Simulated aging--a novel method for estimating the risk of fracture of trabecular bone.

In the study we show how the methods of percolation theory could be used in the description of age-related changes of mechanical competence of trabecular bone. A previously introduced stochastic model of remodeling of trabecular bone is applied to the simulated aging of pairs of 2D sections of trabecular bone matched for apparent density, structural anisotropy, and the age of the donors. The critical density of the structures--defined here as the density below which percolating bone cluster disappears, i.e., the structure is fractured--is estimated for each structure. It is shown that structures belonging to pairs matched for density (clinically used as the principal determinant of fracture risk) lose mechanical competence at a different rate, depending on the value of critical density. Thus it is hypothesized that the risk of fracture must depend not only on the density of the structure but also on its critical density.