EP8.16 Intra-articular hyaluronidase administration associated with improved 6- and 12-month outcomes following hip arthroscopy for femoroacetabular impingement – A national registry study

Abstract

Abstract Purpose This study assessed the impact of intra-articular hyaluronidase administration during hip arthroscopy for femoroacetabular impingement (FAI) on post-operative patient-reported outcome measure (PROM) scores. Methods All patients who underwent excision of a FAI lesion recorded in the UK Non-Arthroplasty Hip Registry (NAHR) up to November 2025 were identified. Exclusion criteria included concurrent osteotomy, revision procedure and no available baseline and at least one follow up PROM. Cases were then divided into ‘hyaluronidase’ and ‘no hyaluronidase’ groups. PROMs analysed were iHOT-12, EQ-5D Index and EQ-5D Visual Analogue Scale (VAS). Multivariable regression models were fitted and outcomes at 6 and 12 months were analysed independently on a complete-case basis using robust standard errors, excluding BMI due to low completion rate (47.9%), as well as using multiple imputation of covariates including BMI with m=20 and Rubin’s rule for pooling. Results The ‘hyaluronidase’ group (n=141) demonstrated significantly greater median age (38vs34, p<0.001), a significantly greater proportion of cam lesions (75%vs63%, p=0.002) and a significantly greater proportion of Outerbridge Grade 0 patients (93%vs71%, p<0.001) compared with the ‘no hyaluronidase’ group (n=447). No differences in baseline PROMs, BMI, sex distribution or degree of acetabular cartilage damage was observed (all p>0.05). Complete-case analysis demonstrated significantly greater 12 month iHOT-12 (10.5 [SE 3.9], p=0.0082), 6- (4.8 [SE 1.9], p=0.0104) and 12-month (7.0 [SE 2.7], p=0.0096) absolute EQ-5D VAS score, 6- (5.9 [SE 2.5], p=0.0191) and 12-month (8.2 [SE 3.4], p=0.0174) EQ-5D VAS score improvement and 12 month absolute score (0.103 [SE 0.031], p=0.0012) and 12 month score improvement (0.084 [SE 0.036], p=0.0213) for EQ-5D Index. Imputed analysis demonstrated significant improvement in absolute 12-month EQ-5D Index score with hyaluronidase use (0.084 [SE 0.036], p=0.0213). A non-significant trend towards greater 12-month iHOT-12 score improvement was also noted on complete-case analysis (7.4 [SE 4.3], p=0.0879). Conclusion Results from this study suggest that intra-articular hyaluronidase administration is associated with significantly improved absolute outcomes and score improvement from baseline at 6 and 12 months post-operatively. Results should be interpreted with caution given exclusion of BMI in complete-case analysis and high degree of imputation in imputed analysis.