TP3.7 Clinically Meaningful Outcomes for the Modified Harris Hip Score and Nonarthritic Hip Score Following Hip Arthroscopy for Femoroacetabular Impingement Syndrome at 15-Year Follow-up

Abstract

Abstract Purpose To define the minimal clinically important difference (MCID), patient acceptable symptom state (PASS), and substantial clinical benefit (SCB) for the modified Harris Hip Score (mHHS) and Nonarthritic Hip Score (NAHS) at mean 15 years after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Methods Patients who underwent primary hip arthroscopy for FAIS by a single surgeon from June 2007 to December 2011 were retrospectively reviewed. The mHHS and NAHS were collected at baseline and 1, 5, 10, and 15 years postoperatively. The MCID and SCB were calculated at each time point using the distribution-based method (0.5 and 1.0 SD of the change score, respectively). The PASS was derived as the 25th percentile of absolute 15-year scores among MCID achievers. Associations between baseline characteristics and threshold achievement were assessed with Firth penalized logistic regression. Results Ninety-eight patients were included (mean age, 37.4 ± 11.3 years; 58.2% female). At 15 years, the MCID, PASS, and SCB were 8.8, 88.8, and 17.5 for mHHS and 9.1, 89.7, and 18.3 for NAHS. Increased BMI was associated with decreased achievement of the mHHS MCID (OR, 0.81; P = 0.027), PASS (OR, 0.86; P = 0.004), and SCB (OR, 0.80; P = 0.005), and NAHS MCID (OR, 0.81; P = 0.019) and SCB (OR, 0.88; P = 0.044). Increasing age predicted decreased achievement of the NAHS PASS (OR, 0.96; P = 0.048). Ceiling effects were observed, with 57.1% of patients achieving the maximum mHHS and 46.9% the maximum NAHS. Conclusions This study establishes the longest-term MCID, PASS, and SCB thresholds reported for the mHHS and NAHS following hip arthroscopy for FAIS, with a time-dependent increase in MCID across time points. The NAHS demonstrated lower ceiling effects than the mHHS, supporting its utility as a more sensitive long-term PRO measure.