Age-related changes in the tensile properties of cortical bone. The relative importance of changes in porosity, mineralization, and microstructure.

McCalden, Richard W.; McGeough, J. A.; Barker, M. B.; Court-Brown, Charles M.

doi:10.2106/00004623-199308000-00009

Cited by 640 publications

(397 citation statements)

References 24 publications

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“…23 In addition to this mechanism, the age-related increase in the porosity also results from the increase in the magnitude of resorption and failed formation. 5,24,25 Average size of each osteon also decreased whereas the osteon density showed no dependence on age. This indicates that, with aging, bigger osteons are replaced by smaller osteons.…”

Section: Discussionmentioning

confidence: 94%

“…[2][3][4][5][6] In particular, it has been shown that, similar to cross-sectional parameters, [7][8][9][10][11][12][13][14] microstructural parameters exhibit age-related changes and affect the propensity of bone to fracture. 2 These observations suggest that age-related changes in geometrical and microstructural properties may interact with each other and have a combined effect on bone fractures, however, the level of interaction is unknown.…”

Section: Introductionmentioning

confidence: 99%

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Interactions between microstructural and geometrical adaptation in human cortical bone

Ural

Vashishth

2006

J. Orthop. Res.

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With aging and in disease, the changes in bone microstructure and geometry influence the mechanical properties of cortical bone, however, the level of interaction between the two is not known. Here, we investigate the interaction between the changes in microstructural and geometrical properties of the aging male tibia in proximal and distal middiaphysis. The microstructural measurements include variables related to the size and density of osteons and intracortical porosity. The macroscopic geometrical properties include variables related to bone surfaces (periosteal and endosteal) and cross section (area, moment of inertia). Site-specific correlations were found between the microstructural and geometrical properties along the bone length and at different bone surfaces. In contrast to the proximal middiaphysis of male tibia, where no correlation existed, significant (p < 0.05) correlations were found in the distal middiaphysis of tibia. The changes in parameters partially related to bone formation in the cortex, including the osteonal area, showed positive correlations with an increase in the periosteal diameter. Similarly, parameters related to bone resorption and/or failed formation in the cortex, including porosity and pore size, showed significant correlations with cortical thinning. These findings support the concept that, with aging, anabolic and catabolic responses in the human tibia at microstructural and macrostructural levels are spatially related and site specific. ß

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Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Interactions between microstructural and geometrical adaptation in human cortical bone

Ural

Vashishth

2006

J. Orthop. Res.

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“…Although a major reason is the age-related loss in bone-mineral density (bone quantity) (9,10), recent studies show that the structure and properties of bone specifically degrade with age, independent of the bone-mineral density (11), an issue of bone quality. Indeed, a deterioration in the bone toughness has been correlated with aging (12,13), as a result of a variety of nano-and/ or microstructural changes including progressively larger osteonal dimensions and densities (14), increased nonenzymatic cross-link densities (15), and increased microcracking. In human cortical bone, cross-links occur in two forms: (i) enzymatic crosslinks-as immature intrafibrillar (dehydrodihydroxynorleucine and dehydrohydroxylysinonorleucine) and mature interfibrillar (pyridinoline and pyrrole), and (ii) nonenzymatic advanced glycation end products (AGEs), such as pentosidine, that form both intra-and interfibrillar links along the collagen backbone (16).…”

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confidence: 99%

Age-related changes in the plasticity and toughness of human cortical bone at multiple length scales

Zimmermann

Schaible

Bale

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

343

315

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The structure of human cortical bone evolves over multiple length scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at near-millimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural scales typically below a micrometer and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass ( bone quantity ). However, we find that age-related structural changes can significantly degrade the fracture resistance ( bone quality ) over multiple length scales. Using in situ small-angle X-ray scattering and wide-angle X-ray diffraction to characterize submicrometer structural changes and synchrotron X-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micrometer scales, we show how these age-related structural changes at differing size scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased nonenzymatic collagen cross-linking, which suppresses plasticity at nanoscale dimensions, and to an increased osteonal density, which limits the potency of crack-bridging mechanisms at micrometer scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.

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“…Various reports have supported the role of periosteal apposition as a mechanism to preserve bone strength in the context of agerelated trabecular and cortical bone loss [1,3,7,9,12,19,30,31,33,36,37]. However, none of these reports have focused on examining age-related material and geometric changes in the trochanter and comparing these changes to those observed in the femoral neck.…”

Section: Introductionmentioning

confidence: 99%

Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

Meta

Lü

Keyak

et al. 2006

Bone

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Fragility fractures at the trochanter (TR) and the femoral neck (FN) have distinct etiologies, but the underlying age-related structural changes at these proximal femoral sub-regions are poorly understood. 28 young (41 ± 3 years) and 124 elderly (74 ± 3 years) healthy Caucasian women underwent volumetric quantitative computed tomography at the hip. Integral (i), cortical (c) and trabecular (t) bone mineral density and content (BMD, BMC) were measured. Geometric parameters included cross sectional area (CSA), and volumes of the integral, cortical and trabecular regions (VOL). Structural measures included indices of compressive (Compstr) and bending (BSI) strength. After adjusting for height and weight, an F-test was used to compare the TR and the FN mean values between young and elderly and to test for interaction to compare logarithmic difference of young and elderly (log(Young)-log(Elderly), Y/E d ) between the FN and the TR in an ANOCOVA model. All BMC, iBMD and tBMD values were significantly lower in elderly than in young women, with the largest Y/E d in the FN tBMC and tBMD (P < 0.0011 and P < 0.0001). cBMD in young and elderly groups was not significantly different at the TR while at the FN it was greater (P = 0.0075) in elderly than young women, showing significant Y/E d (P = 0.0003) dependence on skeletal site. Elderly women had significantly larger iVOL and CSA values (0.0001 < P < 0.0051), except for the FN iVOL. cVOL values were smaller in elderly than young women (P < 0.0001). Y/E d in bone geometry differed by sub-region only for cVOL measures (P = 0.0267). Despite larger CSA and iVOL measures in elderly, the younger women had greater Compstr (P < 0.0001) and BSI (P = 0.0051). Thus, although both the TR and the FN appear to increase in size with age, this enlargement is insufficient to protect against loss of bone strength.

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Age-related changes in the tensile properties of cortical bone. The relative importance of changes in porosity, mineralization, and microstructure.

Cited by 640 publications

References 24 publications

Interactions between microstructural and geometrical adaptation in human cortical bone

Interactions between microstructural and geometrical adaptation in human cortical bone

Age-related changes in the plasticity and toughness of human cortical bone at multiple length scales

Young-elderly differences in bone density, geometry and strength indices depend on proximal femur sub-region: A cross sectional study in Caucasian-American women

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