Survivorship, Outcomes, and Risk Factors for Conversion to Total Hip Arthroplasty After Revision Hip Arthroscopic Surgery in Obese Patients: Results at a Minimum 5-Year Follow-up

BACKGROUND: There is a paucity of literature reporting outcomes after revision hip arthroscopic surgery in obese patients. PURPOSE: To report the minimum 5-year survivorship, patient-reported outcomes (PROs), clinical benefit, and risk factors for conversion to total hip arthroplasty (THA) in obese patients after revision hip arthroscopic surgery. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Data were prospectively collected and retrospectively reviewed for patients who underwent revision hip arthroscopic surgery by a single surgeon between April 2010 and August 2016. Inclusion criteria were a body mass index ≥30 and baseline and minimum 5-year postoperative values for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score–Sport-Specific Subscale (HOS-SSS), and visual analog scale (VAS) for pain. Exclusion criteria were Tönnis grade >1 and hip dysplasia. Survivorship was defined as no conversion to THA. Clinical benefit was measured using the minimal clinically important difference (MCID). Survivors and nonsurvivors underwent further bivariate and regression analyses to determine the predictors of conversion to THA. RESULTS: Included were 24 hips in 24 patients. The mean patient age was 39.3 ± 12.7 years, and the mean follow-up was 83.9 ± 26.5 months. The survivorship rate was 75.0%, and patients demonstrated a significant improvement in all PROs (P < .01). At 5-year follow-up, the MCID for the mHHS, NAHS, HOS-SSS, and VAS was achieved by 70.6%, 94.1%, 92.9%, and 64.7%, respectively, of the patients. Older age, higher grade ligamentum teres tears, and acetabuloplasty were significant on bivariate analysis for conversion to THA, and increased age was identified as a significant variable for conversion to THA on regression analysis (odds ratio, 1.297 [95% CI, 1.045-1.609]; P = .018), with a 29.7% greater risk for every additional year of age at the time of revision. CONCLUSION: In this study, 25.0% of obese patients who underwent revision hip arthroscopic surgery required conversion to THA. The study patients who did not need conversion to THA had a significant improvement in all PROs, with >90% achieving MCID for one or more outcome measures. Older age was identified as a significant predictor of conversion to THA.