The parameters of density and mechanical strength of bone tissue in diagnosis of osteoporosis

The paper presents results of a study, in which an incomplete correlation between the mineral bone tissue density and patient susceptibility to bone fractures was confirmed. A simple model describing distribution of internal forces present in the microstructure of trabecular bone is proposed. The purpose of this model is to demonstrate that parameters of mechanical strength depend not only on the quantity of mineral material in the bone, but also on the quality of the trabecular structure. In addition, we present the results of cortical and trabecular bone micro hardness test, which are then used to calculate of the modulus of elasticity. Micro-hardness test was performed using Micro-Combi-Tester equipment. Micro-hardness was measured with Vickers diamond; analysis of displacement prosperities was carried out by Olivier and Pharr method. Young's modulus was calculated directly from the resulting unloading curve. Generally, the results for both cortical and trabecular bone tests correspond to the results known from literature. However, depending on localization of the test, slight deviations in modulus of elasticity occur. In conclusion of this research, it is proposed that the dependence between bone mineral density and Young's modulus can be calculated using samples of a normal bone and a bone with changed biomechanical properties. The aim of this research would be to estimate a quantitative coefficient, which would describe differences between mineral bone density and the bone's real density, which is responsible for the immunity to fractures.