Treatment strategies for recurrent dislocation following total hip arthroplasty: relationship between cause of dislocation and type of revision surgery.

ABSTRACT

BACKGROUND: There are many therapeutic options for dislocation following total hip arthroplasty (THA). The aim of this study was to evaluate the results of revision surgery for dislocated hips. METHODS: Between November 2001 and December 2020, 71 consecutive revision hip surgeries were performed at our institution for recurrent dislocation following THA. We conducted a retrospective study of all 65 patients (71 hips), who were followed for a mean of 4.7 ± 3.2 years (range, 1-14). The cohort included 48 women and 17 men, with a mean age of 71 ± 12.3 years (range, 34-92). The mean number of previous surgeries was 1.6 ± 1.1 (range, 1-5). From intraoperative findings, we created six categories of revision hip surgery for recurrent dislocation following THA open reduction and internal fixation (2 hips); head change or liner change only (6 hips); cup change with increased head size only (14 hips); stem change only (7 hips); cup and stem change (24 hips); and conversion to constrained cup (18 hips). Prosthesis survival was analyzed by the Kaplan-Meier method, with repeat revision surgery for re-dislocation or implant failure as the endpoint. A cox proportional hazards model was used for risk factors of re-revision surgery. RESULTS: Re-dislocation occurred in 5 hips (7.0%) and implant failure in 1 hip (1.4%). The 10-year survival rate was 81.1% (95% confidence interval, 65.5-96.8). A Dorr classification of "positional" was a risk factor for re-revision surgery due to re-dislocation. CONCLUSION: Clear understanding of the cause of dislocation is essential for optimizing revision procedures and improving the rate of successful outcomes.