Side-artifact errors in yield strength and elastic modulus for human trabecular bone and their dependence on bone volume fraction and anatomic site

JOURNAL OF BIOMECHANICS

卷:40

Article

BeVill, Grant ; Easley, Sarah K. ; Keaveny, Tony M.

关键词: cancellous bone;    finite element modeling;    bone quality;    bone biomechanics;    bone strength;   

DOI  :  10.1016/j.jbiomech.2007.05.008

来源: Elsevier

【 摘 要 】

In the context of reconciling the mechanical properties of trabecular bone measured from in vitro mechanical testing with the true in situ behavior, recent attention has focused on the side-artifact which results from interruption of the trabecular network along the sides of machined specimens. The objective of this study was to compare the magnitude of the side-artifact error for measurements of elastic modulus vs. yield stress and to determine the dependence of these errors on anatomic site and trabecular micro-architecture. Using a series of parametric variations on micro-CT-based finite element models of trabecular bone from the human vertebral body (n = 24) and femoral neck (it = 10), side-artifact correction factors were quantified as the ratio of the side-artifact-free apparent mechanical property to the corresponding property measured in a typical experiment. The mean (SD) correction factors for yield stress were 1.32 +/- 0.17 vs. 1.20 +/- 0.11 for the vertebral body and femoral neck (p < 0.05), respectively, and the corresponding factors for modulus were 1.24 +/- 0.09 vs. 1.10 +/- 0.04 (p < 0.0001). Correction factors were greater for yield stress than modulus (p < 0.003), but no anatomic site effect was detected (p > 0.29) after accounting for variations in bone volume fraction (BV/TV). Approximately 30-55% of the variation in the correction factors for modulus and yield stress could be accounted for by BV/TV or micro-architecture, representing an appreciable systematic component of the error. Although some scatter in the correction factor-BV/TV relationships may confound accurate correction of modulus and yield stress for individual specimens, side-artifact correction is nonetheless essential for obtaining accurate mean estimates of modulus and yield stress for a cohort of specimens. We conclude that appreciation and correction for the differential effects of the side-artifact in modulus vs. yield stress and their dependence on BV/TV may improve the interpretation of measured elastic and failure properties for trabecular bone. (c) 2007 Elsevier Ltd. All rights reserved.

【 授权许可】

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