A high proportion of patients demonstrate recall bias in the retrospective collection of patient-reported outcomes following hip arthroscopy

The aim of this study is to assess agreement between retrospectively and prospectively collected patient-reported outcome measures (PROMs) following hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Patients undergoing hip arthroscopy from 2021 to 2023 for FAIS completed preoperative PROMs, including the modified Harris Hip Score (mHHS) and the Non-Arthritic Hip Score (NAHS). Post-operatively, patients were surveyed and asked to recall their preoperative hip function. Paired two-sample t tests were used to compare baseline and recalled baseline PROMs and the difference between scores was compared to previously published minimally clinically important difference (MCID) values. Intraclass correlation coefficients (ICCs) were calculated to test the reliability between scores based on a single-rater, two-way mixed-effects model. Multivariable regression, accounting for age, sex and preoperative baseline scores, was used to evaluate the relationship of time elapsed since surgery with recall accuracy. A total of 116 patients (age: 37.6 ± 11.8 years; 61.2% female) were included. The mean time elapsed for recalled data was 13.1 months (range: 1-27 months). Overall, patients' recalled scores were significantly lower than those prospectively collected (mHHS: 52.9 ± 20.1 vs. 61.5 ± 18.5, p