The Influence of Different Parameters of Remodeling Rule on the Resultant Density Distribution of the Proximal Femur

The process of adaptive bone remodeling can be described mathematically and simulated with a self-optimizing finite element (FE) model. The aim of this study was to find the bone density distribution of the proximal femur which is affected by the muscle loadings and the hip joint contact force. The basic remodeling rule, which is an objective function for an optimization process relative to external load, was applied to predict the bone density. Its purpose is to obtain a constant value for the strain energy per unit bone mass, by adapting density. The precise solution is dependent on the loads, initial conditions and the parameters in the remodeling rule. The forces at different phases of the gait cycle (walking) were applied as boundary conditions. The density distributions from these loadings were averaged to find the density distribution in the proximal femur. Three different initial densities were considered to investigate the effect of initial conditions. The influence of different parameters and functions on the density distribution and its convergence rate was also investigated. The results were comparable with an actual bone density distribution of the femoral neck head and proximal femoral shaft. It was shown that by applying more boundary conditions through the gait cycle, the converged density distribution is smoother, and more comparable with actual proximal femur.