Validity and reliability of a Dutch version of the Foot and Ankle Ability Measure.

Abstract

The aim of the study was to develop a Dutch language version of the Foot and Ankle Ability Measure (FAAM) and evaluate its measurement properties according to the consensus-based standards for the selection of health measurement instruments (COSMIN) definitions. A forward-backward translation procedure was performed and subsequently the Dutch version of the FAAM was evaluated for its reliability and validity in 369 patients with a variety of foot and ankle complaints. The reliability was assessed by calculating the intraclass correlation coefficients (ICC, test-retest reliability), Cronbach's alpha (internal consistency), the standard error of measurement and the minimal detectable change (MDC). Additionally, this was done for athletes. The construct validity was assessed by the use of Spearman's correlation coefficient between FAAM domains and similar and contradictory domains of the Foot and Ankle Outcome Score, Short Form 36 and the Numeric Rating Scale for pain. The ICC of the subscales ranged from 0.62 to 0.86. Cronbach's alpha's minimum was 0.97. At individual level, the MDC ranged from 23.9 to 44.7 and at group level from 2.77 to 4.32. In the subgroup of athletes, the reliability was higher. The hypothesized correlations of the construct validity were supported by an 80% confirmation rate. The Dutch version of the FAAM met adequate measurement properties, although the reliability is not optimal. The FAAM-Sport subscale is more useful in athletes and the FAAM-Sport % seems not to contribute. In athletes with various foot and ankle symptoms, the FAAM can be used for functional assessment and follow-up at group level. For the general population, the FAAM is less appropriate. Diagnostic study, Level I.