Cross-cultural adaptation, validity, and reliability of Turkish version of Identification of Functional Ankle Instability (IdFAI) scale

Objective: This study aimed to develop the Turkish version of Identification of Functional Ankle Instability (TV_IdFAI) scale and evaluate its validity and reliability.

Methods: A total of 100 participants (54 men and 46 women; 50 volleyball players and 50 sedentary individuals) between 18 and 38 years of age were included this study. The construct validity, reference validity, sensitivity, specificity, and test–retest reliability of TV_IdFAI were evaluated. For the test–retest reliability, the scale was applied to all participants again in 10–14 days. A correlation between the scale scores and test–retest results was examined with intraclass correlation coefficient. To evaluate the construct validity, a factor analysis method was used. For reference validity, a sports physician evaluated all participants and the clinical diagnoses were compared with total score of the scale. Sensitivity and specificity were calculated to evaluate the classification success of the scale with specified cutoff.

Results: TV_IdFAI scale was grouped under two separate factors. It was determined that the variance for factor 1, factor 2 and for scale was 46.68%, 15.70%, and 62.38%, respectively. There was a statistically significant relationship 0.74 (95% CI 0.64–0.84; p<0.001) between the physician’s diagnosis and TV_IdFAI in terms of reference validity. The sensitivity and specificity of TV_IdFAI was 0.61 and 0.80, respectively. The reliability of TV_IdFAI was 0.94 (95% CI 0.92–0.96; p<0.001).

Conclusion: This study shows that TV_IdFAI is a simple, easy to apply, reliable, and valid scale to define functional ankle instability in Turkish population.

Level of Evidence: Level II, Diagnostic study

Cite this article as: Tayfur A, Şendil A, Karakaya J, Ergun N. Cross-cultural adaptation, validity, and reliability of Turkish version of Identification of Functional Ankle Instability (IdFAI) scale. Acta Orthop Traumatol Turc 2020; 54(3): 300-4. DOI: 10.5152/j.aott.2020.03.256.