Reliability and Validity of Foot Position Index for Foot Posture Assessment / 中国康复理论与实践

ABSTRACT

Objective:To explore the reliability and validity of Foot Posture Index (FPI) scoring system in evaluating foot posture in China. Methods:From September to October, 2019, two testers (tester 1, tester 2) evaluated the foot posture of 15 adult volunteers (30 legs) aged 20 to 40 years after mastering the FPI-6 scoring system. They were tested first by two testers on the same day, and after two weeks, they were retested by tester 1. The intra-group correlation coefficient (ICC) was calculated to evaluate the test-retest reliability and the inter-tester reliability, and the MedCalc was used to perform the Bland-Altman plot. The correlation between the scores of items and scale was analyzed with Spearman analysis, and the items were analyzed with factor analysis. Results:The ICC of the test-retest and inter-tester reliability of each item and total score of FPI were higher than 0.75. The mean difference in FPI scores between the testers was -0.133 and the limits of agreement was (-1.82, 1.55). All items scores were correlated with the total score (P < 0.05); three factors were extracted with the cumulative contribution more than 80%. Conclusion:The FPI-6 scoring system is reliable and valid, to evaluate foot posture for Chinese.