Mechanical analysis and numerical simulation of modified bone cements in the hip joint alloplasty

Purpose: The paper aims at verifying the stress values in bone-cement-implant system during human movement cycle and determining the amount of bone cement admixture which induces a drop in mechanical properties to acceptable level. Design/methodology/approach: In the first place, mechanical tests of modified cements were carried out. These tests are a basis for mathematical description of mechanical properties which will be used during numerical simulations. Numerical simulations were carried out using the geometry obtained by computer tomography. Findings: A drop in mechanical properties induced by modification depends on admixture size. During movement, cement bond is affected by considerable forces. These forces operate cyclically, i.e. momentarily (when setting a foot on the ground) within the elastic range of examined material. From the point of view of mechanical parameters, an optimum admixture of the aqueous solution of biologically active modifying agent is that inducing porosity at a level of 8%. Research limitations/implications: The paper constitutes a beginning of examinations on modified cement junctures which may be expanded in future by testing the dynamics basing on the analysis of fatigue strength. Practical implications: Modifying agent amount was determined and verified that does not induce a decrease in the bending strength and the longitudinal modulus of elasticity during bending below the level specified in ISO 5833 standard. Originality/value: Modification of cement with aqueous solution of salmon calcitionin, as well as examination and verification of the effect of admixture on mechanical properties.