All-polyethylene, hybrid, and modern metal-backed glenoid components show relevant but not significantly different outcomes in anatomic total shoulder arthroplasty: A systematic review.

Abstract

Anatomic total shoulder arthroplasty (aTSA) is one of the most common orthopedic procedures performed in the United States, with all-polyethylene (PE) glenoid components long being recognized as the gold standard for total shoulder arthroplasty (TSA) implant design. However, the emergence of modern metal-backed glenoid (MBG) and hybrid glenoid implant designs offers alternatives to the traditional construct. The purpose of this systematic review is to investigate the difference in clinical and radiographic outcomes between the three glenoid component designs. Following PRISMA guidelines, this systematic review grouped included studies as all-polyethylene (n = 19), hybrid (n = 5), and MBG (n = 13). Primary outcomes assessed radiolucency, complication rates, revision rates, range of motion (ROM), and patient-reported outcomes (PROMs). Between-group comparisons were performed across the three cohorts. No significant difference was found between the MBG, all-polyethylene, and hybrid glenoid implant groups in radiolucency (P = 0.30) and revision rates (P = 0.28). Additionally, between the three implant designs, no significant difference was observed in any PROMs or ROM measurements. Meta-regression revealed longer follow-up times were associated with increased reported revision, complication, and radiolucency rates (P < 0.001 for all). In anatomic TSA, hybrid, cemented all-polyethylene, and modern metal-backed implant designs did not demonstrate statistically significant differences in radiolucency, complications, revisions, PROMs, or ROM. However, meta-regression results suggest follow-up duration may be associated with higher reported revision, complication, and radiolucency rates. Because the hybrid and modern metal-backed literature is relatively novel and follow-up is less standardized, these comparative findings should be considered preliminary. Non-significant but higher complication and revision estimates in the PE group merit continued monitoring. Given the increasing utilization of aTSA, additional long-term comparative studies with defined standardized outcomes and implant-stratified reporting are necessary to provide a more definitive analysis of glenoid implant performance.