Study of Stress Distribution in the Tibia During Stance Phase Running Using the Finite Element Method

Abstract

Tibia fractures are common in the elderly who have osteoporosis. Stress distributions in the tibia of two osteoporosis patients were studied to investigate the cause of this fracture and the effects of contact areas on the distal end of the tibia, body weight and knee flexion angles on the tibial stresses were determined using finite element analysis. Three-dimensional tibial models were constructed from computed tomography images of legs using the Mimics V.10.01 program and the Geomagic V.10 program. These models were imported to the Catia V.5 program to perform the finite element analysis for determining stress distributions in the tibia. The finite element models showed that the maximum von Mises stress found on the tibia of the female patient was higher than in the male patient since the contact area on the distal end of the female was smaller than in the male. Furthermore, the maximum von Mises stress occurred near the middle of the posterior tibia at 30º knee flexion and was slightly shifted toward the medial tibia during 30–90º knee flexion. As body weight increased, the maximum von Mises stress also increased. Moreover, the maximum von Mises stresses obtained from the smaller contact area were 17.6–25.2% (for a female patient) and 14.5–19.9% (for a male patient) higher than those determined from a larger contact area.