Numerical evaluation of sensitivity of stress distribution in bone to geometric parameters of endoprosthesis

One of serious drawbacks in the bone endoprosthetics is the implant separation from bone or cement. Stress concentrations on the implant surface are deemed major factor in this process and implant shape optimization seems to be a natural way of improvement of stress distribution. An important tool in effective optimization algorithms is the design sensitivity analysis (DSA).

The discretized formulation of the problem in terms of the finite element method is presented in this paper. A three-dimensional model of femur with a cementless implant is analysed. Frictionless contact and perfect bonding are assumed on the smooth and rough parts of the implant surface, respectively. Computational examples show the stress concentrations and their sensitivity to various geometric parameters of the implant.