Hindfoot Kinematics of Healthy Subjects Using Lateral Wedge Insoles in a Biplane Fluoroscopy System

Abstract

Lateral wedge insoles (LWIs) are a type of orthosis used to reduce the external knee adduction moment (EKAM), which is associated with the development and progression of tibiofemoral osteoarthritis. However, their effect on kinematics at the hindfoot is unclear. Biplane fluoroscopy was utilized to measure the kinematics of the tibia, talus, and calcaneus, for a pilot study to demonstrate the feasibility of data collection and analysis. To motivate the study, a literature review of LWIs was first performed, including discussion of EKAM, hindfoot moment, dose response, pain scores and more. A LabVIEW Real-Time system was implemented to upgrade the biplane system to add stance phase timing and additional features. Three subjects were studied in the biplane system with four insole conditions. The calcaneus tended to dorsiflex and invert as stance phase progressed. This study demonstrated that the protocol and data analysis are viable and more subjects can be analyzed.