Does Approach Influence the Dislocation Rate Following Head and Liner Exchange in Revision Hip Arthroplasty

Abstract Introduction Modular component exchange can limit morbidity by retaining well-fixed hip arthroplasty components but dislocation has been a relatively frequent postoperative complication. This study evaluated the effect of surgical approach on dislocation rate in a modern revision cohort. Methods From 2010 to 2020, 248 aseptic head and liner exchanges were performed at a single institution including 54 done via the direct anterior (DA), 80 via the direct lateral (DL), and 114 via the posterolateral (PL) approach. The mean patient age at revision was 64.9±10.4 years and 50% (123/248) were performed among males. Indications for revision included 140 (56%) for polyethylene wear, 68 (27%) for failed metal-on-metal components, and 40 (16%) for instability. The mean follow-up after revision was 2.3 years. Results Thirty (12%) patients dislocated at a mean of 0.6 years (range, 0.01 to 4.6 years) postoperatively. The dislocation rate stratified by revision approach was 17% (9/54) for the DA, 6% (5/80) for the DL, and 14% (16/114) for the PL approach (p=0.13). Hips revised by the DA that dislocated were more abducted (51±8 vs. 45±8, p=0.05) and more anteverted (26±9 vs. 20±7, p=0.08) than non-dislocators. Among all 248 hips, cups with more than 48 degrees of abduction were 2.6 times more likely to dislocate (p=0.01). Head diameter, neck length, patient age, and sex were not associated with dislocation (p≥0.20). Discussion and Conclusion Dislocation remains a common complication after head and liner exchange regardless of approach. Cup position contributes to postoperative instability and must be critically evaluated during preoperative planning.