@article{Boughton:2018:10.1371/journal.pone.0200475,
author = {Boughton, OR and Ma, S and Zhao, S and Arnold, M and Lewis, A and Hansen, U and Cobb, J and Giuliani, F and Abel, R},
doi = {10.1371/journal.pone.0200475},
journal = {PLoS ONE},
title = {Measuring bone stiffness using spherical indentation},
url = {http://dx.doi.org/10.1371/journal.pone.0200475},
volume = {13},
year = {2018}
}

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TY  - JOUR
AB  - ObjectivesBone material properties are a major determinant of bone health in older age, both in terms of fracture risk and implant fixation, in orthopaedics and dentistry. Bone is an anisotropic and hierarchical material so its measured material properties depend upon the scale of metric used. The scale used should reflect the clinical problem, whether it is fracture risk, a whole bone problem, or implant stability, at the millimetre-scale. Indentation, an engineering technique involving pressing a hard-tipped material into another material with a known force, may be able to assess bone stiffness at the millimetre-scale (the apparent elastic modulus). We aimed to investigate whether spherical-tip indentation could reliably measure the apparent elastic modulus of human cortical bone.Materials and methodsCortical bone samples were retrieved from the femoral necks of nineteen patients undergoing total hip replacement surgery (10 females, 9 males, mean age: 69 years). The samples underwent indentation using a 1.5 mm diameter, ruby, spherical indenter tip, with sixty indentations per patient sample, across six locations on the bone surfaces, with ten repeated indentations at each of the six locations. The samples then underwent mechanical compression testing. The repeatability of indentation measurements of elastic modulus was assessed using the co-efficient of repeatability and the correlation between the bone elastic modulus measured by indentation and compression testing was analysed by least-squares regression.ResultsIn total, 1140 indentations in total were performed. Indentation was found to be repeatable for indentations performed at the same locations on the bone samples with a mean co-efficient of repeatability of 0.4 GigaPascals (GPa), confidence interval (C.I): 0.33–0.42 GPa. There was variation in the indentation modulus results between different locations on the bone samples (mean co-efficient of repeatability: 3.1 GPa, C.I: 2.2–3.90 GPa). No cle
AU  - Boughton,OR
AU  - Ma,S
AU  - Zhao,S
AU  - Arnold,M
AU  - Lewis,A
AU  - Hansen,U
AU  - Cobb,J
AU  - Giuliani,F
AU  - Abel,R
DO  - 10.1371/journal.pone.0200475
PY  - 2018///
SN  - 1932-6203
TI  - Measuring bone stiffness using spherical indentation
T2  - PLoS ONE
UR  - http://dx.doi.org/10.1371/journal.pone.0200475
UR  - http://hdl.handle.net/10044/1/62013
VL  - 13
ER  - 

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