All-Polyethylene Tibial Components Are Associated With an Increased Rate of Failure Compared to Metal-Backed Unicompartmental Knee Arthroplasty: A Meta-Analysis of 34,647 Reconstructed Individualised Patient Data Publisher



M Poursalehian MOHAMMAD ; S Hajiaghajani SINA ; As Farsani Ali SOLTANI ; Cj Hecht Christian J ; Af Kamath Atul F
Source: Knee Surgery, Sports Traumatology, Arthroscopy Published:2025

Abstract

Purpose: The comparative survivorship of all-polyethylene (AP) versus metal-backed (MB) tibial components in unicompartmental knee arthroplasty (UKA) remains unclear, as previous studies mainly used relative risk without comprehensive time-to-event analysis. Methods: Following PRISMA guidelines, a systematic review and meta-analysis were performed. Databases (PubMed, Scopus, Embase and Web of Science) were searched without restrictions. Included studies compared MB and AP tibial components in UKA. Risk of bias was assessed using ROBINS-I and RoB-2 tools. Hazard ratios (HRs) were derived from reconstructed Kaplan–Meier data. Analyses used both IPD reconstruction (Log-rank test) and meta-analysis methods. Results: After screening 2577 records, 18 studies comprising 35,639 knees (21,610 MB; 14,029 AP) were included. Eleven studies found no difference in survivorship, six favoured MB and one favoured AP. However, pooled IPD analysis of 34,647 knees showed a survival advantage for MB (HR for AP vs. MB = 1.55, 95% confidence interval [CI]: 1.45–1.65, p < 0.0001). Revision rates at 2, 5 and 10 years were lower for MB (3.0%, 5.9% and 11.1%) compared to AP (4.4%, 9.2% and 17.2%). Aseptic loosening was the most common cause of failure, typically occurring after 5 years of implantation. The meta-analysis of reconstructed HRs indicated moderate-to-high heterogeneity (I² = 60%), with a pooled HR of 1.70 (95% CI: 1.28–2.27, p < 0.001). No publication bias was detected, and sensitivity analyses confirmed the robustness of the results. Conclusions: MB tibial components in fixed-bearing UKA show a lower risk of revision compared to AP components. Despite limited data on exact failure times and variations in implant design, the findings suggest that AP components in fixed-bearing UKA are less favourable. Level of Evidence: Level III. © 2025 Elsevier B.V., All rights reserved.