Comparison between Anatomic Total Shoulder Arthroplasty and Reverse Shoulder Arthroplasty for Older Adults with Osteoarthritis without Rotator Cuff Tears.

Background: Many older adults with glenohumeral osteoarthritis without rotator cuff tears experience muscle atrophy and fatty degeneration. In these cases, range of motion (ROM) recovery and clinical results after total shoulder arthroplasty (TSA) could be poor, with low subjective satisfaction after surgery. The purpose of this study was to compare the clinical outcomes of anatomic TSA and reverse shoulder arthroplasty (RSA) in patients aged over 70 years with primary glenohumeral osteoarthritis without rotator cuff tears. We hypothesized that the clinical outcomes of anatomical TSA would be better than those of RSA.

Methods: This single-center, retrospective comparative study involved patients who underwent TSA or RSA from 2013 to 2020. Clinical outcomes were assessed using the American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, and active ROM preoperatively and at the follow-up. Walch classification and glenoid version angle were measured using preoperative computed tomography, and fatty infiltration of supraspinatus and infraspinatus muscles were checked through preoperative magnetic resonance imaging.

Results: Of the 67 patients included in this study, TSA was performed in 41 patients (TSA group), and RSA was performed in 26 patients (RSA group). The two groups had no clinical differences in the patients' preoperative demographic and radiographic data. At the final follow-up, both groups showed improved pain, ROM, and functional outcomes. Moreover, the TSA group demonstrated significantly better postoperative ASES (86.8 ± 6.3 vs. 81.6 ± 5.5, p = 0.001) and Constant-Murley (80.4 ± 5.7 vs. 73.4 ± 6.2, p < 0.001) scores than the RSA group. The TSA group showed a significantly better postoperative active ROM than the RSA group regarding forward flexion as well as external and internal rotations (p < 0.001). All patients in the RSA and TSA groups exceeded the minimal clinically important difference.

Conclusions: In older adult patients with degenerative glenohumeral osteoarthritis wherein the rotator cuff is preserved without excessive bone loss, anatomic TSA and RSA can improve pain, ROM, and clinical outcomes. However, clinical results and ROM were better with TSA than with RSA during the short- and mid-term follow-up periods.