Structural validity of the foot and ankle outcome score for orthopaedic pathologies with Rasch Measurement Theory

Krista Tapaninaho, Antti J. Saarinen, Outi Ilves, Mikko M. Uimonen, Arja H. Häkkinen, Henrik Sandelin, Jussi P. Repo

Research output: Contribution to journalArticlepeer-review

Abstract

Background: The Foot and Ankle Outcome Score (FAOS) is one of the most frequently used patient-reported outcome measures for foot and ankle conditions. The aim is to test the structural validity of the Finnish version of the FAOS using Rasch Measurement Theory. Methods: FAOS scores were obtained from 218 consecutive patients who received operative treatment for foot and ankle conditions. The FAOS data were fitted into the Rasch model and person separation index (PSI) calculated. Results: All the five subscales provided good coverage and targeting. Three subscales presented unidimensional structure. Thirty-eight of the 42 items had ordered response category thresholds. Three of the 42 items had differential item functioning towards gender. All subscales showed sufficient fit to the Rasch model. PSI ranged from 0.73 to 0.94 for the subscales. Conclusions: The Finnish version of the FAOS shows acceptable structural validity for assessing complaints in orthopaedic foot and ankle patients.

Original languageEnglish
JournalFOOT AND ANKLE SURGERY
DOIs
Publication statusE-pub ahead of print - 16 Mar 2021
Publication typeA1 Journal article-refereed

Keywords

  • Psychometric properties
  • Quality of life
  • Validity

Publication forum classification

  • Publication forum level 1

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

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