Adaptation and psychometric evaluation of the simplified Chinese version of the Identification of Functional Ankle Instability questionnaire in Chinese-speaking patients with chronic ankle instability disorders

Abstract

Background: This study aimed to adapt the Identification of Functional Ankle Instability (IdFAI) questionnaire into simplified Chinese version and assess its reliability, validity, and responsiveness in Chinese-speaking patients with chronic ankle instability (CAI) disorders. Methods: The simplified Chinese version of the IdFAI (SC-IdFAI) questionnaire was developed in a five-step procedure of cross-cultural translation and adaptation. Three questionnaires, including the SC-IdFAI, Medical Outcomes Study Short-Form 36 (SF-36), and Foot and Ankle Ability Measure (FAAM), were administered to the recruited patients. Then, the Cronbach’s alpha, intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change (MDC), Spearman’s correlation coefficient (rs), effect size (ES), and standardized response mean (SRM) were calculated to evaluate the reliability, validity, and responsiveness of the SC-IdFAI questionnaire. Results: A total of 131, 119, and 86 patients with CAI successfully completed the first, second, and third rounds of the questionnaires, respectively. Good or excellent internal consistency and test–retest reliability were found in the overall scale and subscales of the SC-IdFAI questionnaire. Low values for SEM (1.346) and MDC (3.73) indicated that small clinical changes could be detected by the SC-IdFAI questionnaire. The correlations of SC-IdFAI with FAAM and SF-36 were generally in agreement with a priori hypotheses (85%, 34/40), suggesting good construct validity of the SC-IdFAI questionnaire. Moreover, good responsiveness was observed in the overall scale and subscales of the SC-IdFAI questionnaire. Conclusion: The SC-IdFAI questionnaire was reliable, valid, and responsive for evaluating Chinese-speaking patients with CAI and might prove to be an effective instrument.