Effects of the microcrack shape, size and direction on the poroelastic behaviors of a single osteon: a finite element study.

PURPOSE In this work, a finite element study is proposed by using the Comsol Multiphysics software to evaluate the effects of microcrack shape, size and direction on the poroelastic behaviors of a single osteon. METHODS This finite element model is established by using the Comsol Multiphysics software, and we just focus on the comparison of the influences of those microcrack geometric parameters on the osteonal fluid pressure and velocity. RESULTS The results show that: (1) microcracks in the osteon wall can induce a release of the fluid pressure, but enlarge the velocity in this region; (2) equal-area microcrack with ellipsoid-like shape produced a larger fluid pressure and velocity fields in the osteon than that of rectangular shape; (3) in the elliptic microcracks, the longer of the length (major semi-axis) induces a smaller fluid pressure and velocity amplitudes, whereas the width (minor axis) has little effect; (4) the direction of the microcracks (major axial direction) has an limited influence area around about 1/15 of the osteon cross-sectional area. CONCLUSIONS This model permits the linking of the external loads and microcracks to the osteonal fluid pressure and velocity, which can be used for other purpose associate microcracks with the mechanotransduction and bone remodeling.