Prediction of Bone Remodeling in Rat Caudal Vertebrae Based on Fluid-Solid Coupling Simulation

Some previous researches have demonstrated that appropriate mechanical stimulation can enhance bone formation. However, most studies have employed the strain energy density (SED) method for predicting bone remodeling, with only a few considering the potential impact of wall fluid shear stress (FSS) on this process. To bridge this gap, the current study compared the prediction of bone formation and resorption via SED and wall FSS by using fluid-solid coupling numerical simulation. Specifically, 8-week-old female Sprague–Dawley rats were subjected to stretching of the eighth caudal vertebra using a custom-made device. Based on micro-computed tomography images, a three-dimensional model integrating fluid–solid coupling was created to represent compact bone, cancellous bone, and bone marrow. The animals were grouped into control, 1 Hz, and 10 Hz categories, wherein a tensile displacement load of 1000 με was applied to the loading end. The results revealed that SED values tended to increase with elevated porosity, whereas wall FSS values decreased it. Notably, wall FSS demonstrated the higher predictive accuracy for cancellous bone resorption than SED. These findings support the notion that fluid flow within cancellous bone spaces can significantly impact bone resorption. Therefore, the findings of this study contribute to a more comprehensive understanding of the role of wall FSS in bone remodeling, providing a theoretical support for the dynamic evolution of bone structures under mechanical stimulation.