Simulation of osteoporotic bone remodeling

As a living biological material, bone has an amazing ability to adapt to mechanical load or other biophysical stimuli in terms of bone mass and architecture-an ability that is known as bone functional adaptation. There are two fundamental physiological processes of bone functional adaptation: modeling and remodeling. Remodeling occurs in all in vivo bone tissues as an important bone renewal mechanism. Bone remodeling is performed by groups of osteoclasts and osteoblasts organized into basic multicellular units (BMUs). Osteoporosis is a systematic skeletal disease with a consequent increase in bone fragility and susceptibility to fracture. With osteoporosis, the structural integrity of trabecular bone is impaired and cortical bone becomes more porous and the cortex becomes thinner. Mechanical usage and biological factors are two major determinants of osteoporosis. Computing power has made it possible to quantitatively simulate the bone remodeling process to predict the bone mass and architecture during adaptation to mechanical load and/or biophysical stimuli. In this chapter, the development of a computational simulation of the bone remodeling process at the BMU level in trabecular bone as well as cortical bone will be introduced, and the related osteoporotic processes will be predicted as examples.