TY - JOUR
T1 - Principal stiffness orientation and degree of anisotropy of human osteons based on nanoindentation in three distinct planes
AU - Reisinger, Andreas G.
AU - Pahr, Dieter H.
AU - Zysset, Philippe K.
N1 - Funding Information:
The authors thank the Austrian Science Fund (FWF) for grant support (Grant No. P19009-N20 ) and the Hochschuljubiläumsstiftung of Vienna for sponsoring a part of the used computational resources (Grant No. H-1906/2010 ).
PY - 2011/11
Y1 - 2011/11
N2 - Haversian systems or 'osteons' are cylindrical structures, formed by bone lamellae, that make up the major part of human cortical bone. Despite their discovery centuries ago in 1691 by Clopton Havers, their mechanical properties are still poorly understood.The objective of this study is a detailed identification of the anisotropic elastic properties of the secondary osteon in the lamella plane. Additionally, the principal material orientation with respect to the osteon is assessed. Therefore a new nanoindentation method was developed which allows the measurement of indentation data in three distinct planes on a single osteon.All investigated osteons appeared to be anisotropic with a preferred stiffness alignment along the axial direction with a small average helical winding around the osteon axis. The mean degree of anisotropy was 1.75 ± 0.36 and the mean helix angle was 10.3 °±0.8° These findings oppose two well established views of compact bone microstructure: first, the generally clear axial stiffness orientation contradicts a regular 'twisted plywood' collagen fibril orientation pattern in lamellar bone that would lead to a more isotropic behavior. Second, the class of transverse osteons were not observed from the mechanical point of view.
AB - Haversian systems or 'osteons' are cylindrical structures, formed by bone lamellae, that make up the major part of human cortical bone. Despite their discovery centuries ago in 1691 by Clopton Havers, their mechanical properties are still poorly understood.The objective of this study is a detailed identification of the anisotropic elastic properties of the secondary osteon in the lamella plane. Additionally, the principal material orientation with respect to the osteon is assessed. Therefore a new nanoindentation method was developed which allows the measurement of indentation data in three distinct planes on a single osteon.All investigated osteons appeared to be anisotropic with a preferred stiffness alignment along the axial direction with a small average helical winding around the osteon axis. The mean degree of anisotropy was 1.75 ± 0.36 and the mean helix angle was 10.3 °±0.8° These findings oppose two well established views of compact bone microstructure: first, the generally clear axial stiffness orientation contradicts a regular 'twisted plywood' collagen fibril orientation pattern in lamellar bone that would lead to a more isotropic behavior. Second, the class of transverse osteons were not observed from the mechanical point of view.
KW - Anisotropic elastic properties
KW - Helical winding
KW - Human cortical bone
KW - Multi-axial nanoindentation
KW - Secondary osteon
KW - Stiffness orientation
UR - http://www.scopus.com/inward/record.url?scp=81255127525&partnerID=8YFLogxK
U2 - 10.1016/j.jmbbm.2011.07.010
DO - 10.1016/j.jmbbm.2011.07.010
M3 - Journal article
C2 - 22098911
AN - SCOPUS:81255127525
SN - 1751-6161
VL - 4
SP - 2113
EP - 2127
JO - Journal of the mechanical behavior of biomedical materials
JF - Journal of the mechanical behavior of biomedical materials
IS - 8
ER -