A CANALICULAR FLUID FLOWMODEL ASSOCIATED WITH ITS FLUID FLOWRATE AND FLUID SHEAR STRESS

Stressed bone can be deformed to lead to an interstitial fluid flow or diffusion in its microstructure-osteon (wall). Actually in this fluid diffusion process, some physical effects related with fluid stimuli are induced, such as fluid shear stress (FSS) and streaming potential. These effects may enable the bone cells to detect and respond to the process of bone-resorbing and bone-forming to adapt the external loading environment. Due to the limitation of experimental approach, theoretical simulation has become the main method to study the bone's interstitial fluid flowing behavior. Based on the poroelasticity, a physical canaliculi model is developed to link the mechanical loading on osteon scale to the scale of canalicular fluid flow, which makes a significant step to study the mechanism of the bone mechanotransduction and electromechanotransduction. This developed canaliculi model is based on a hollow osteon model and a Haversian fluid considered osteon model, with two boundary cases on the outer wall, elastic restrained and rigid confined. Finally, the analytical solutions for canalicular fluid flow rates (FFR) and shear stress are obtained. The results predict that the amplitudes of fluid flow rate and shear stress are proportional to strain amplitude and frequency. However, the key loading factor governing canalicular fluid flow behavior is the strain rate, which is a representative loading parameter under a physiological state. The larger canalicular radius is, the larger amplitudes of FFR and FSS generalized, especially, the FSS amplitude is proportional to canalicular radius. The Haversian fluid can enhance the whole canalicular fluid flow rates and shear stress fields.