Adaptation and transcultural translation into Spanish of the Identification of Functional Ankle Instability questionnaire

Background: Functional ankle instability can hinder the ability to work and perform leisure tasks. Some questionnaires have been used to identify subjects with ankle instability. The English version of the identification functional ankle instability (IdFAI) questionnaire has been broadly used, but there is not a cross-cultural adaptation into Spanish. Objective: The purpose of this study was to cross-culturally adapt the Identification of Functional Ankle Instability questionnaire to a Spanish speaking population from Spain. Design: Cross-sectional study. Methods: One hundred and four patients with history of lateral ankle sprain completed the Spanish version of this questionnaire and the Spanish version of the Cumberland Ankle Instability Tool. The psychometric properties were measured for structural validity, internal consistency, convergent validity, test-retest reliability, standard error of each measurement, ceiling effect and floor effect. Results: The Spanish version of the Identification of Functional Ankle Instability questionnaire had a strong correlation with the Cumberland Ankle Instability Tool (rho =-0.717) with excellent reliability (ICC = 0.9) and internal consistency (Cronbach's alpha = 0.9). No ceiling or floor effects were detected. Conclusion: The results of the present study show that the Spanish version of the Identification of Functional Ankle Instability questionnaire is a valid and reliable measurement tool that can be use in a Spanish population from Spain with functional ankle instability for clinical and research purposes.