Reverse total shoulder arthroplasty for primary osteoarthritis with restricted preoperative forward elevation demonstrates similar outcomes but faster range of motion recovery compared to anatomic total shoulder arthroplasty

Background Reverse total shoulder arthroplasty (RSA) has been increasingly utilized for a variety of shoulder pathologies that are difficult to treat with anatomical shoulder arthroplasty (TSA). Few studies have compared the outcomes of TSA versus RSA in patients with cuff intact GHOA and poor preoperative forward elevation. This study aimed to determine whether there is a difference in functional outcomes and postoperative ROM between TSA and RSA in these patients. Methods This retrospective cohort study included 116 patients who underwent RSA or TSA between 2013 and 2022 for the treatment of rotator cuff intact primary osteoarthritis with restricted preoperative forward flexion (FF) and a minimum 1-year follow-up. Each arthroplasty group was divided into two subgroups: patients with preoperative FF between 91 and 120 degrees or FF lower than or equal to 90 degrees. Patients' clinical outcomes, including active range of motion (ROM), American Shoulder and Elbow Surgeons (ASES) score, Visual analog scale (VAS) for pain, and Subjective Shoulder Value (SSV) were collected. Clinical and radiographic complications were evaluated. Results There was no significant difference between RSA and TSA in terms of sex (58.3% male vs 62.2% male, p=0.692), or follow-up duration (20.1 months vs 17.7 months, p=0.230). However, the RSA cohort was significantly older (72.0± 8.2 vs 65.4 ± 10.6, p=0.012) and weaker in FF and ER before surgery (p<0.001). There was no difference between RSA (57 patients) and TSA (59 patients) in VAS pain score (1.2 ± 2.3 vs 1.3 ± 2.3, p=0.925), SSV score (90 ± 15 vs 90 ± 15, p=0.859) or ASES score (78.4 ± 20.5 vs 82.1 ± 23.2, p=0.476). Postoperative active ROM was statistically similar between RSA and TSA cohorts in FF (145 ± 26 vs 146 ± 23, p= 0.728), and ER (39 ± 15 vs 41 ± 15, p= 0.584). However, IR was lower in the RSA cohort (p <0.001). This was also true in each subgroup. RSA led to faster postoperative FF and ER achievement at 3 months (p<0.001). There was no statistically significant difference in complication rates between cohorts. Conclusion This study demonstrates that patients with GHOA who have a structurally intact rotator cuff but limited preoperative forward elevation can achieve predictable clinical improvement in pain, range of motion, and function after either TSA or RSA. Reverse arthroplasty may be a reliable treatment option in patients at risk for developing rotator cuff failure.