Mechanical stimuli of trabecular bone in osteoporosis: A numerical simulation by finite element analysis of microarchitecture.

Mechanical stimuli are one of the factors that influence bone cell activity and therefore the remodeling of bone. These stimuli are dependent on the microarchitecture of the tissue and can be altered by changes in the bone that occur typically with osteoporosis. The objective of this study was to quantify the variation in the mechanical stimuli of trabecular bone due to changes in the microarchitecture. The morphology of 76 cubes of trabecular bone from human tibia were obtained from microcomputed tomography images and estimated possibilities for mechanical stimuli were determined using poro-viscoelastic finite element models based on the three-dimensional images. The distributions of Von Mises stress, octahedral strain, strain energy density, fluid velocity and pore pressure were predicted for the solid and the marrow phases of bone. We predicted that with variations in the morphology of the trabecular bone, such as an increase of 30% porosity, there is a significant decrease in the mechanical stimuli of the tissue when subjected to constant strain. The average stress and strain in the bone phase may reduce 50% and the fluid velocity in the marrow phase 88%. These decreases may intrinsically affect the mechanoregulation of bone regeneration that contributes to the etiology of osteoporosis.