Paper 08: Predicting Clinically Significant Outcomes in Patients Undergoing Hip Arthroscopy for the Treatment of Femoroacetabular Impingement Syndrome: Five-Year Results in 453 Patients

OBJECTIVES: To determine predictors of clinically significant outcome achievement at a minimum of 5-year follow-up in patients undergoing hip arthroscopy for the treatment of femoroacetabular impingement syndrome with routine capsular closure. METHODS: Data were collected and analyzed from consecutive patients who underwent primary hip arthroscopy with routine capsular closure for the treatment of FAIS from a single fellowship-trained surgeon between January 2012 and December 2018. Baseline data, preoperative patient reported outcome measures (PROMs) and 5- year PROMs including Hip Outcome Score-Activities of Daily Living, HOS-Sports Subscale, international Hip Outcome Tool 12 questions, modified Harris Hip Score and visual analog scale pain were recorded. The minimal clinically important difference (MCID) was calculated using the distribution method while patient acceptable symptom state (PASS), and substantial clinical benefit (SCB) were determined from literature defined values. Bivariate correlations with any MCID achievement, any PASS achievement, and any SCB achievement as well as a principle components analysis for variable reduction were used to create three separate multivariate binary logistic regressions to identify significant predictors of achieving a clinically significant outcome. RESULTS: 453 patients with an average age of 34.3 ± 12.5 and average BMI of 25.5 ± 4.9 and majority female (69.1%) were included in the final analysis. There was a significant improvement in all 5-year functional outcomes when compared to preoperative scores (p<0.001 for all). At a minimum of 5-year follow-up, 82.8% of patients achieved any MCID, 69.8% achieved any PASS, and 58.9% achieved any SCB. A total of 23 patients (5.1%) of the study population underwent revision hip arthroscopy or total hip arthroplasty within the follow-up period. Female sex (Odds Ratio (OR), 2.56 [95% confidence interval (CI), 1.47 to 4.45) was a positive predictor of achieving any MCID while higher Tönnis angle (OR, 0.92 [95% CI, 0.87 to 0.98]), Tönnis grade =1 (OR, 0.34 [95% CI, 0.14 to 0.83]) were negative predictors of achieving any MCID. Higher preoperative HOS-ADL (OR, 1.03 [95% CI, 1.01 to 1.05]) and female sex (OR, 2.01 [95% CI, 1.14 to 3.55]) were positive predictors of PASS. With regards to SCB, running (OR, 2.02 [95% CI, 1.31 to 3.14]) was a positive predictor of achievement while a history of back pain (OR, 0.49 [95% CI, 0.28 to 0.86]) and preoperative chronic pain for greater than 2 years (OR, 0.62 [95% CI, 0.36 to 0.98]), were negative predictors of achievement. CONCLUSIONS: At a minimum of 5-year follow-up, 82.8% of patients undergoing primary hip arthroscopy for the treatment of FAIS achieved any MCID, 69.8% achieved any PASS, 58.9% achieved any SCB. Female sex, higher preoperative PROs, and participation in running were positive predictors of achieving a clinically significant outcome while a higher Tönnis angle, Tönnis grade = 1, preoperative chronic pain, and back pain were negative predictors of achieving a clinically significant outcome.