Comparing Inferiorized and Lateralized Glenospheres in Reverse Total Shoulder Arthroplasty Using the LimaCorporate SMR Reverse Shoulder System: A Single-Center Analysis.

BACKGROUND: Limited evidence compares reoperation, patient-reported outcomes (PROs), and mortality between inferiorized and lateralized glenospheres in reverse total shoulder arthroplasty (rTSA).

METHODS: Single-institution retrospective review was performed of all primary rTSAs performed by a single surgeon using the LimaCorporate SMR Reverse Shoulder System between 2014 and 2025. Demographics, surgical data, reoperation, mortality, and PROs were obtained; American Shoulder and Elbow Surgeons (ASES) and visual analog scale (VAS) pain scores were collected preoperatively and postoperatively between 6 and 12 months. Cumulative incidence of reoperation (CIR) was estimated using competing-risks methodology with death as a competing event; group differences were assessed using Fine-Gray regression. Inverse probability weighting (IPW) was used to adjust for confounding in multivariable regression analyses assessing the association between glenosphere type and each endpoint.

RESULTS: Overall, 329 inferiorized and 131 lateralized glenospheres were included with respective mean ages of 72.9 and 71.6 years (p=0.60), minimum follow up of 12 months, median follow-up of 31.3 and 12.2 months (p<0.001), and PRO completion percentages of 59% and 64% (p=0.77). There were no significant differences between inferiorized and lateralized glenospheres with respect to 36-month CIR (4.9% versus 4.4%; p=0.37), with similar findings at 12 and 24 months, improvements in ASES (46.2 vs. 50.2; p=0.26) or VAS pain (-4.2 vs. -4.2; p=0.97), minimal clinically important difference achievement for ASES (87.1% vs. 84.5%; p=0.57) or VAS pain (82.5% vs. 78.6%; p=0.50), and mortality (4% vs. 1.5%; p=0.25). Glenosphere type was not significantly associated with CIR, reoperation, PROs, or mortality.

CONCLUSION: Within the limitations of this retrospective study, inferiorized and lateralized glenospheres using the LimaCorporate SMR Reverse Shoulder System demonstrated comparable short-term clinical outcomes despite differing follow-up durations between cohorts. Longer-term follow-up is needed to determine whether clinically meaningful differences emerge over time.

LEVEL OF EVIDENCE: Level III, Retrospective Cohort Comparison, Treatment Study.