TY - JOUR
T1 - Numerical modeling of long bone adaptation due to mechanical loading
T2 - Correlation with experiments
AU - Chennimalai Kumar, Natarajan
AU - Dantzig, Jonathan A.
AU - Jasiuk, Iwona M.
AU - Robling, Alex G.
AU - Turner, Charles H.
N1 - Funding Information:
We would like to thank Prof. Daniel Tortorelli of Department of Mechanical Science and Engineering, UIUC, for his help and advice on the smoothing filter approach, and Khanh Nguyen of Biomedical Engineering, Purdue, for the strain gage measurements. The support of the University of Illinois and the NIH through Grant AR046530 is also gratefully acknowledged.
PY - 2010/3
Y1 - 2010/3
N2 - The process of external bone adaptation in cortical bone is modeled mathematically using finite element (FE) stress analysis coupled with an evolution model, in which adaptation response is triggered by mechanical stimulus represented by strain energy density. The model is applied to experiments in which a rat ulna is subjected to cyclic loading, and the results demonstrate the ability of the model to predict the bone adaptation response. The FE mesh is generated from micro-computed tomography (μCT) images of the rat ulna, and the stress analysis is carried out using boundary and loading conditions on the rat ulna obtained from the experiments [Robling, A. G., F. M. Hinant, D. B. Burr, and C. H. Turner. J. Bone Miner. Res. 17:1545-1554, 2002]. The external adaptation process is implemented in the model by moving the surface nodes of the FE mesh based on an evolution law characterized by two parameters: one that captures the rate of the adaptation process (referred to as gain); and the other characterizing the threshold value of the mechanical stimulus required for adaptation (referred to as threshold-sensitivity). A parametric study is carried out to evaluate the effect of these two parameters on the adaptation response. We show, following comparison of results from the simulations to the experimental observations of Robling et al. (J. Bone Miner. Res. 17:1545-1554, 2002), that splitting the loading cycles into different number of bouts affects the threshold-sensitivity but not the rate of adaptation. We also show that the threshold-sensitivity parameter can quantify the mechanosensitivity of the osteocytes.
AB - The process of external bone adaptation in cortical bone is modeled mathematically using finite element (FE) stress analysis coupled with an evolution model, in which adaptation response is triggered by mechanical stimulus represented by strain energy density. The model is applied to experiments in which a rat ulna is subjected to cyclic loading, and the results demonstrate the ability of the model to predict the bone adaptation response. The FE mesh is generated from micro-computed tomography (μCT) images of the rat ulna, and the stress analysis is carried out using boundary and loading conditions on the rat ulna obtained from the experiments [Robling, A. G., F. M. Hinant, D. B. Burr, and C. H. Turner. J. Bone Miner. Res. 17:1545-1554, 2002]. The external adaptation process is implemented in the model by moving the surface nodes of the FE mesh based on an evolution law characterized by two parameters: one that captures the rate of the adaptation process (referred to as gain); and the other characterizing the threshold value of the mechanical stimulus required for adaptation (referred to as threshold-sensitivity). A parametric study is carried out to evaluate the effect of these two parameters on the adaptation response. We show, following comparison of results from the simulations to the experimental observations of Robling et al. (J. Bone Miner. Res. 17:1545-1554, 2002), that splitting the loading cycles into different number of bouts affects the threshold-sensitivity but not the rate of adaptation. We also show that the threshold-sensitivity parameter can quantify the mechanosensitivity of the osteocytes.
KW - Cortical bone adaptation
KW - Evolution law
KW - Finite element modeling
KW - Loading bouts
KW - Rat ulna
UR - http://www.scopus.com/inward/record.url?scp=77952010862&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77952010862&partnerID=8YFLogxK
U2 - 10.1007/s10439-009-9861-4
DO - 10.1007/s10439-009-9861-4
M3 - Article
C2 - 20013156
AN - SCOPUS:77952010862
SN - 0090-6964
VL - 38
SP - 594
EP - 604
JO - Annals of Biomedical Engineering
JF - Annals of Biomedical Engineering
IS - 3
ER -