Side-to-side differences in postoperative function and patient satisfaction after bilateral total shoulder arthroplasties.

Abstract

As the number of anatomic and reverse total shoulder arthroplasty (TSA) procedures increase, there will be a natural increase in patients who undergo staged bilateral TSA procedures. Bilateral TSAs have been shown to improve patient outcomes; however, it is unknown whether these patients experience side-to-side differences in clinical outcomes and satisfaction between shoulders. Understanding these differences is imperative for accurate patient and provider expectations. An international multicenter registry was used to identify patients who underwent staged bilateral TSAs from April 2007 to October 2019 with a minimum of 2-year follow-up. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) outcomes and satisfaction ratings were compared between dominant and nondominant shoulders, and first and second arthroplasties. Side-to-side differences in postoperative ASES and unequal satisfaction ratings were also explored by using regression analyses to identify potential factors influencing these differences. A total of 60 patients (22 bilateral anatomic TSAs, 38 bilateral reverse TSAs) were identified for inclusion. Group analyses revealed that bilateral TSA patients demonstrated similar functional outcomes and satisfaction regardless of dominance and surgery sequence. Type of TSA, specifically bilateral reverse TSAs, significantly predicted greater side-to-side differences in postoperative ASES scores (P=.025), indicating reverse TSA patients demonstrated greater between-sides differences in postoperative functional outcomes compared with those undergoing anatomic TSAs. Additionally, a larger proportion of bilateral reverse TSA patients reported unequal satisfaction between shoulders (31.6%) compared with anatomic TSA patients (9.1%). Logistic regression analysis revealed that greater side-to-side differences in postoperative ASES scores were found to increase the likelihood of reporting unequal satisfaction between shoulders (odds ratio 1.11, P<.001), which may explain this outcome. Most patients who undergo bilateral TSAs can expect similar outcomes on both shoulders regardless of dominance and surgery sequence. However, we did find patients who had discordant results between shoulders. Those who underwent reverse TSAs more frequently reported unequal satisfaction with their TSA procedures, which is likely due to larger side-to-side differences in postoperative function. It is unclear why these differences occurred, but this information may be important for providers to remember when counseling these patients for accurate postoperative expectations.