Influence of cortical canal architecture on lacunocanalicular pore pressure and fluid flow

Abstract

Bone is a dynamic tissue that undergoes structural modification in response to its mechanical environment, but how bone cells sense and respond to loading conditions remains incompletely understood. Current theories focus on strain-induced fluid flow for the primary means of mechanotransduction. To examine the influence of age-related cortical rarefaction on lacunocanalicular fluid characteristics, coupled fluid flow and mechanical computational models of bone specimens representing young, mid-age and aged samples were derived artificially from the same original micro-computed tomography image data. Simulated mechanical loading was applied to the bone models to induce pressure-driven interstitial fluid flow. Results demonstrated a decrease in pore pressure and fluid velocity magnitudes with age as a result of increased cortical porosity. Mean canal separation, as opposed to canal size, was implicated as a primary factor affecting age-related fluid dynamics. Future investigations through refinement of the model may implicate fluid stasis or inadequate nutrient transport experienced by osteocytes as a key factor in the initiation of cortical remodelling events.

Keywords:

• mechanotransduction
• bone mechanics
• finite element
• fluid dynamics

Acknowledgements

The authors extend thanks to Jasmine Beye for her insightful feedback, the Wood Professorship in Joint Injury Research, the Natural Sciences and Engineering Research Council of Canada, the Alberta Provincial CIHR Training Program in Bone and Joint Health, and the Alberta Heritage Foundation for Medical Research for their funding support.