Reliability of a high accuracy image-based system for 3D modelling of the medial longitudinal arch during gait

Abstract

he Medial Longitudinal Arch (MLA) is the largest arch of the foot and is regarded as the most important foot arch in clinical foot assessments due to its influence on lower limb function, foot stability and foot pain. Each foot is classified as either high arched, low arched or normally arched depending on the structure of the MLA. There are currently a number of techniques that are used to classify the foot in a static state based on measurements of the MLA. These static measurements are then used to predict the behaviour of the foot arch in a dynamic state. However, it is easy to identify limitations with these techniques as the shape of the MLA in a static state cannot predict the behaviour of the MLA during dynamic activities. Therefore, the aim of this chapter is to introduce a high accuracy 3D modelling system that has been developed to map the shape of the MLA during gait using high definition video camcorders. The objectives of the study were hence: (1) to determine whether changes can be detected along the MLA for different weight bearings during gait, (2) to test the accuracy and reliability of the developed imaging system for creating dynamic 3D models of the foot arch and (3) to determine the quality and suitability of the 3D model. The results of the study show that changes can be detected along the MLA during gait with a level of accuracy of less than 0.4 mm when a 3D model of the foot is generated in PhotoModeler Scanner.