Multi-Scale Topology Optimization of Femoral Stem Structure Subject to Stress Shielding Reduce

Abstract

Hip replacement femoral implants are made of substantial materials that all have stiffness considerably higher than that of bone, which can cause significant bone resorption secondary to stress shielding and lead to severe complications. The topology optimization design method based on the uniform distribution of material micro-structure density can form a continuous mechanical transmission route, which can better solve the problem of reducing the stress shielding effect. A multi-scale parallel topology optimization method is proposed in this paper and a topological structure of type B femoral stem is derived. Using the traditional topology optimization method (Solid Isotropic Material with Penalization, SIMP), a topological structure of type A femoral stem is also derived. The sensitivity of the two kinds of femoral stems to the change of load direction is compared with the variation amplitude of the structural flexibility of the femoral stem. Furthermore, the finite element method is used to analyze the stress of type A and type B femoral stem under multiple conditions. Simulation and experimental results show that the average stress of type A and type B femoral stem on the femur are (Formula presented.) MPa, (Formula presented.) MPa, (Formula presented.) MPa and (Formula presented.) MPa, (Formula presented.) MPa, (Formula presented.) MPa, respectively. For type B femoral stem, the average error of strain is (Formula presented.) and the average relative error is (Formula presented.) at the test points on the medial side and the mean error of strain is (Formula presented.) and the mean relative error is (Formula presented.) at the test points on the outside.