DEVELOPMENT OF A FINITE ELEMENT TOOL FOR STRESS ANALYSIS OF A SURGICALLY ALTERED FEMUR

Abstract

This paper reports the development of a tool for analyzing stresses in a surgically altered femur. The three-dimensional FE model incorporates a novel approach to implementing orthotropic and heterogeneous bone properties and non-uniform distributed loading. The model contains cortical, cancellous, and subchondral bone incorporating experimentally determined mechanical properties to characterize the anisotropy and heterogeneity of the bone. Ligaments and muscles of the joint are represented to more fully describe the loading condition. Use of the tool is demonstrated for an anterior cruciate ligament (ACL) reconstruction with button-type fixation and the knee joint at full extension. The stresses at the tunnel aperture on the femoral cortex produced from the fixation were noticeable for low levels of loading. Forces from the ligaments and muscles had only slight influence on the stresses at the aperture. Repeated compression of the femoral cortex at these stress levels may cause microdamage to the cortex eventually resulting in fatigue failure.