A Comparison Of Revision Rates For Dislocation And Aseptic Causes Between Dual Mobility And Large Femoral Head Bearings In Primary Total Hip Arthroplasty With Subanalysis By Acetabular Component Size An analysis of 106,163 primary total hip replacements

Abstract Background Dual-mobility (DM) and large femoral head bearings (≥36mm) both decrease the risk of dislocation in total hip arthroplasty (THA). There is limited comparable data in primary THA. This study compared the revision rates for dislocation and aseptic causes between DM and large femoral heads and subanalyzed by acetabular component size. Methods Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) were analyzed for patients undergoing primary THA for osteoarthritis from January 2008 (the year of first recorded DM use) to December 2019. All DM and large femoral head bearings were identified. The primary outcome measure was the cumulative percent revision (CPR) for dislocation and for all aseptic causes. Results were adjusted by age, sex, and femoral fixation. A sub-analysis was performed stratifying acetabular component diameter Results There were 4,942 DM and 101,221 large femoral head bearings recorded. There was no difference in the CPR for dislocation (HR = 0.69 (95% CI 0.42, 1.13), p=0.138) or aseptic causes (HR = 0.91 (95% CI 0.70, 1.18), p=0.457). When stratified by acetabular component size, DM reduced the CPR for dislocation in acetabular component diameter Conclusions There is no difference in revision rates for dislocation or aseptic causes between DM and large femoral heads in primary THA. When stratified by acetabular component size, DM reduces dislocation for acetabular component diameter Level of Evidence Level III