Validity and reliability of the French translation of the Identification of Functional Ankle Instability (IdFAI).

Abstract Purpose To translate and validate the Identification of Functional Ankle Instability (IdFAI) into French. Methods The IdFAI was translated according to international recommendations. Discriminative power, floor and ceiling effects, construct validity (including confirmatory factorial analysis (CFA)), internal consistency and test-retest reliability were measured. Standard Error of Measurement (SEM) and Smallest Detectable Change (SDC) were also calculated. Results 160 participants were included. The IdFAI-F showed a very good test-retest reliability (ICC = 0.95). The SEM was 1.37 and the MDC was 3.79. The internal consistency was moderate (Cronbach's alpha coefficient = 0.68). The correlation between the IdFAI and the Cumberland Ankle Instability Tool (CAIT) was high (r = −0.75, p  Conclusions The IdFAI-F is a valid and reliable tool to accurately identify and measure chronic ankle instability in research and clinical settings for French-speaking individuals.