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Ann Biomed Eng. 2019 Jun;47(6):1391-1399. doi: 10.1007/s10439-019-02238-9. Epub 2019 Mar 12.

Optimizing Accuracy of Proximal Femur Elastic Modulus Equations.

Author information

1
Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street, S.W., Rochester, MN, 55905, USA.
2
Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA.
3
Division of Engineering, Mayo Clinic, Rochester, MN, USA.
4
Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street, S.W., Rochester, MN, 55905, USA. dragomirdaescu.dan@mayo.edu.

Abstract

Quantitative computed tomography-based finite element analysis (QCT/FEA) is a promising tool to predict femoral properties. One of the modeling parameters required as input for QCT/FEA is the elastic modulus, which varies with the location-dependent bone mineral density (ash density). The aim of this study was to develop optimized equations for the femoral elastic modulus. An inverse QCT/FEA method was employed, using an optimization process to minimize the error between the predicted femoral stiffness values and experimental values. We determined optimal coefficients of an elastic modulus equation that was a function of ash density only, and also optimal coefficients for several other equations that included along with ash density combinations of the variables sex and age. All of the optimized models were found to be more accurate than models from the literature. It was found that the addition of the variables sex and age to ash density made very minor improvements in stiffness predictions compared to the model with ash density alone. Even though the addition of age did not remarkably improve the statistical metrics, the effect of age was reflected in the elastic modulus equations as a decline of about 9% over a 60-year interval.

KEYWORDS:

Femoral stiffness; Inverse finite element analysis; Mechanical testing; Optimization; Sex differences

PMID:
30887275
PMCID:
PMC6506372
[Available on 2020-06-01]
DOI:
10.1007/s10439-019-02238-9
[Indexed for MEDLINE]

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