Development of new foot model for dynamic equinus foot behavior during gait

Abstract

The evaluation of foot deformities in the gait laboratory is still a challenge for many rehabilitation centers. Several models have been proposed in measuring accentuated foot deformities, however there are some limiting factors for the markers placement, the number of markers used, as well as the complexity of their placement which limit the data collection. The aim of this study is to develop a new foot model to measure the dynamic behavior of an equinus foot during gait. Using only four additional markers, our model is built over the original VICON Plug-In-Gait marker protocol, not compromising the time spend to set up the subject for the conventional gait analysis. The outcomes of the measurements are the angle displacements of two regions of both feet: hindfoot and forefoot. It is notable that the values of the angles of the hindfoot and forefoot planes are not zero when the individual is in neutral stance. Therefore compensation is needed using calibration data of unimpaired subjects. The model proposed was tested in an unimpaired subject as well in a patient scheduled for gait exam with right foot equinus. Our results show promising information about the equinus deformity during gait, but further research is needed to indicate the precision of the tool, especially in subjects with stair type equinus.