Predictors of Clinical Outcomes After Hip Arthroscopy: 5 Year Follow- Up Analysis of 1038 Patients

OBJECTIVES: Identify predictive factors of midterm outcomes after hip arthroscopy in a cohort of 1038 patients, whose outcomes at minimum 2-year follow-up have previously been reported. In addition, to provide a comparison of short-term and midterm predictive factors in outcome measures following hip arthroscopy. METHODS: Data were prospectively collected and retrospectively reviewed on all patients undergoing hip arthroscopy between February 2008 and June 2012. Patients were included if they had minimum 5-year follow-up on 3 patient reported outcomes: Nonarthritic Hip Score (NAHS), modified Harris Hip Score (mHHS), and Hip Outcome Score-Sport Specific Subscale (HOS-SSS). Patients were excluded if they had any prior ipsilateral hip conditions. Using bivariate and multivariate analyses, we analyzed the effect of 36 preoperative and intraoperative variables on NAHS. RESULTS: A total of 1038 patients met our listed inclusion and exclusion criteria, with a mean follow-up time of 62.0 months (range, 60.0 - 120.0 months). The bivariate analysis identified 11 variables (4 categorical and 7 continuous) that were predictive of 5-year postoperative NAHS. For the multivariate analysis, 7 variables were identified as being significant: preoperative NAHS, body mass index (BMI), age, lateral joint space, alpha angle, revision hip arthroscopy, and acetabular microfracture. These 7 variables were also predictive in the bivariate analysis. CONCLUSION: This study reports favorable midterm clinical outcomes in the largest cohort of hip arthroscopies with minimum 5-year follow up in the literature to date. Seven variables were identified as being significant predictors in both the bivariate and multivariate analysis: preoperative NAHS, body mass index (BMI), age, lateral joint space, alpha angle, revision hip arthroscopy, and acetabular microfracture. Of these, preoperative NAHS, BMI, age, and revision hip arthroscopy were predictive of both 2-year and 5-year postoperative NAHS. These predictive factors may prove useful to clinicians in determining indications for hip arthroscopy and counseling patients on its expected outcomes.