Validation of the French version of the Self-Administered International Hip Outcome Tool-12 Questionnaire and determination of the Minimal Clinically Important Difference (MCID) in the French speaking population

Patient-Reported Outcomes tools are becoming the gold standard in the evaluation of results in orthopaedic surgery. In 2012, the International Hip Outcome Tool-12 (iHOT-12) was developed. This self-administered questionnaire was designed to address the day-to-day clinical setting with faster completion and easier patient flow. In 2021, a French translation of the iHOT-33 questionnaire, from which the iHOT-12 is derived, proved to be valid. Since there is not data in French regarding iHOT-12, we performed a prospective study aiming to answer: (1) is this French version of the iHOT-12 questionnaire as valid, (2) can the minimal clinically important difference (MCID) value for patients undergoing hip arthroscopy for femoro-acetabular impingement (FAI) be defined? It is hypothesized that the iHOT-12-Fr would be valid and responsive to change in a cohort treated for FAI. Using the COSMIN recommendations, a multicentric prospective cohort study was conducted to evaluate the reliability, validity, responsiveness and MCID of the iHOT-12-Fr. In total, 101 patients were recruited for participation in the project. The reliability of the iHOT-12-Fr questionnaire was assessed with the intraclass correlation coefficient (ICC=0.84) and the internal consistency with a Cronbach's alpha (α=0.86). The standard error of measurement (SEM=6.7) and the smallest detectable change (SDC=1.8) were calculated. Construct validity was evaluated with Pearson's correlation coefficients (r) by comparing the iHOT-12-Fr with the iHOT-33-Fr (r=0.96), the Hip disability and Osteoarthritis Outcome Score-Fr (r=0.68) and Nonarthritic Hip Score-Fr (r=0.82). Responsiveness was shown with a standardized effect size of 1.18, standardized response mean of 0.73, responsiveness ratio of 1.4 and an MCID of 11 points. Metrological qualities of the iHOT-12-Fr are comparable to the original version and other versions translated into different languages. This study proves that the French translation of the iHOT-12 is valid, reliable and compares to the original iHOT-12. IV prospective study.