Date of Award

Spring 2015

Document Type

Thesis

First Advisor

McCullough, Matthew B.A.

Abstract

Medial tibial stress syndrome (MTSS) is an overuse injury in the lower extremity associated with endurance running. MTSS is a palpitation of pain of at least 5 centimeters along the medial tibia with possible microfractures in the tibia. The various risk factors which may lead to the development of MTSS are body mass index, over pronation, heel striking, level of shod in the running shoe, type and angle of running surface, high volume training, age, gender, stride length, range of motion, and calf girth. Few investigations have been made to limit these risk factors through the utilization of finite element analysis (FEA). This study investigates the likelihood of MTSS developing and the possibility of microfractures in the tibia under varying conditions of pronation degree, body mass index, material property, and gait phase. FEA was used in order to measure the von Mises stress of 24 human tibia models. The simulations were run for three main phases of gait “impact”, “mid-stance”, and “push-off”. The risk factors under investigation were intrinsic in nature, which are over pronation (OP) and body mass index (BMI). Forces were input for 2 male subjects running at 8 miles per hour on a flat surface. Simulations were run for isotropic and orthotropic tibia models with “normal pronation and normal BMI”, “over pronation and normal BMI”, “normal pronation and high BMI”, and “over pronation and high BMI”. FEA revealed that the combination of over pronation and high BMI consistently had the greatest von Mises stresses throughout each phase of gait for isotropic and orthotropic tibia models. Statistical results show that material properties had the greatest effect on the measured von Mises stress followed by pronation degree, gait phase, and BMI. A normality test with a confidence interval of 95% proved that the distribution of von Mises stress across was acceptable for all models with P=0.130. Factorial ANOVA was run for gait phase, BMI, pronation degree, and material property, which also confirmed the greatest effects on von Mises stress are material property, pronation degree, gait phase, and then BMI.

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