Microstructural heterogeneity and the fracture toughness of bone.

Age-related changes in the skeleton often lead to an increase in the susceptibility of bone to fracture. The purpose of this study was to determine whether differences in material properties between the osteonal and interstitial regions of bone have an effect on bone fracture properties. Parameters such as longitudinal fracture toughness, transverse fracture toughness, porosity, interstitial microhardness, osteonal microhardness, bone density, and weight fractions of the mineral and organic phases of bone were examined as a function of age using female baboon femurs. With increasing age, the longitudinal fracture toughness decreased significantly as did transverse fracture toughness, whereas the interstitial microhardness increased. However, no significant differences in the other parameters were observed as a function of age. Using the ratio of interstitial microhardness to osteonal microhardness as a measure of the differences in the material properties in these two regions, correlation analysis revealed that the longitudinal fracture toughness of bone has a significant correlation with the microhardness ratio. Localized differences in material properties between osteonal and interstitial regions of bone increase with age; such differences may result in high stress concentrations at cement lines and facilitate longitudinal crack propagation.

[1]  David J. Sheskin,et al.  Handbook of Parametric and Nonparametric Statistical Procedures , 1997 .

[2]  G. Holt,et al.  A non-human primate model for the study of osteoporosis and oral bone loss. , 1993, Bone.

[3]  G. Kiebzak.  Age-related bone changes , 1991, Experimental Gerontology.

[4]  W C Hayes,et al.  Compact bone fatigue damage: a microscopic examination. , 1977, Clinical orthopaedics and related research.

[5]  K. Pritzker,et al.  Bone mineral and osteoporosis in aging rhesus monkeys. , 1989, Puerto Rico health sciences journal.

[6]  P Zioupos,et al.  Experimental and theoretical quantification of the development of damage in fatigue tests of bone and antler. , 1996, Journal of biomechanics.

[7]  W C Hayes,et al.  Fracture mechanics parameters for compact bone--effects of density and specimen thickness. , 1977, Journal of biomechanics.

[8]  J. Currey,et al.  The effects of drying and re-wetting on some mechanical properties of cortical bone. , 1988, Journal of biomechanics.

[9]  R. Colman,et al.  Skeletal effects of aging in male rhesus monkeys. , 1999, Bone.

[10]  D B Burr,et al.  Composition of the cement line and its possible mechanical role as a local interface in human compact bone. , 1988, Journal of biomechanics.

[11]  Y. Yeni,et al.  Influence of bone composition and apparent density on fracture toughness of the human femur and tibia. , 1998, Bone.

[12]  J A McGeough,et al.  Age-related changes in the tensile properties of cortical bone. The relative importance of changes in porosity, mineralization, and microstructure. , 1993, The Journal of bone and joint surgery. American volume.

[13]  S A Goldstein,et al.  A comparison of the fatigue behavior of human trabecular and cortical bone tissue. , 1992, Journal of biomechanics.

[14]  J. Currey,et al.  Microhardness and Young's modulus in cortical bone exhibiting a wide range of mineral volume fractions, and in a bone analogue , 1990 .

[15]  W. Bonfield,et al.  Orientation dependence of the fracture mechanics of cortical bone. , 1989, Journal of biomechanics.

[16]  E. Simmons,et al.  Age‐related changes in the human femoral cortex , 1991, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[17]  K. Gould,et al.  Effects of age and sex on bone density in the rhesus monkey. , 1989, Bone.

[18]  C. M. Agrawal,et al.  Use of a compact sandwich specimen to evaluate fracture toughness and interfacial bonding of bone. , 1994, Journal of applied biomaterials : an official journal of the Society for Biomaterials.

[19]  C Milgrom,et al.  Aging and matrix microdamage accumulation in human compact bone. , 1995, Bone.

[20]  W. Bonfield,et al.  Fracture mechanics of bone--the effects of density, specimen thickness and crack velocity on longitudinal fracture. , 1984, Journal of biomechanics.

[21]  T. M. Boyce,et al.  Aging changes in osteon mineralization in the human femoral neck. , 1994, Bone.

[22]  Y. Yeni,et al.  The influence of bone morphology on fracture toughness of the human femur and tibia. , 1997, Bone.

[23]  W C Hayes,et al.  Fatigue life of compact bone--II. Effects of microstructure and density. , 1976, Journal of biomechanics.

[24]  C. Kammerer,et al.  Effects of age, sex, and heredity on measures of bone mass in baboons (Papio hamadryas) , 1995, Journal of medical primatology.

[25]  W C Hayes,et al.  Age-related differences in post-yield damage in human cortical bone. Experiment and model. , 1996, Journal of biomechanics.

[26]  S A Goldstein,et al.  Micromechanics of osteonal cortical bone fracture. , 1998, Journal of biomechanical engineering.