TP8.6 Impact of Symptom Duration on 2-, 10-, and 15-Year Outcomes After Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome

Abstract

Abstract Background The prognostic value of preoperative symptom duration after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) is unclear and existing research is varied in perspectives. Hypothesis/Purpose The purpose of this study was to determine whether preoperative symptom duration predicted patient-reported outcomes (PROs) and minimal clinically important difference (MCID) achievement at 2, 10, and 15 years after primary hip arthroscopy for FAIS. We hypothesized that patients with longer intervals between symptom start and surgical intervention would have worse short-term and long-term outcomes. Methods Patients undergoing primary hip arthroscopy at a single academic institution were prospectively enrolled and retrospectively reviewed. Exclusion criteria were age <15 years, revision surgery, presence of inflammatory arthritis, Tönnis grade ≥2, BMI <18.5 kg/m2). Patients were included if they had documented symptom duration, modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) at baseline, and at least 1 post-operative mHHS and NAHS at 2, 10, or 15 years. Symptom duration was modeled per 6-month increase and by cutoffs (<6 months, <1 year, <2 years, and ≥5 years). MCID achievement for mHHS and NAHS was determined using a distribution-based method and evaluated with logistic regression. Baseline-adjusted and multivariable linear regression models evaluated postoperative mHHS and NAHS, longitudinal mixed-effects models assessed associations across follow-up time points, and logistic regression evaluated revision and total hip arthroplasty (THA) endpoints. Effect modification by age, BMI, Tönnis grade, and Outerbridge grade was assessed using multiplicative interaction terms with symptom duration. Results A total of 185 hips were eligible for analysis. Mean age was 39.1 ± 12.3 years, mean BMI was 25.4 ± 4.1 kg/m2, and mean symptom duration was 24.5 ± 29.6 months. In the overall cohort, increased symptom duration was not independently associated with mHHS at 2, 10, or 15 years (ß=-0.02, p=0.899; ß=-0.18, p=0.494; ß=0.01, p=0.950) or NAHS (ß=0.07, p=0.613; ß=-0.10, p=0.725; ß=0.05, p=0.814) in covariate-adjusted models. Prespecified and exploratory cutoff analyses likewise showed no significant overall threshold effect. Mixed-effects models showed no overall effect with time interaction. A significant Outerbridge grade by symptom-duration effect was observed: Outerbridge grade ≥1 strengthened the negative symptom-duration association at 2 years for mHHS (interaction ß=-1.58, p=0.002) and NAHS (interaction ß=-2.27, p<0.001), and grade ≥2 modified 15-year NAHS (interaction ß=-4.04, p=0.004). Conclusion Preoperative symptom duration was not independently associated with worse 2-, 10-, or 15-year PROs after primary hip arthroscopy for FAIS. Pre-existing chondral damage may magnify the adverse effect of longer symptom duration in selected subgroups.