Computational Analysis of Femoral Strength and Fracture Location of Normal, Osteoarthritis and Avascular Necrosis Femurs using CT-Image based Finite Element Method

Abstract

Recent years, the risk of hip fractures in elderly people has exponentially increased due to a progressive loss of bone mass and bone structure deterioration due to osteoporosis and increased incidental falls. It is, therefore, expected that the prediction of femoral strength and fracture location of specific patient will be clinically very useful. It is also considered that some typical femoral diseases such as osteoarthritis (OA) and avascular necrosis (AVN) could affect the strength and fracture behaviour of the femurs. In this study, 130 computational femoral models were constructed using CT images of 73 patients. Then, CT image based finite element method (CT-FEM) combined with a damage mechanics analysis was applied to predict the fracture load as the femoral strength and the fracture location of the femoral models. The computational results exhibited that the fracture load tended to increase with increase of the volumetric bone mineral density (vBMD) estimated in the femoral head and neck region in all the three types of models, although AVN models showed much wider scatter in the data than the other two types. The bone fracture behaviour was expressed as expressed as the distribution of failure elements in the head and neck region. The bone fracture mainly took place in the neck region for all types of femoral model. In addition, a combination of the head and neck fracture was also observed in all the models. A combination of neck and intertrochanteric fracture was also observed in the normal and AVN groups.