Meta-Analysis of Brand-Mixed Versus Brand-Unmixed Primary Total Hip Arthroplasty

Background/Objectives: Mixing implant components from different manufacturers in primary total hip arthroplasty (THA) remains controversial because of concerns regarding implant compatibility and revision risk. This systematic review and meta-analysis aimed to compare revision outcomes between brand-mixed and brand-unmixed primary THA. Methods: A PRISMA-compliant systematic review of PubMed/MEDLINE and Embase identified studies comparing brand-mixed and brand-unmixed primary THA. Reported time-to-event estimates were pooled as hazard ratios (HRs), and revision-event counts as odds ratios (ORs), using random-effects models. Results: Six retrospective observational studies comprising 1,185,948 primary THAs were included. The time-to-event analysis did not identify a statistically significant difference in all-cause revision between brand-mixed and brand-unmixed THA (HR 1.03; 95% CI 0.97-1.08; I² = 0%). The complementary crude revision-event analysis likewise did not identify a statistically significant difference (OR 1.01; 95% CI 0.83-1.24), although substantial heterogeneity was present (I² = 93%). A post hoc exploratory sensitivity analysis excluding metal-on-metal and ceramic-on-metal bearings and brand-mixed stem-head constructs was based on two studies and yielded an OR of 0.97 (95% CI 0.79-1.20; I² = 95%). Certainty of evidence was low for the time-to-event analysis and very low for the event-based analyses. Conclusions: Available observational evidence did not identify a statistically significant association between brand mixing and all-cause revision following primary THA. However, these findings do not establish equivalence, universal component compatibility, or the safety of specific brand-mixed combinations and should be interpreted in light of the observational study designs, residual confounding, and heterogeneity in implant constructs.