Dual-mobility implants in primary and revision total hip arthroplasty: A systematic review and meta-analysis

Abstract

Purpose: Total hip arthroplasty (THA) is a common and successful operation. However, dislocation remains a significant cause of implant failure in fixed-bearing designs. This study investigated the effect of dual-mobility implants (DM) compared to fixed-bearing (FB) implants on all-cause revisions, revisions due to dislocation, post-operative complications and functional scores in patients undergoing primary and revision THA.

Methods: A systematic review was performed including studies that compared DM with FB implants in primary or revision THA according to PRISMA guidelines, and was registered in PROSPERO (ID CRD42023403736). The Cochrane Library, Embase, MEDLINE, Web of Science, and Scopus were searched from the time of database inception to March 12, 2023. Eligible studies underwent meta-analysis and risk of bias assessment using the ROBINS-I tool. Treatment effects were assessed using odds ratios and data were pooled using a random-effects maximum-likelihood, where appropriate.

Results: Eight comparative, non-randomised studies involving 2810 DM implants and 3188 FB implants were included. In primary THA, there was an imprecise estimate of the difference in all-cause revision (OR 0.82, 95 % CI 0.25-2.72) and a significant benefit for the DM cohort in revision due to dislocation (OR 0.08, 95 % CI 0.02-0.28). In revision THA, the DM cohort showed benefit in all-cause revision (OR 0.57, 95 % CI 0.31-1.05) and revision due to dislocation (OR 0.14, 95 % CI 0.04-0.53). DM implants were associated with a lower incidence of implant dislocation and infection. The analysis of functional outcomes was limited due to reporting limitations. No intraprosthetic dislocations were observed.

Conclusion: The results suggest that contemporary DM designs may be advantageous in reducing the risk of all-cause revision, revision due to dislocation, and post-operative complication incidence at mid-term follow-up. Further high-quality prospective studies are needed to evaluate the long-term risk profile of this design, especially in the revision context.

Keywords: Dislocation; Dual-mobility implants; Implant failure; Meta-analysis; Post-operative complications; Revision surgery; Systematic review; Total hip arthroplasty; Total joint replacement.

Fig. 1

(A) Exploded view of a Zimmer Biomet G7 dual mobility acetabular system (B) Assembled view of a Zimmer Biomet G7 dual mobility acetabular system. The small ceramic head, large liner, outer metal cup, and acetabular shell are arranged from top to bottom and inside to outside in (A) and (B), respectively. The primary articulation occurs between the small ceramic head and the large polyethylene liner (Images courtesy of Zimmer Biomet, Warsaw).

Fig. 2

A PRISMA flow diagram, providing a visual representation of the systematic review process, including the study identification, screening, and inclusion phases, and the consequent number of included studies in the systematic review and meta-analysis. n: number.

Fig. 3

(A) A traffic light plot of the domain-level risk-of-bias judgement for each included study. The colours indicate the deemed risk of bias, with green indicating low risk, yellow indicating moderate risk and red indicating serious risk. The overall risk of bias corresponds to the worst judgement obtained across all of a study's domains. (B) Unweighted bar plots illustrating the distribution of the risk of bias judgements within each domain. The risk-of-bias assessment involved careful examination of each study and comparison against an idealised study design to evaluate the risk of bias in each domain. This required in-depth methodological and content expertise to identify potential biases and assess their impact on the overall results. The idealised study design was a hypothetical benchmark that allowed the assessment of each included study in a consistent and rigorous fashion.

Fig. 4

Contour-enhanced funnel plots, shown as the distribution precision (Standard Error, y-axis) against the effect size estimate (Odds Ratio, x-axis). Milestones of statistical significance indicated at p = 0.01, 0.05 and 0.10 (A) (Upper Left) All-cause revision in the pTHA studies. (B) (Upper Right) All-cause revision in the rTHA studies. (C) (Lower Left) Revision due to dislocation in the pTHA studies. (D) (Lower Right) Revision due to dislocation in the rTHA studies.

Fig. 5

Forest plots. Shown as the individual studies (y-axis) against the effect size estimate (Odds Ratio, x-axis). The effect size estimate is portrayed by a point estimate and 95 % CIs (horizontal line) that reflect the precision of the estimate. The null effect line is portrayed as a black vertical line intersecting one. The overall weighted effect size is given as a dashed vertical red line and diamond. DL: DerSimonian-Laird. (A) All-cause revision in the pTHA studies. (B) All-cause revision in the rTHA studies. (C) Revision due to dislocation in the pTHA studies. (D) Revision due to dislocation in the rTHA studies.