French validation of the Foot Function Index (FFI).
OBJECTIVE
French validation of the Foot Function Index (FFI), self-questionnaire designed to evaluate rheumatoid foot according to 3 domains: pain, disability and activity restriction.


METHODS
The first step consisted of translation/back translation and cultural adaptation according to the validated methodology. The second stage was a prospective validation on 53 patients with rheumatoid arthritis who filled out the FFI. The following data were collected: pain (Visual Analog Scale), disability (Health Assessment Questionnaire) and activity restrictions (McMaster Toronto Arthritis questionnaire). A test/retest procedure was performed 15 days later. The statistical analyses focused on acceptability, internal consistency (Cronbach's alpha and Principal Component Analysis), test-retest reproducibility (concordance coefficients), external validity (correlation coefficients) and responsiveness to change.


RESULTS
The FFI-F is a culturally acceptable version for French patients with rheumatoid arthritis. The Cronbach's alpha ranged from 0.85 to 0.97. Reproducibility was correct (correlation coefficients>0.56). External validity and responsiveness to change were good.


CONCLUSIONS
The use of a rigorous methodology allowed the validation of the FFI in the French language (FFI-F). This tool can be used in routine practice and clinical research for evaluating the rheumatoid foot. The FFI-F could be used in other pathologies with foot-related functional impairments.
Unité de nutrition humaine, INRA, UMR 1019, CRNH, service de medecine physique et readaptation, universite d'Auvergne, CHU Clermont-Ferrand, 63000 Auvergne, France.
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Pourtier-Piotte
Unité de biostatistique, délégation recherche clinique et innovation, CHU Clermont-Ferrand, France.
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Pereira
Service de rhumatologie, université d'Auvergne, CHU Clermont-Ferrand, France.
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Soubrier
Boucharenc Podo-orthésiste, Saint Chely d'Apcher, France.
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Thomas
Service d'épidémiologie, économie de la santé et prévention, CHU Clermont-Ferrand, France.
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Gerbaud
Unité de nutrition humaine, INRA, UMR 1019, CRNH, service de medecine physique et readaptation, universite d'Auvergne, CHU Clermont-Ferrand, 63000 Auvergne, France. Electronic address: ecoudeyre@chu-clermontferrand.fr.
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Coudeyre
D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000503:physiopathology*; D004185:Disability Evaluation; D005260:Female; D005534:Foot Diseases / Q000209:etiology / Q000503:physiopathology*; D005602:France; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D014175:Translating
Foot; Functional impairment disability; Rheumatoid arthritis; Validation