Single center evaluation of outcomes of modular dual mobility liners during revision total hip arthroplasty: A five-year follow-up

Introduction: Revision total hip arthroplasty (rTHA) is at increased risk for postoperative instability when compared to primary cases, which has been mitigated to some extent with the introduction of dual mobility (DM) reconstructions. These constructs were designed to lower dislocation rates and to improve impingement-free range of motion. As a follow-up to our prior institutional study, we expanded on a cohort of DM reconstructions compared to non-DM constructs. We examined a modular dual mobility system in rTHA to measure loosening of the acetabular component, as well as revision and dislocation rates in comparison to an historical cohort of single articulation prostheses. Materials/Methods: This retrospective cohort study from a single center included 254 patients who underwent rTHA with a dual mobility liner by three fellowship-trained surgeons between January 1, 2014 and December 1, 2019. This was a follow-up to an historical cohort of revisions performed with a single articulation prosthesis (n = 120) from the same surgeons performed between January 1, 2011 and December 23, 2013. The inclusion criteria included consecutively performed rTHAs that had a minimum follow-up of 2 years. We excluded patients who had femoral revisions and head/liner revisions only. The average follow-up in the dual mobility cohort and the single articulation cohort was 5 years (range, 2-10 years) and 2.5 years (range, 1.5-4.3 years), respectively. The primary outcomes were dislocation, aseptic loosening, and re-revision rates. Secondary outcomes were radiographic analyses of cup migration and osteolysis. Results: There were 4 out of 256 (1.6%) dislocations from the dual mobility cohort compared to 7 out of 120 (5.8%), P < 0.001 from the single articulation cohort. The rates of aseptic loosening were 3.2% (8 out of 254) and 4.2% (5 out of 120), P = 0.124, respectively, between the cohorts. The re-revision rate was 5.9% for the DM liners and 8.3% in the control cohort, P = 0.38. Radiographic analyses revealed no cup migration and osteolysis in any of the patients that had no dislocations. Conclusion: The dual mobility articulations in rTHA demonstrated improved results in terms of lower dislocations rates when compared to a single articulation prostheses. Our center uses these articulations for revisions and surgeons should consider the use of these bearings when performing rTHA.