AN ENERGY DISSIPATION-BASED MODEL FOR DAMAGE STIMULATED BONE ADAPTATION

Based on experimental observations, several researchers have proposed a role for damage processes in stimulating an adaptive response in bon e. In the current study we propose a model for bone adaptation based o n cyclic energy dissipation as a measure of bone damage creation. By r eanalyzing the fatigue data of Pattin et al. (1996), we derive a uniax ial form of the damage based formulation applicable to cortical region s experiencing primarily longitudinal stresses. Because of the experim entally observed difference between damage formation under tension and compression (Pattin et al., 1996), this formulation naturally predict s a difference in the adaptive response to tensile and compressive loa ding. This feature distinguishes the new formulation from existing str ain energy based adaptation theories which treat tensile and compressi ve strains identically. Thus, developmental adaptation in response to unequal generation of damage provides one possible explanation for the experimentally observed difference between peak tensile and compressi ve bone surface strains. (C) 1998 Elsevier Science Ltd. All rights res erved.