Simulation of Osteoporotic Bone Remodeling - Computational Biomechanics of the Musculoskeletal System - page 331

25 Simulation of Osteoporotic

Bone Remodeling

He Gong, Yubo Fan, and Ming Zhang

ContentS
Summary ........................................................................................................................................ 331
25.1 Introduction ......................................................................................................................... 332
25.2 Development of Bone Remodeling Process Simulation Models for Osteoporosis ............ 332
25.2.1 Model Development .............................................................................................. 332
25.2.1.1 Computational Simulation of Trabecular Bone Remodeling ............... 332
25.2.1.2 Computational Simulation of Cortical Bone Remodeling ................... 334
25.2.2 Model Validation ................................................................................................... 336
25.2.2.1 Model Validation for the Computational
Simulation of Trabecular Bone Remodeling ........................................ 336
25.2.2.2 Model Validation for the Computational
Simulation of Cortical Bone Remodeling ............................................ 337
25.3 Results from the Model Analysis ........................................................................................ 338
25.3.1 Results for Trabecular Bone Loss Associated with Mechanical Disuse and
Estrogen Deficiency .............................................................................................. 338
25.3.2 Results for Cortical Bone Loss Associated with Mechanical Disuse ................... 339
25.4 Applications of the Model ................................................................................................... 339
Acknowledgments .......................................................................................................................... 341
References ...................................................................................................................................... 341

Summary
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 func-
tional adaptation. There are two fundamental physiological processes of bone functional adapta-
tion: 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 struc-
tural 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 osteopo-
rosis. 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 pro-
cess 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.

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