proximal Humeral Fractures

Introduction: Malunion is a common complication of displaced proximal humerus fractures. Although reverse shoulder arthroplasty (RSA) has been shown to be a compatible treatment option for various indications, its use in treating proximal humeral malunion raises a unique challenge. The distorted anatomy due to bony deformity and soft tissue changes complicates the surgery, leading several authors to question the validity of the procedure. The purpose of this study was to evaluate the clinical and radiographic results of patients with proximal humeral malunion that were treated with a reverse shoulder arthroplasty in our institute.

Methods: A retrospective review was conducted of patients who underwent RTSA in our institute between 2012 and 2016 with a minimum of 2 years of follow-up. Our search results yielded, 19 patients. The average follow up was 44 month (range 25-70). Indications for arthroplasty were severe shoulder pain and functional impairment, joint incongruity or secondary degenerative joint disease, in addition to failure of non-operative treatment.

Results: The average Constant score improved from 14.7 (4-27) to 55.3 (35-77). Age/sex adjusted CS improved from 19.5 to 77.9. The overall mean patient satisfaction score improved from 1/10 to 8.1/10 and the mean pain score improved from 2/15 to 11/15. We also found an overall improvement in active forward flexion from 43° to 115°, abduction from 40.5° to 100°, external rotation from 0° to 30° and internal rotation from 10° to 61°. The radiographic analysis showed no lucencies around the implants or subsidence. There were four cases of glenoid notching (grade 1-2) and five inferior glenoid spurs. Three cases had an intraoperative crack of the glenoid during riming that was treated with autograft bone augmentation.

Conclusion: The use of a stemless humeral component of RSA in cases of proximal humeral malunion indicates promising results, such as improved range of motion, decreased pain, and high rates of patient satisfaction.