Reverse total shoulder arthroplasty for patients with minimal preoperative pain: a matched-cohort analysis

Abstract

Profound improvements in function have been described in patients following reverse total shoulder arthroplasty (RSA). Previous studies have demonstrated young age, high preoperative function, and neurologic dysfunction to be predictors of poor functional improvement. However, no study to date has focused on patients electing to undergo RSA for function more than pain. The purpose of this study was to compare the outcomes of RSA in patients with minimal preoperative pain with those in patients who have higher baseline pain. We performed a retrospective matched-cohort study of RSA patients treated by a single surgeon with a minimum of 2 years' follow-up. Patients with at least moderate baseline pain (function-pain group), predefined by existing literature as a visual analog scale pain score > 3, were matched 3:1 based on sex, indication, and age to patients with minimal pain (function group), defined as a visual analog scale score ≤ 3. Patient-reported outcome measures, active range of motion, and overall satisfaction were compared. The percentage of maximal improvement in outcomes and the proportion of patients exceeding the established threshold that predicts excellent satisfaction were also compared. A total of 260 patients (195 in function-pain group and 65 in function group) were selected for matched analysis with a similar sex distribution; the mean age was 73.1 years, and the mean follow-up period was 50 months. No differences in most recent postoperative function, overall improvement in functional scores, and active motion were found between patients in the 2 groups (P > .05). However, pain scores improved only in patients with at least moderate baseline pain (P < .0001). Patient satisfaction was significantly different (P = .035), as 10.8% of patients who elected to undergo RSA for function were unsatisfied. The function cohort also had worse percentage of maximal Simple Shoulder Test score (P = .034) and American Shoulder and Elbow Surgeons score (P < .0001) improvement, and a lower proportion of these patients exceeded the threshold for the percentage of maximal improvement that predicts an "excellent" outcome (P < .0001). RSA patients with minimal preoperative pain achieve significant improvements in function and motion similar to those who choose to undergo RSA for both pain and function, but they are less satisfied and are less likely to achieve an excellentoutcome. Patients electing to proceed with RSA with minimal pain should be counseled accordingly.