Abstract

Introduction: The concept of the Minimal Clinically Important Difference (MCID) and Substantial Clinical Benefit (SCB) are thresholds in the assessment of clinical outcomes. Defined as the smallest change in a treatment outcome that a patient would identify as important, MCID establishes a threshold for clinical significance, beyond the mere statistical difference while SCB is considers as threshold for substantial improvement. Using the British Hip Society Non-Arthroplasty Hip Registry, this study aimed to validate the MCID for the international Hip Outcome Tool 12 (iHOT12), a tool designed to measure changes in patient-reported outcome measures (PROMS) following arthroscopic intervention for Femoroacetabular impingement (FAI). Method: The study analysed the data of 5590 patients recorded in the NAHR who underwent primary hip arthroscopic treatment for FAI between November 2013 and July 2023. Using the change in score between baseline and follow up a MCID threshold of 13 point gain, and a SCB score of 28 as defined previously (Holleyman et al), the change in score in NAHR records was evaluated to establish the viability of these thresholds Results: Of the eligible patients, 43.8%% (2450) had completed both the baseline iHOT12 survey and follow-up survey at 1 year. The average iHOT12 score at baseline and 1 year 32.69 (17.79 SD) and 58.54 (27.79) respectively. The number of patients who achieved the threshold for MCID were 1587 (64.7%), and for SCB were 1128 (46%). Conclusion: The results of our study affirm the MCID and SCB values reinforce the relevance of distribution-based methods in defining clinically significant changes in iHOT12 score. Based on our findings, we advocate for the adoption of a MCID values of 13.6 and a SCB of 28 when utilising the iHOT12 score in determining acceptable outcomes. This recommendation is grounded in the need for a practical and clinically meaningful threshold that resonates with patient perception of change.