Simulation of trabecular surface remodeling based on local stress nonuniformity

In this study, to investigate mechanical remodeling of cancellous bone from the viewpoint of trabecular surface remodeling due to trabecular level mechanical stimuli, a rate equation for trabecular surface remodeling is proposed based on the uniform stress hypothesis, which suggests that nonuniformity in the local stress distribution on the trabecular surface is the driving force for remodeling. A proposed local rate equation for trabecular surface remodeling is applied to a computational simulation of morphological changes, in which the trabeculae are modeled as an assemblage of two-dimensional boxel elements and their morphological changes are simulated by removal/addition of the elements from/to the trabecular surface. The basic features of the proposed rate equation and simulation method are investigated through remodeling simulations applied to the basic trabecular-level structure, cancellous-bone-level structure and the proximal femur. In all cases, the trabecular orientation, thickness and connectivity are adapted to the mechanical environment, which demonstrates the capability of the proposed rate equation for computational prediction of the adaptation phenomenon and supports the hypothesis regarding the optimality of trabecular architecture as a mechanical load bearing structure.