Reliability and validity of the Turkish version of the Foot Function Index in patients with foot disorders
Reliability and validity of the Turkish version of the Foot Function Index in patients with foot disorders
Background/aim: The Foot Function Index (FFI) is a valid, reliable, and widely used self-reported questionnaire for the foot. Thepurpose of this study was to provide evidence for the validity and reliability of the Turkish version of the FFI (FFI-TR) among patientswith foot disorders such as plantar fasciitis, hallux valgus, pes planus, and hammertoe deformities.Materials and methods: One hundred and fifty-nine patients with foot disorders were enrolled. The psychometric properties of thepreviously translated and adapted FFI-TR were assessed. The internal consistency and test–retest reliability were evaluated. Constructvalidity was examined for correlations with the Short Form-36 (SF-36) questionnaire.Results: Cronbach’s alpha ranged between 0.821 and 0.938. Reproducibility was satisfactory, with intraclass correlation coefficient valuesbetween 0.960 and 0.985. Weak correlations were found between FFI-TR and some SF-36 subscales for validity (|rho| < 0.30). Therewas a ceiling effect for the activity limitation subscale. There were no floor effects for any items or application times. Good accuracy wasdetermined for all scores.Conclusion: FFI-TR is a reliable and valid scale. This tool can be used in routine practice and clinical research for evaluating footdisorders and foot-related functional impairments.
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