Revision reverse total shoulder arthroplasty in patients 65 years old and younger: outcome comparison with older patients

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) is a procedure growing in prevalence among younger populations. Consequently, its use in revision arthroplasty is growing in this demographic. However, studies examining the functional outcomes of revision RTSA in younger populations compared with older populations are lacking. The primary purpose of this study is to evaluate the functional outcomes of revision RTSA in patients 65 years old and younger compared with older patients who underwent revision RTSA. We hypothesized that younger patients would have similar outcomes to older patients and both groups would demonstrate improvement in outcomes. METHODS: A retrospective review was conducted on a prospectively collected research database at a single tertiary referral center of all patients who underwent RTSA between 2007 and 2018. Patients 65 years old or younger who underwent a revision RTSA and had minimum 2-year follow-up were evaluated. A control group of patients ≥70 years old who underwent revision RTSA were also evaluated. Demographics, surgical factors, active range of motion (ROM), and patient-reported outcomes (PROMs) were compared. The ROM parameters measured were forward elevation, abduction, external rotation, and level of internal rotation. The PROMs collected included American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, University of California–Los Angeles score, Constant score, normalized Constant, and Shoulder Pain and Disability Index 130. The differences in outcomes were compared against the minimal clinically important difference and substantial clinical benefit reported for primary reverse shoulder arthroplasty. RESULTS: A total of 81 patients undergoing revision RTSA were evaluated at a mean follow-up of 4.5 years with 42 patients in the study group and 39 patients in the control group. Both groups demonstrated similar demographics and rates of prior surgeries. Preoperative outcome scores were lower in the study group (≤65 years old) than those in the older control group with American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, and Shoulder Pain and Disability Index 130 remaining worse postoperatively. Both groups experienced statistically significant improvements in ROM from before operation to after operation, with slightly higher improvements in overhead motion in the younger cohort. Both the study group and the control group demonstrated statistically significant improvements in all PROMs with improvement above the substantial clinical benefit for the Constant and Simple Shoulder Test scores. Despite lower functional outcomes reported in the study group postoperatively, the improvement from before operation to after operation in all PROMs was similar between groups. CONCLUSION: Revision RTSA is a viable option for patients ≤65 years old with a poorly functioning shoulder arthroplasty. ROM and outcome improvements are similar compared with older patients undergoing revision RTSA, but the preoperative and postoperative functional outcomes are worse in the younger patients.