Frontiers in Bioengineering and Biotechnology (Jan 2023)

Reliability of foot posture index (FPI-6) for evaluating foot posture in patients with knee osteoarthritis

  • Yi Wang,
  • Zehua Chen,
  • Zugui Wu,
  • Junyi Li,
  • Congcong Li,
  • Jiaman Yang,
  • Weijian Chen,
  • Zixuan Ye,
  • Xinxin Shen,
  • Tao Jiang,
  • Wengang Liu,
  • Xuemeng Xu,
  • Xuemeng Xu

DOI
https://doi.org/10.3389/fbioe.2023.1103644
Journal volume & issue
Vol. 11

Abstract

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Objective: To determine the reliability of FPI-6 in the assessment of foot posture in patients with knee osteoarthritis (KOA).Methods: Thirty volunteers with KOA (23 females, 7 males) were included in this study, assessed by two raters and at three different moments. Inter-rater and test-retest reliability were assessed with Cohen’s Weighted Kappa (Kw) and Intraclass Correlation Coefficient (ICC). Bland-Altman plots and respective 95% limits of agreement (LOA) were used to assess both inter-rater and test-retest agreement and identify systematic bias. Moreover, the internal consistency of FPI-6 was assessed by Spearman’s correlation coefficient.Results: FPI-6 total score showed a substantial inter-rater (Kw = .66) and test-retest reliability (Kw = .72). The six items of FPI-6 demonstrated inter-rater and test-retest reliability varying from fair to substantial (Kw = .33 to .76 and Kw = .40 to .78, respectively). Bland-Altman plots and respective 95% LOA indicated that there appeared no systematic bias and the acceptable agreement of FPI-6 total score for inter-rater and test-retest was excellent. There was a statistically significant positive correlation between each item and the total score of FPI-6, which indicated that FPI-6 had good internal consistency.Conclusion: In conclusion, the reliability of FPI-6 total score and the six items of FPI-6 were fair to substantial. The results can provide a reliable way for clinicians and researchers to implement the assessment of foot posture in patients with KOA.

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