When do patients truly reach maximal medical improvement after undergoing reverse shoulder arthroplasty? The incidence and clinical significance of pain and patient-reported outcome measure improvement

HYPOTHESIS: Patients receiving reverse total shoulder arthroplasty (RTSA) may reach MMI prior to 12 months postoperatively. BACKGROUND: With the growth of RTSA indications, there is a paucity of information regarding maximum medical improvement (MMI) after these procedures. Systems of evaluating recovery, such as patient-reported outcome measures and minimal clinically important differences (MCIDs) will allow for measurement of when patients reach maximum medical improvement (MMI) after these procedures. PURPOSE: To evaluate when patients have reached MMI after RTSA. METHODS: Patients were prospectively enrolled in the institution's RTSA registry. All patients undergoing RTSA who agreed to be enrolled were included. Patient-specific factors, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, and pain data were collected preoperatively and at 6 and 12 months postoperatively. Subgroup analysis was performed on preoperative diagnosis before analyzing MCID and MMI. MMI was calculated by using the last time point interval that an MCID did not occur. RESULTS: Of 182 patients, 92 had complete 12-month postoperative data, including visual analog scale (VAS) pain and ASES scores. Subgroup analysis showed preoperative diagnosis of rotator cuff arthropathy, revision surgery, glenohumeral arthritis, proximal humerus fracture, and chronic dislocation. All 5 groups had improvement that exceeded MCID thresholds at 6 months and variable improvement from 6-12 months. Analysis of variance compared the different groups, showing that VAS pain scores and ASES scores were different at all time points except for preoperative VAS pain scores. CONCLUSIONS: Patients undergoing RTSA may reach MMI at 6 months instead of the previously reported 1-year time point. Data from this study can allow providers to deliver value care and potentially limit visits after 6 months postoperatively.