Repeatability of a Multi-Segment Foot Model with a 15-Marker Set in Healthy Children
Authors: Kim Eo Jin , Lee Dong Yeon , Lee Doojae 
Published: October 2016

Category: Basic Sciences/Biologics Introduction/Purpose: Recently, 3D multi-segment foot models using 15 marker set(Foot 3D model) was proposed . Our team demonstrated that this model had comparable intra-session/inter-session repeatability with other MFMs making it suitable for evaluation of segmental foot motion during gait. And also we have shown that this model had high intra-session/inter-session repeatability in the assessment of foot motion in healthy adults. Compared with adults, children have some specific character of gait. Mechanical axis of lower extremity and gait has changed over the course of growing up. And children has small bones and soft skin comparing with adults, so these can be some factors that induce bias of analysis. Then despite of verification of high intra- session/inter-session repeatability of Foot 3D model in healthy adults, it is necessary to validate the intra-session/inter-session repeatability of this model in healthy children. Methods: Participating subjects is made up of 40 feet of twenty healthy children (10 males, 10 females) of 10-15 years old. We utilized multi-segment foot model with 15-marker set used in previous study for healthy adults. We divided participants into two groups in tens. One group was tested by same operator in each test and the other group changed the operator in each test. The former is for inter-session analysis and the latter is for inter-rater analysis. In this study, we analyzed the intra-session, inter- session, and inter-rater repeatability. Coefficients of multiple correlation (CMC) and intra-class correlation (ICC) were calculated in order to assess the intra-session, inter-session and inter-rater session repeatability. The difference between the two sessions of each group was assessed for each time points of the gait cycle. Results: There is no significant difference pattern in gait analysis graph (Figure 1). The mean intra-session CMC (±Standard deviation) was 0.933 (± 0.034). The intra-session CMC values of all parameters were interpreted as excellent or very good repeatability. The intra-session ICC values of all parameters were interpreted as excellent. The mean inter-session CMC (±SD) was 0.794 (± 0.123). The mean inter-session ICC (±SD) was 0.866 (± 0.086). The inter-session ICC values of all parameters were interpreted as excellent except hindfoot rotation parameter. Inter-rater CMC (±Standard deviation) was 0.766 (± 0.214). The mean inter-rater ICC (±SD) was 0.839 (± 0.203). The inter-rater ICC values of all parameters were interpreted as good or excellent. Mean gap of all parameters is larger than the value of previous study for healthy adults. Conclusion: In this study, we used a multi-segment foot models using 15 marker set in order to evaluate segmental foot motion in healthy children as in case of adults. And we demonstrated that this model had high intra-session, inter-session and inter-rater repeatability in the assessment of foot motion except some cautions. We believe that our study for children is very important to understand the gait of childhood and this Foot 3D model can be applicable in clinical settings, which require further elucidation.