Bone maintenance and remodeling: a control system based on fatigue damage.
This paper explores the relationship between damage, repair, and remodeling in compact bone. A model of microcrack growth is developed that takes account of recent findings on the behaviour of small fatigue cracks in other materials. This is combined with a simple model of a repair process, envisaged as a constant rate of decrease in crack length. The system that results is capable of achieving a stable and precise control of crack length without the need to measure it. This is very useful because it implies that bone does not require the complexities of crack-measuring transducers or active decision-making processes. A simple explanation is suggested for the presence of a "lazy zone" of remodeling equilibrium strains, and the limits of this zone are quantified. The model is developed through a necessarily simplified geometry and loading scheme but can be extended to provide a general solution applicable to in vivo conditions.
Taylor
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Mechanical Engineering Department, Trinity College, Dublin, Ireland. dtaylor@tcd.ie
D016723:Bone Remodeling; D001842:Bone and Bones / Q000293:injuries* / Q000503:physiopathology; D015775:Fractures, Stress / Q000503:physiopathology*; D008954:Models, Biological; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology