Abstract
Dual X-ray absorptiometry (DXA) measures areal bone mineral density (aBMD) by simplifying a complex 3D bone structure to a 2D projection and is not equally effective for explaining fracture strength in women and men. Unlike DXA, subject-specific quantitative computed tomography-based finite element analysis (QCT/FEA) estimates fracture strength using 3D bone mineral distribution and geometry. By using experimentally-measured femoral stiffness and strength from a one hundred sample cadaveric cohort that included variations in sex and age, we wanted to determine if QCT/FEA estimates were able to better predict the experimental variations than DXA/aBMD. For each femur, DXA/aBMD was assessed and a QCT/FEA model was developed to estimate femoral stiffness and strength. Then, the femur was mechanically tested to fracture in a sideways fall on the hip position to measure stiffness and strength. DXA/aBMD and QCT/FEA estimates were compared for their sensitivity to sex and age with multivariate statistical analyses. When comparing the measured data with DXA/aBMD predictions, both age and sex were significant (p ≤ 0.0398) for both femoral stiffness and strength. However, QCT/FEA predictions of stiffness and strength showed sex was insignificant (p ≥ 0.23). Age was still significant (p ≤ 0.0072). These results indicate that QCT/FEA, unlike DXA/aBMD, accounted for bone differences due to sex.
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Acknowledgments
The study was financially supported by the Grainger Foundation: Grainger Innovation Fund. The CT imaging of the femurs was performed through the Opus CT Imaging Resource of Mayo Clinic (NIH construction Grant RR018898). This publication was made possible by CTSA Grant Number UL1 TR000135 from the National Center for Advancing Translational Sciences (NCATS), a component of the National Institutes of Health (NIH).
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The authors declare that they have no conflict of interest.
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Associate Editor Sean S. Kohles oversaw the review of this article.
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Rezaei, A., Giambini, H., Rossman, T. et al. Are DXA/aBMD and QCT/FEA Stiffness and Strength Estimates Sensitive to Sex and Age?. Ann Biomed Eng 45, 2847–2856 (2017). https://doi.org/10.1007/s10439-017-1914-5
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DOI: https://doi.org/10.1007/s10439-017-1914-5