Primary Treatment of Complex Proximal Humerus Fractures Using Humelock Cementless Reversible Shoulder Arthroplasty in the Elderly

Background Proximal humerus fractures are quite common, constituting 5% of all fractures. Plate osteosynthesis of comminuted fractures in the elderly with osteoporotic bones is prone to complications, including loss of reduction, intraarticular protrusion of screws, avascular necrosis and non-union. Hemiarthroplasty may be preferred to achieve a stable fixation, which permits early shoulder motion. Prerequisites for the successful functional outcome of this surgical technique are to have an intact rotator cuff, which is often torn, and achieve proper soft tissue balance, which is technically demanding. In RSA design, deltoid muscle replaces the function of the supraspinatus, compensating for a dysfunctional rotator cuff or a displaced tuberculum. We designed a retrospective study to evaluate the results of proximal humerus fractures treated with reverse shoulder arthroplasty using Humelock II reversible prosthesis in elderly patients. Methods Thirty-one patients (25 females, six males) above 65 years old who underwent reverse shoulder arthroplasty between 2014 and 2019 for Neer 3-4 part fractures or head split injuries were included in this study. Patients with a previous internal fixation attempt, cases with neurological deficit or previous upper extremity fractures, patients who presented later than three weeks after the trauma, cases with less than six months follow-up and patients with additional fractures were excluded. Twenty-eight patients were available for final analysis. Fracture mechanism, time from trauma till surgery, hospital stay and preoperative ASA scores were noted. Humelock II Reversible (FX Solutions) implants were used in all cases. Patients' shoulder range of motion and functional outcome using UCLA, DASH and Constant scores at minimum six months follow-up were evaluated. Results The mean age was 72.2 (65-95) years, and mean follow-up time was 15.5 (6-48) months. The mean UCLA, Constant and Dash scores at the last follow-up were 27.6 (14-35), 67.9 (38-80) and 30.8 (9.9-79.2), respectively. Mean shoulder flexion, abduction, internal and external rotation were 130 (110-160), 100 (70-140), 40 (15-60) and 39 (15-75) degrees, respectively. Conclusion RSA is a very reliable treatment for proximal humerus fractures in patients over 65 years old. Early active and passive shoulder exercises can be started postoperatively, and good functional outcome and wide ROM can be achieved with this age group. Although stable fixation of the tuberculum is not required for shoulder abduction, it facilitates external rotation and should be attempted in all cases. Clinical outcomes of patients who underwent RSA due to proximal humerus fracture are as good as the outcomes of patients with different etiologies.