Computational determination of the critical microcrack size that causes a remodeling response in a trabecula: a feasibility study.
Bone is a living tissue, which undergoes continuous renewal to repair local defects. Two separate processes, adaptation and remodeling, are involved when a defect appears. The defect produces stress concentrations that provoke regional adaptation, and is gradually repaired, first by resorption and then by deposition of new bone. Using a mathematical formulation of the adaptation mechanism in trabeculae of cancellous bone, we hypothesize that in some cases, where a microcrack is small enough relative to the dimensions of the trabecula, the adaptation response of the whole trabecula may be sufficient to regain homeostatic mechanical conditions (with no need for a remodeling process). The simulation results showed that for trabeculae with nominal length of 900 microm and nominal thickness of 80-800 microm, a microcrack with minimal length of 48 microm and minimal depth of 13% of the trabecula's thickness was required to initiate a remodeling process. A longer (100 microm) but shallower (depth of 7% of the trabecula's thickness) crack also triggered remodeling. These computational results support our hypothesis that when a microcrack small enough relative to the dimensions of the trabecula occurs, adaptation of the whole trabecula may be sufficient to regain homeostatic mechanical conditions with no need for a local remodeling process.
Gefen
Amit
A
Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel.
Neulander
Ron
R
D016723:Bone Remodeling / Q000502:physiology*; D001842:Bone and Bones / Q000503:physiopathology*; D003198:Computer Simulation; D005240:Feasibility Studies; D020342:Finite Element Analysis; D017102:Fracture Healing / Q000502:physiology*; D050723:Fractures, Bone / Q000503:physiopathology*; D006801:Humans; D008954:Models, Biological