Revision reverse total shoulder arthroplasty: clinical and radiographic outcomes compared to primary reverse total shoulder arthroplasty

Reverse total shoulder arthroplasty (rTSA) has surpassed anatomic total shoulder arthroplasty in popularity due to its superior outcomes in patients with rotator cuff deficiency and other complex shoulder pathologies. While primary rTSA demonstrates excellent functional improvements, revision rTSA remains challenging, with limited data available on outcomes. Previous studies on revision total shoulder arthroplasty have primarily focused on anatomic total shoulder arthroplasty, with fewer studies evaluating revision rTSA outcomes. The purpose of this study is to compare the clinical and radiographic outcomes of a primary rTSA to a revision rTSA. A prospective multicenter shoulder registry of a single manufacturer's implants (Equinoxe, Exactech, Inc., Gainesville, FL, USA) was used to conduct a retrospective review of patients who underwent revision of an rTSA to another rTSA and compare them to those who received a primary rTSA for osteoarthritis and rotator cuff disease between 2007 and 2023 with a minimum follow-up of 2 years. Cohorts were matched 3:1 (control: revision) by age, gender, body mass index, and length of follow-up. Those who underwent revision for humeral fracture, infection, or an unknown reason were excluded. Preoperative and postoperative range of motion and patient-reported outcome measures were compared. Other outcomes included scapular notching, complications, revisions, and patient satisfaction. There were 52 rTSA revised to an rTSA compared to 156 matched primary rTSA. The mean age was 69 years, 40% were female, and the mean follow-up was of 56 months. The revision group had significantly less postoperative abduction (108&#xb0; vs. 128&#xb0;, adjusted P = .023), forward elevation (120&#xb0; vs. 145&#xb0;, adjusted P = .003), and external rotation (28&#xb0; vs. 38&#xb0;, adjusted P = .023) compared to the control group, with all exceeding the minimal clinically important difference. All patient-reported outcome measures in the revision cohort were significantly worse than those in the primary rTSA cohort and exceeded the minimal clinically important difference. Patient satisfaction rate in the revision cohort was significantly lower than the primary cohort (80% vs. 92%, adjusted P = .011). Complication (31% vs. 6%, adjusted P < .001) and revision (12% vs. 3%, adjusted P = .050) rates were significantly higher in the revision cohort, while humeral radiolucent line and scapular notching rates were similar between the 2 groups. Although patients undergoing revision rTSA demonstrated worse functional outcomes, including decreased range of motion, increased pain, and lower patient satisfaction compared to those undergoing primary rTSA, both groups significantly improved from their preoperative conditions. Additionally, complication and revision rates were higher in the revision cohort. These findings highlight the challenges associated with revision rTSA.