Predictors of Clinical Outcomes After Hip Arthroscopy: A Prospective Analysis of 1038 Patients With 2-Year Follow-up

Abstract

Background: As hip arthroscopy has expanded in popularity and volume, more information is needed about indications for the procedure and the predictive factors of clinical outcomes. Purpose: To evaluate clinical outcomes of hip arthroscopy in a prospective study and to analyze the cohort to identify factors that are predictive of improvement. Study Design: Case-control study; Level of evidence, 3. Methods: Data were collected prospectively on all patients undergoing hip arthroscopy between February 2008 and June 2012. We included all patients undergoing hip arthroscopy who agreed to participate and who completed 4 patient-reported outcome (PRO) instruments at a minimum 2-year follow-up: the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score–Activities of Daily Living (HOS-ADL), and Hip Outcome Score–Sport-Specific Subscale. The NAHS was selected as our primary outcome instrument. All patients with any previous hip conditions were excluded. We analyzed 34 preoperative and intraoperative variables using bivariate and multivariate analyses compared with NAHS. Results: The cohort consisted of 1038 patients with a mean follow-up of 30.1 months (range, 24.0-61.2 months). Mean age was 36.4 years (range, 13.2-76.4 years). All postoperative PRO scores showed significant improvement ( P < .001) at 2 years compared with preoperative scores. Bivariate analysis identified 15 variables (7 categorical and 8 continuous) and multivariate analysis identified 10 variables that were predictive of 2-year postoperative NAHS. Preoperative NAHS, preoperative HOS-ADL, preoperative mHHS, age, duration of symptoms, body mass index (BMI), and revision hip arthroscopy were identified as predictive factors in both bivariate and multivariate analyses. The predictive value of preoperative NAHS was accentuated for patients with higher BMI. Conclusion: This study reports favorable clinical outcomes in the largest cohort of hip arthroscopies with a minimum 2-year follow-up in the literature to date. Factors identified as predictive in both bivariate and multivariate analyses included preoperative NAHS, HOS-ADL, and mHHS; age; duration of symptoms; BMI; and revision hip arthroscopy. These predictive factors may be useful to the clinician in determining prognosis and operative indications for hip arthroscopy.