Recall Bias in the Retrospective Collection of Common Patient-Reported Outcome Scores in Hip Arthroscopy

Abstract

Background: The use of patient-reported outcomes (PROs) is common practice in the treatment of patients undergoing hip arthroscopy. While the prospective collection of PROs is preferred, retrospective collection involving patient recall is not uncommon and may be subject to bias. Purpose: To assess the presence of recall bias between prospectively and retrospectively collected PRO scores in hip arthroscopy. Study Design: Cohort study; Level of evidence, 2. Methods: Patients who underwent hip arthroscopy between 2015 and 2021 and provided preoperative baseline responses for the International Hip Outcome Tool–12 (iHOT-12), the Hip disability and Osteoarthritis Outcome Score–Physical Shortform (HOOS-PS), and the modified Harris Hip Score (mHHS) were eligible for recruitment. After surgery, participants were asked to complete a study-specific survey and the same preoperative PROs retrospectively. Agreements between the prospective and retrospective scores were assessed, and associations between score discrepancies and patient characteristics were identified. Results: A total of 94 patients (43.3% participation rate) completed study requirements and were included for analysis. The mean ± standard deviation duration of symptoms before surgery was 25.3 ± 32.8 months, and the mean duration to recall (from the day of surgery) for the PROs was 29.6 ± 22.2 months. The iHOT-12 (intraclass correlation coefficient [ICC], 0.409; P < .001) and HOOS-PS (ICC, 0.415; P < .001) scores had low agreement between prospectively and retrospectively collected scores. The mHHS showed moderate agreement (ICC, 0.598; P < .001). The mean scores for the iHOT-12 (41.4 ± 22.6 vs 34.6 ± 16.3; P < .01), HOOS-PS (29.7 ± 18.5 vs 40.9 ± 17.1; P < .001), and mHHS (62.7 ± 16.5 vs 54.5 ± 14.8; P < .001) were all significantly different prospectively versus retrospectively. The average changes in score for the iHOT-12, HOOS-PS, and mHHS were −6.8, 11.2, and −8.2, respectively. Duration to recall and female sex were predictors of the difference between prospectively and retrospectively collected iHOT-12 data, while no predictors were significant for the HOOS-PS or mHHS. Conclusion: The retrospective collection of PROs for hip arthroscopy procedures is subject to bias. On average, retrospective (recalled) PROs reflected worse pain/function than their prospectively recorded counterpoints; therefore, retrospective patient recall is an unreliable source of clinical data, and the prospective collection of iHOT-12, mHHS, and HOOS-PS data should be prioritized.