Anatomic and Reverse Total Shoulder Arthroplasty for Dislocation Arthropathy Yield Comparable Functional Outcomes to Matched Cohort

Abstract Background The aim of this study was to compare outcomes of anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA) following prior shoulder stabilization versus matched cohorts without previous stabilization surgery. Hypotheses were: (1) patients undergoing aTSA or rTSA after stabilization procedures would have worse outcomes compared to matched cohorts, and (2) patients undergoing total shoulder arthroplasty would have better outcomes following soft-tissue stabilization procedures (aTSAST/rTSAST) compared to bony stabilization procedures (aTSAB/rTSAB). Methods Retrospective cohort study was performed comparing (1) 36 aTSA and (2) 32 rTSA patients with prior shoulder stabilization with 3-to-1 matched cohorts (based on age, gender, follow-up length) with no prior shoulder instability or surgery. Baseline demographics, peri-operative data, adverse events (AE), radiographic outcomes, functional outcome scores, range of motion (ROM), and patient satisfaction were analyzed. Subgroup analyses compared aTSAST/rTSAST patients with aTSAB/rTSAB patients. Results Postoperative AE rate was 8.3% and 4.6% in the aTSA group and matched cohort, respectively (p=0.404), with a trend towards a significantly higher incidence of aseptic glenoid loosening in the aTSA group (8.3% vs. 1.9%, p=0.067). Functional outcomes, ROM, and patient satisfaction did not differ at follow-up >4-years. In the subgroup analysis, two AE required reoperation among 25 aTSAST patients versus one among 11 aTSAB patients; all related to aseptic loosening. There was a trend towards greater functional outcomes and satisfaction among aTSAST patients. There was a trend towards a clinically significant difference in active abduction at final follow-up favoring aTSAST (128 vs. 108 degrees, p=0.096). Postoperative AE rate was 6.3% and 4.2% among the rTSA group and matched cohort, respectively (p=0.632). Functional outcomes, ROM, and patient satisfaction did not differ at 4-year follow-up . In the subgroup analysis, no AE were reported among 18 rTSAST and 14 rTSAB patients. A trend towards greater functional outcomes and patient satisfaction favored rTSAB patients, who achieved greater improvements in ROM from baseline, and greater ROM in all planes at final follow-up. Conclusion Both aTSA and rTSA are reliable options for the treatment of dislocation arthropathy in appropriately selected patients. aTSA and rTSA after prior shoulder stabilization procedures have nearly equal rates of AE, and yield similar clinical and functional outcomes as matched cohorts. There may be an increased risk of glenoid aseptic loosening in aTSA after prior shoulder stabilization. Functional outcomes tend to be greater for aTSAST compared to aTSAB patients. On the contrary, rTSA may optimize postoperative function when performed for dislocation arthropathy following bony rather than soft-tissue stabilization procedures.