The Effect of Dual Mobility Articulations on Re-Revision After Revision for Dislocation.

Abstract

Recurrent instability remains a challenge after revision total hip arthroplasty (THA). This study evaluated whether dual mobility (DM) acetabular constructs used during revision for instability are associated with lower re-revision rates than fixed-bearing constructs. A retrospective analysis of the Michigan Arthroplasty Registry Collaborative Quality Initiative identified 796 patients who underwent revision of elective primary THA for dislocation; resurfacing, conversion, and urgent cases were excluded. Cumulative percent revision (CPR) curves were compared using log-rank testing. A Cox proportional hazards frailty model analyzed time to re-revision across DM, non-DM, and constrained liner groups, adjusting for revision year/era and site-level clustering. Multivariable logistic regression served as a sensitivity analysis for odds of re-revision within two years. The two- and five-year CPRs were 12.6% (95% CI [confidence interval], 10.1 to 15.0) and 17.1% (95% CI, 14.0 to 20.0), respectively. DM constructs had significantly lower CPR than non-DM (P = 0.022). At one year, CPR was 5.1% (95% CI, 2.1 to 8.0) versus 11.3% (95% CI, 7.7 to 14.8); at two years, 7.3% (95% CI, 3.6 to 10.8) versus 14.2% (95% CI, 10.2 to 18.0). By five years, confidence intervals overlapped (12.7 versus 20.2%). On adjusted analysis, non-DM constructs had significantly higher odds of re-revision within two years (OR 2.04; 95% CI, 1.2 to 3.5; P = 0.009). The DM constructs are associated with significantly lower early all-cause re-revision risk following revision THA for dislocation, with absolute risk reductions of 6.2% at one year and 6.9% at two years. Later estimates are less precise due to declining at-risk counts, and definitive conclusions regarding longer-term equivalence cannot be drawn. These findings support selective DM use in high-risk patients and highlight the need for long-term surveillance.