Trabecular metal versus non-trabecular metal acetabular components and the risk of re-revision following revision total hip arthroplasty: A propensity score-matched study from the National Joint Registry for England and Wales

Background: Studies have suggested that Trabecular Metal (TM)-coated acetabular components may reduce implant failure following revision total hip arthroplasty. However, these studies have predominantly been limited to small, single-center cohorts, with many lacking a comparator group. Using National Joint Registry data from England and Wales, we compared re-revision rates following revision total hip arthroplasty between TM and non-TM-coated acetabular components from 1 manufacturer. Methods: This retrospective observational study included all revision total hip arthroplasties performed with use of 1 of 4 cementless acetabular components produced by the same manufacturer (Zimmer Biomet). The acetabular components either had a TM surface coating (TM Modular and Continuum designs) or a non-TM surface coating (Trilogy and Trilogy IT designs). Revision total hip arthroplasties with TM and non-TM implants were matched for multiple potential patient and surgical confounding factors using propensity scores. Outcomes following revision total hip arthroplasty (re-revision for all acetabular indications, aseptic acetabular loosening, or infection) were compared between matched groups using competing risk regression analysis. Analyses were repeated in a subgroup initially revised for infection. Results: Of 3,862 matched revision total hip arthroplasties (1,931 in the TM group and 1,931 in the non-TM group), the overall prevalence of acetabular re-revision (2.7%; 95% confidence interval [CI] = 2.1% to 3.2%), re-revision for aseptic acetabular loosening (0.96%; 95% CI = 0.68% to 1.3%), and re-revision for infection (1.4%; 95% CI = 1.0% to 1.8%) were low. Six-year rates of re-revision for all causes (subhazard ratio [SHR] = 0.91; 95% CI = 0.61 to 1.35; p = 0.636), aseptic acetabular loosening (SHR = 1.32; 95% CI = 0.68 to 2.53; p = 0.410), and infection (SHR = 0.68; 95% CI = 0.39 to 1.20; p = 0.165) were similar between revision total hip arthroplasties with TM and non-TM coatings. Of 247 total hip arthroplasties initially revised for infection (116 TM and 131 non-TM), the rates of re-revision for all causes (SHR = 0.48; 95% CI = 0.15 to 1.56; p = 0.225), aseptic acetabular loosening (SHR = 0.54; 95% CI = 0.05 to 5.74; p = 0.608), and infection (SHR = 0.82; 95% CI = 0.28 to 2.36; p = 0.706) were similar between the TM and non-TM groups. Conclusions: Following revision total hip arthroplasty, TM-coated acetabular components had a low risk of both aseptic and septic re-revision, with rates that were comparable with those of non-TM components. Extended follow-up of large revision total hip arthroplasty cohorts will establish whether TM components have any clinical benefit over non-TM designs when used in patients with similar acetabular bone stock. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.