Goulet Grant C, Hamilton Nicolas, Cooper David, Coombe Dennis, Tran David, Martinuzzi Robert, Zernicke Ronald F
Schulich School of Engineering, Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB, Canada.
J Biomech. 2008 Jul 19;41(10):2169-75. doi: 10.1016/j.jbiomech.2008.04.022. Epub 2008 Jun 4.
Load-induced fluid flow is a key factor in triggering bone modeling and remodeling processes that maintain bone mass and architecture. To provide an enhanced understanding of fluid flow in bone, unique computational models of a tibial section were developed. The purpose of the study was to examine the effects of incorporating vascular porosity on pore fluid pressure and resulting lacunocanalicular flow and to determine the role of load-induced fluid flow in tracer transport. Simulations revealed large local pressure gradients surrounding the vascular canals that were dependent on the magnitude and state (i.e., compressive or tensile) of the stress. Fluid velocity magnitudes were increased by over an order of magnitude in the dual-porosity model, relative to the single-porosity model. Fluid flow had a marked effect on tracer perfusion within the cortex. After 10 loading cycles, a 9-fold increase in tracer concentration, relative to diffusion alone, was observed in the compressive region where fluid exchange was greatest between the lacunocanalicular porosity and the vascular canals. Agreement was achieved between computational results and experimental investigations of electrokinetic phenomenon, tracer transport, cellular stimulation, and functional adaptation. The models produced substantial improvements in bone fluid flow simulation and underscored the significance of incorporating vascular porosity in models designed to quantify fluid pressure and flow characteristics within mechanically loaded cortical bone.
负荷诱导的流体流动是触发维持骨量和结构的骨建模与重塑过程的关键因素。为了更深入地了解骨内的流体流动，开发了独特的胫骨截面计算模型。本研究的目的是研究纳入血管孔隙率对孔隙流体压力及由此产生的骨陷窝小管内流动的影响，并确定负荷诱导的流体流动在示踪剂传输中的作用。模拟结果显示，血管周围存在较大的局部压力梯度，其取决于应力的大小和状态（即压缩或拉伸）。相对于单孔隙率模型，双孔隙率模型中的流体速度大小增加了一个数量级以上。流体流动对皮质内的示踪剂灌注有显著影响。在10个加载周期后，在骨陷窝小管孔隙率与血管之间流体交换最大的压缩区域，相对于仅扩散而言，示踪剂浓度增加了9倍。计算结果与电动现象、示踪剂传输、细胞刺激和功能适应的实验研究结果一致。这些模型在骨流体流动模拟方面有显著改进，并强调了在旨在量化机械加载皮质骨内流体压力和流动特性的模型中纳入血管孔隙率的重要性。
