Internal Rotation Limitation is Prevalent Following Modern Reverse Shoulder Arthroplasty and Negatively Affects Patients' Subjective Rating of the Procedure.

BACKGROUND: While forward elevation, abduction, and external rotation are often successfully restored, internal rotation (IR) is frequently not satisfactorily recovered following reverse shoulder arthroplasty (RSA), affecting patients' ability to perform certain daily activities. This study examined the prevalence of limited IR in patients receiving modern RSA and its impact on clinical outcomes and patient satisfaction with their RSA.

METHODS: A cross-sectional study was conducted on patients who had undergone primary RSA using a modern RSA prosthesis with a minimum one-year follow-up. Patients returned for a research visit where they were examined for range of motion and surveyed for patient-reported outcome measures (PROMs) and subjective rating of the success level of their RSA. Postoperative range of motion data were compared with the preoperative data. The relationship of postoperative IR with PROMs and patients' subjective rating of RSA was analyzed. Logistic regression was performed to identify factors affecting patients' subjective rating of RSA.

RESULTS: A total of 78 patients met the criteria and completed the study. A significant portion (59%) reported subjective IR limitations, and 41% showed objective IR limitations. Comparison of preoperative and postoperative IR showed that 24% had worsened IR, while 33% improved. Limited IR was associated with lower patients' subjective rating of RSA and negatively impacted PROMs, especially when the dominant side was operated on. Regression analysis showed that limited IR was the only independent determining factor that was significantly associated with lower subjective rating of RSA.

DISCUSSION: Despite advancements in RSA design, limited IR remains a prevalent issue, significantly affecting patients' satisfaction and clinical outcomes. This study underscores the need for setting appropriate expectations regarding IR through patient education and focused efforts to improve IR limitations in RSA patients, particularly on the dominant side.