Comparison of theoretical models for the study of load-induced fluid displacements in bone

A fatigue microcrack alters fluid velocities in a computational model of interstitial fluid flow in cortical bone

“…Several models have been created to estimate fluid flow in bone (Kufahl and Saha, 1990;Cowin et al, 1995;Keanini et al, 1995;Steck et al, 1998;Wang et al, 1999;Steck et al, 2000;Tami et al, 2002;Kaliyamoorthy and Knothe Tate, 2004). Unfortunately, only a few studies report values of fluid flow velocity magnitude, although a greater number report shear stress values.…”

“…Within cortical bone, a mechanical load causes pressure gradients to occur in the fluid and these pressure gradients cause fluid flow (Steck et al, 1998). The maximum axial strain that the second metatarsal experiences during gait corresponds to a 1.1 N m bending moment about the medial-lateral (x) axis, a 0.3 N m bending moment about the plantar-dorsal (y) axis, and a 450 N compressive axial load along the long axis of the bone (Donahue, 1999).…”

“…This is beneficial because the size scale of such models is comparable to the size scale of a whole bone. Since mechanical loading of bone creates the pressure gradients that drive fluid through the porous spaces of bone tissue, this is a desirable modeling approach (Knothe Steck et al, 1998).…”

Top down and bottom up engineering of bone

“…To then account for spatiotemporal transport of solutes in the bone fluid, we predict flow through the micro and nanochannels of bone using the Navier Stokes equations, assuming that inertial effects can be ignored. We then apply the diffusion convection equation for transport to predict the concentration of solutes in space and time (Steck et al, 1998(Steck et al, , 2003bSteck, 2001). (Gatzka et al, 1999; designed to provide controlled loading histories to a particular bone, we then can obtain experimental measures of transport and validate the computational model predictions.…”