What are the Rates of Recurrent Dislocation and Re-Revision after Revision Total Hip Arthroplasty for Instability?

Abstract

Instability is a leading cause of revision total hip arthroplasty (rTHA). This study aimed to (1) determine rates of recurrent dislocation and re-revision following rTHA for instability and (2) identified patient- and surgical risk factors associated with failure. Patients who underwent revision THA at our institution between 2016 and 2024 for a primary indication of instability were included. A total of 242 patients who met inclusion criteria, including 10 (4.1%) using a direct anterior approach, whereas the remaining 232 were performed using a postero-lateral approach (95.9%). Outcomes of interest included recurrent dislocation and re-revision for instability. Multivariable logistic regression was performed to identify independent predictors of failure. There were 36 patients (14.9%) who experienced at least one dislocation after rTHA and 27 patients (11.2%) who required re-revision after a mean of 1.3 dislocations, at a median of 126 days from revision surgery. On adjusted multivariable analyses, prior spinal fusion was independently associated with an increased risk of redislocation (OR [odds ratio] 3.51, 95% CI [confidence interval] 1.40 to 8.58; P < 0.01), while use of a preoperative hip-spine workflow was associated with reduced risk of redislocation (OR 0.43, 95% CI 0.18 to 0.97; P < 0.05) and re-revision (OR 0.38, 95% CI 0.13 to 0.96; P < 0.05). Smaller femoral head size (≤32 mm) increased the risk of re-revision (OR 5.20, 95% CI 1.26-16.19; P = 0.04), whereas technology-assisted surgery and dual-mobility articulations were not associated with improved outcomes. In this large cohort, rTHA performed for instability was associated with substantial rates of recurrent dislocation and re-revision at a mean follow-up of 4.1 years. These findings emphasize the multifactorial nature of instability post-revision and support the integration of patient-specific spino-pelvic assessment into surgical decision-making to optimize stability after rTHA.