Cross-cultural adaptation and validation of Spanish version of The Foot and Ankle Ability Measures ( FAAM-Sp)

Background: The Foot and Ankle Ability Measure (FAAM) is a Patient Reported Outcome (PRO) commonly used to determine the effectiveness of therapeutic interventions for patients with foot and ankle pathologies and associated impairments of body function and structure, activity limitations, and participation restrictions. The aim of this study was to cross-culturally adapt the FAAM into Spanish. Methods: Cross-cultural adaptation was performed according to the international guidelines of the International Society for Pharmacoeconomics and Outcomes Research. Cronbach's alpha, test re-test reliability, and item-total and inter-item correlations were analyzed. Confirmatory factor analysis (CFA) was carried out to test construct validity. Pearson correlations were calculated to assess the convergent validity between FAAM and EuroQol-5. Results: Spanish data set comprised 194 patients, with a mean age of 38.45 (16.04) and 130 (67.1%) were female, seeing a podiatrist with a wide variety of foot and ankle related disorders. CFA was carried out to test structure matrix (which has three factors). The test-retest reliability was high with global ICC of 0.95 (95% CI: 0.93 to 0.98). A 15 items version of the FAAM-Sp Activities of Daily Living (ADL) obtained the best fit: relative chi-square (x(2)/df) of 2.46, GFI 0.90 CFI 0.95, NFI 0.93, and RMSEA 0.08 (90% CI 0.04 to 0.09). For exploratory factor analysis for the FAAM-Sp Sport, a one factor solution was obtained, which explained 76.70% of total variance. CFA corroborated this model with an excellent goodness of fit:: relative chi-square (x(2)/df) of 0.80, GFI 0.99 CFI 1.00, NFI 0.99, and RMSEA 0.00 (90% CI 0.00 to 0.75). Conclusions: This study validated a new 15-item FAAM-Sp ADL and FAAM-Sp Sport subscales, which can be used as a self-reported outcome measure in clinical practice and research for patients resident in Spain whose main language is Spanish.