FP15.6 Increasing BMI associated with poorer predicted post-operative patient-reported outcome measures at 12 months following hip arthroscopy for femoroacetabular impingement – A national registry study

Abstract ICLB15 - The Preservation Scorecard: Fundamentals of Tracking Outcomes and Standardizing Recovery, Session Room 12 (BMCC Level 3), October 9, 2026, 14:00 - 16:00 Introduction This study aimed to assess the impact of body mass index (BMI) on post-operative patient-reported outcome measures (PROMs) from hip arthroscopy (HA) for femoroacetabular impingement (FAI). Materials and Methods All HA performed for FAI were identified in the UK Non-Arthroplasty Hip Registry (NAHR) database between January 2012 and November 2025. International Hip Outcome Tool (iHOT)-12, EuroQol- 5 Dimension (EQ-5D) Visual Analogue Scale (VAS) and EQ-5D Index scores were captured pre-operatively and at 6- and 12-months post-operatively. Multiple linear regression (MLR), adjusting for age, sex and baseline score, ANOVA and Tukey’s Highly Significant Difference (HSD) pairwise models were used to assess trends in absolute PROM score as well as score improvement from baseline on a continuous and categorical basis, utilising World Health Organisation (WHO) BMI categories. Results 2845 HA with available BMI values were identified. The majority of patients were “Healthy” BMI (50.2%, n=1427) or “Overweight” (34.7%, n=986). Increasing BMI was a predictor for poorer absolute outcomes at 12-months post-operatively for iHOT-12 (-0.49 [SE 0.19], p=0.0096), EQ-5D VAS (-0.68 [SE 0.15], p<0.0001) and EQ-5D Index (-0.0043 [SE 0.0016], p=0.0064). A non-significant trend was also noted at 6-months post-operatively for EQ-5D VAS (-0.23 [SE 0.13], p=0.0796). ANOVA of BMI groups demonstrated significant associations of BMI with outcome at 6- and 12-months post-operatively for all PROMs (all p≤0.015). Increasing BMI predicted greater post-operative EQ-5D Index score improvement at 6-months (0.0033 [SE 0.0015], p=0.0270), but was not demonstrated at 12-months (p=0.5130) on continuous analysis. No association between iHOT-12 or EQ-5D VAS was demonstrated. No association between WHO BMI category and PROM score improvement were demonstrated on ANOVA. Conclusion This study has demonstrated a modest but significant association between increasing BMI and poorer absolute post-operative PROM scores at 12-months, as well as a significant association between WHO BMI category and absolute post-operative PROM scores in patients undergoing HA for the management of FAI. Patients with increased BMI demonstrated greater EQ-5D Index score improvement at 6 months post-operatively compared to Healthy weight patients, but these improvements were lost by 12 months.