Damage Accumulation in Compact Bone — A Fracture Mechanics Approach to Estimate Damage and Repair Rates

Fatigue crack propagation (F.C.P.) in compact bone has not yet been characterized using a fracture mechanics model. Difficulty arises because the growth of very short cracks (which appear as diffuse microstructural damage) is much more influenced by microstructure than ‘long’ cracks. In particular, the short crack growth rate — short cracks are defined as cracks which are shorter than some crack-arresting microstructural feature — decreases as the crack length increases whereas the inverse is true for long cracks. This paper presents a fracture mechanics model which predicts the growth of both long and short fatigue microdamage. The model is applied to the prediction of remodelling and repair rates in compact bone.