The Longitudinal Young’s Modulus of Cortical Bone in the Midshaft of Human Femur and its Correlation with CT Scanning Data
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This study was concerned with establishing the regional variations in the magnitude of the longitudinal Young’s modulus of the cortical bone in the femoral midshaft and with investigating whether a relationship existed between the Young’s modulus of bone and the CT number. Were such a relationship to exist this would provide a noninvasive method of assessing the quality of bone in the regions of fixation of implants to bone. The data would be of considerable aid to designers of implant stems to withstand the stresses arising at its interface with the bone. Five pairs of fresh frozen human femora were used. Several beam-shaped small specimens were methodically harvested from each pair and were used to measure the longitudinal modulus adopting the three-point bending test, which was carried out with a specially constructed and validated apparatus. CT scans of the bone were obtained, prior to harvesting the specimens, and the CT number was measured at locations corresponding with the specimen sites. The results indicate that in the femoral midshaft the cortical bone has an average Young’s modulus value of 18600 ± 1900 MPa. This agrees well with data obtained by other researchers using different experimental methods. Statistical analyses revealed no regional variations in the value of the longitudinal modulus of the bone. No correlation was found between the bone modulus and the CT number. Thus a noninvasive method for establishing the bone properties still remains a challenge.
KeywordsHuman femur Young’s modulus CT number Computed tomography Cortical bone
This work was supported by a grant from EPSRC (GR/M86583, GR/R09039). Thanks to Mike Pullan and Brian Whitham, technicians at the Bioengineering Division, University of Leeds for manufacturing the apparatus used in this study and for all their other practical help. The work of Lynne Gathercole, CT Unit, Leeds Teaching Hospitals NHS Trust, and Sonia Lettry, who led the first part of this project, is gratefully acknowledged.
- 5.Burstein, AH, Reilly, DT, Martens, M 1976Ageing of bone tissue: mechanical properties.J Bone Joint Surg Am588286Google Scholar
- 7.McElhaney, JH, Fogle, J, Byers, E, et al. 1964Effects of embalming on the mechanical properties of beef bone.J Appl Physiol1912341236Google Scholar
- 14.Schneider, E, Weber, P, Gasser, B 1987Determination of geometrical and mechanical properties of the distal femur using computed tomography.Jonsson, B eds. Biomechanics X.Human Kinetics PublishersChampaign, Ill10811087Google Scholar
- 15.Lettry, S, Seedhom, BB, Berry, E, Cuppone, M, et al. 2002Quality assessment of the cortical bone of the human mandible.Bone..Google Scholar
- 17.Snyder, SM, Schneider, E 1991Estimation of mechanical properties of cortical bone by computed tomography.J Orthop Rest9422431Google Scholar
- 18.McCalden, RW, McGeogh, JA, Barker, MG, Court Brown, CM 1993Age-related changes in the tensile properties of cortical bone—the relative importance in changes in porosity, mineralization, and microstructure.J Bone Joint Surg Am75A11931205Google Scholar
- 20.Hangartner, TN, Gilsanz, V 1996Evaluation of cortical bone by computer tomography.J Bone Min Res1115181525Google Scholar
- 22.Hoffmeister, BK, Smith, SR, Handley, SM, Rho, JY 2000Anisotropy of Young’s modulus of human tibial cortical bone.Med Biol Eng Comput38333338Google Scholar
- 24.Chen, X, Lam, YM 1997Technical note: CT determination of the mineral density of dry bone specimens using the dipotassium phosphate phantom.Am J Phys Anthropol103557560Google Scholar
- 26.Norusis MJ (1993) SPSS for Windows; Release 6.0, Chicago SPSS 1993Google Scholar