Comparing optimum prosthesis combinations of total stemmed, stemless and reverse shoulder arthroplasty revision rates for men and women with glenohumeral osteoarthritis.

Background: This study investigated prostheses from a large national arthroplasty registry with the lowest rates of revision, defined as optimum. We compared optimum shoulder arthroplasty revision rates for osteoarthritis (OA) to determine the most suitable/effective procedure for men and women.

Methods: There were three cohort groups of optimum primary shoulder arthroplasties for OA undertaken between 1st January 2008 and 31 December 2022: stemless shoulder arthroplasty with cemented polyethylene glenoids (slTSA), stemmed shoulder arthroplasty with modified central peg polyethylene glenoids (stTSA), and cementless reverse shoulder arthroplasty (rTSA). The cumulative percent revision (CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazard models adjusted for age, gender, humeral head/glenosphere size, polyethylene type, and surgeon volume. Possible interactions were examined. A sub-analysis from 1 January 2017 captured additional patient demographics, ASA score, BMI and glenoid morphology.

Results: The CPR at 7 years was 4.0%(95% confidence interval (CI) 3.1, 5.1) for slTSA (n=3,041), 3.8%(95%CI 2.7, 5.5) for stTSA (n=1,259) and 4.1%(95%CI 3.7, 4.6) for rTSA (n=12,341). slTSA had a higher rate of revision compared to rTSA after the first 9 months (p<0.001). rTSA had a lower revision rate compared to stTSA from 3 months on (p=0.004). After adjusting for other confounders, prosthesis type and gender were associated with revision rates (p<0.001) whereas surgeon volume was not. Additionally, gender and prosthesis type strongly interacted (p=0.013) and the combined model exhibited greater predictive performance when including this interaction. Women had lower rates of revision than men for both stTSA and rTSA, but not slTSA. Most revisions were for infection in men, especially rTSA. After 3 months, the rate of revision for slTSA vs rTSA for women was increased (p<0.001) and revision rates for men did not significantly differ. However, in a sub-analysis of procedures in males since 2017 with additional adjustments, slTSA had a lower revision rate than stTSA (p=0.010).

Conclusions: The optimum shoulder arthroplasty revision rates vary for both the gender and implant type for the diagnosis of OA. A model combining optimum prostheses and gender predicted revision better than optimum implants alone. After 3 months, rTSA was associated with lower revision rates compared to slTSA in women, whereas there were no significant differences between optimum prostheses in men. However, surgeons may also consider lower revision risk of optimum slTSA at sub analysis and increased cumulative incidence of infection for rTSA requiring revision to resolve decision making for male patients.