Design Of Osteosynthesis Plates With Reduced Stress Shielding Effect Using Topology Optimization

Abstract

The article presents analysis of stress shielding effect (SSE) in osteosynthesis plates, its adverse effects on healing of bone fractures and possible solutions for its minimization. It is shown that SSE can be reduced by using plates made of materials with low elastic modulus (β titanium alloys, bioresorbable polymers etc.) or by optimization of their geometric shape. The latter possibility is analysed in a more detailed way with special accent on topology optimization (TO) as a relatively new optimization tool widely used by biomedical engineering community. As a practical example, TO using Comsol Multiphysics software is applied to solution of 2D design problem of osteosynthesis plate. It is shown that longitudinal stiffness of optimized plate can be reduced up to 84 % relative to initial non-optimized design depending on the value of prescribed reduction of weight used as constraint during analysis. Optimized design demonstrates increase in maximum von Mises stress, but overall distribution of stresses becomes more uniform in comparison with initial design. Prototype of optimized plate can be easily manufactured using laser cutting or wire electric discharge machining.