EP8.17 Periacetabular osteotomy results in favourable short and mid-term patient-reported outcome measures– A study utilising the UK Non-Arthroplasty Hip Registry (NAHR) database

Abstract Purpose This study aimed to assess patient-reported outcome-measures (PROMs) from periacetabular osteotomy at 6 and 12 months post-operatively utilising data from the UK Non-Arthroplasty Hip Registry (NAHR). Methods All PAOs recorded in the UK NAHR up to November 2025 were identified. Exclusions included revision procedures, procedures with concomitant arthroscopy and those without available baseline PROM scores. International Hip Outcome Tool (iHOT)-12, EuroQol-5 Dimensions (EQ-5D) Index and EQ-5D Visual Analogue Scale (VAS) scores were captured pre-operatively and at 6- and 12-months post-operatively. Minimal clinically-important difference (MCID) was assessed for each score based on previous values obtained from NAHR data (iHOT-12 ≥9, EQ-5D VAS ≥11, EQ-5D Index ≥0.12) and substantial clinical benefit (SCB) was assessed for iHOT-12 using ≥28. Results 1625 relevant PAOs were identified. Median age was 28 years (IQR 14) and median BMI was 24.2 (IQR 5.8). 90.5% of patients were female. Median iHOT-12 improved from 28 (IQR 23) at baseline to 56 (IQR 38) at 6-months and 65 (IQR 44) at 12-months. Improvements from baseline to 6 months, baseline to 12 months and 6 months to 12 months were all significant (all p<0.0001). 72.5% (n=573) of patient achieved MCID at 6 months and 79.7% (n=593) of patients achieved MCID at 12 months. 45.2% (n=357) of patients achieved SCB at 6 months whilst 53.1% (n=395) achieved SCB at 12 months. Median EQ-5D VAS score improved from 70 (IQR 30) at baseline to 75 (IQR 25) at 6 months and 77 (IQR 28.8) at 12 months. Improvements from baseline to 6 months, baseline to 12 months and 6 months to 12 months were all significant (all p<0.0006). 33.1% (n=274) of patients achieved MCID for EQ-5D VAS at 6 months, which increased to 36.5% (n=292) at 12 months. Median EQ-5D Index score improved from 0.54 (IQR 37.3) at baseline to 0.69 (IQR 0.19) at 6-months and 0.71 (IQR 0.26) at 12 months. All score changes were again significant (all p<0.0001). 50.7% (n=418) of patients achieved MCID for EQ-5D Index at 6 months, which increased to 57.6% (n=460) at 12 months Conclusion The results from this study demonstrate that statistically-significant improvements from baseline are observed in the short- and mid-term post-operatively following PAO. Further improvement is observed from 6- to 12-months across all PROMs. The majority of patients in this cohort achieved MCID post-operatively for iHOT-12 and EQ-5D Index.