Reorganization of the femoral cortex due to age‐, sex‐, and endoprosthetic‐related effects emphasized by osteonal dimensions and remodeling

Busse, Björn; Hahn, Michael; Schinke, Thorsten; Püschel, Klaus; Duda, Georg N.; Amling, Michael

doi:10.1002/jbm.a.32432

Cited by 43 publications

(35 citation statements)

References 44 publications

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“…Fig. 4 demonstrates the dramatically higher number of osteons in aged bone; in fact, the aged sample has nearly three times the osteonal density, defined as the number of osteons per unit bone area, consistent with reports elsewhere (24). The higher osteon density in aged bone supports the notion that a growing crack will have more cement lines at which microcracks can form, resulting in both smaller crack bridges and a lower crack-growth toughness.…”

Section: Resultssupporting

confidence: 86%

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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Section: Resultssupporting

confidence: 86%

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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“…and similar rate of mineral deposition at the surface~Sahoo et al, 2006!. That is, as portrayed in experimental studies in materials science that the PSD slopes depended on the rate of particle deposition on the surface, slow surface deposition rate of the material would result in smooth and less complex surface morphology~lower roughness, lower FD; Sahoo et al, 2006!. Apart from the size of mineral crystals, which was linked to bone tissue age in several studies of cortical and trabecular bone~Su et al, 2003;Kuhn et al, 2008;Milovanovic et al, 2011!, the degree of matrix mineralization, which can be expressed in the form of Ca/P ratio, has also been regarded as an indicator of bone age~Legros et al., 1987;Grynpas, 1993;Skedros et al, 1993;Huja et al, 2006;Kuhn et al, 2008;Roschger et al, 2008;Busse et al, 2009Busse et al, , 2010aBusse et al, , 2010b Our spectroscopy analysis showed consistent Ca/P ratio between the groups. Therefore, two independent measures of bone tissue age in our study~crystal size and degree of mineralization!…”

Section: Femoral Neck Outer Diametersupporting

confidence: 80%

Atomic Force Microscopy Characterization of the External Cortical Bone Surface in Young and Elderly Women: Potential Nanostructural Traces of Periosteal Bone Apposition During Aging

et al. 2013

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On the basis of the suggestion that bone nanostructure bears “tissue age” information and may reflect surface deposition/modification processes, we performed nanoscale characterization of the external cortical bone surface at the femoral neck in women using atomic force microscopy (AFM). The specific aims were to assess age-related differences in bone nanostructure and explore the existence of nanostructural traces of potential bone apposition at this surface. Our findings revealed that the external cortical surface represents a continuous phase composed of densely packed mineral grains. Although the grains varied in size and shape, there was a domination of small grains indicative of freshly deposited bone (mean grain size: young, 35 nm; old, 37 nm; p > 0.05). Advanced quantitative analysis of surface morphological patterns revealed comparable roughness and complexity of the surface, suggesting a similar rate of mineral particle deposition at the surface in both groups. Calcium/phosphorus ratio, a measure of bone tissue age, was within the same range in both groups. In summary, our AFM analyses showed consistent nanostructural and compositional bone features, suggesting existence of new bone at the periosteal bone surface in both young and elderly women. Considering observed age-related increase in the neck diameter, AFM findings may support the theory of continuous bone apposition at the periosteal surface.

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“…The results demonstrated that the senior group had the higher porosity area and lower osteon area than the young group [4].…”

Section: Resultsmentioning

confidence: 90%

Effect of micromorphology of cortical bone tissue on crack propagation under dynamic loading

Wang

Gao

Abdel-Wahab

et al. 2015

EPJ Web of Conferences

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Abstract. Structural integrity of bone tissue plays an important role in daily activities of humans. However, traumatic incidents such as sports injuries, collisions and falls can cause bone fracture, servere pain and mobility loss. In addition, ageing and degenerative bone diseases such as osteoporosis can increase the risk of fracture [1]. As a composite-like material, a cortical bone tissue is capable of tolerating moderate fracture/cracks without complete failure. The key to this is its heterogeneously distributed microstructural constituents providing both intrinsic and extrinsic toughening mechanisms. At micro-scale level, cortical bone can be considered as a four-phase composite material consisting of osteons, Haversian canals, cement lines and interstitial matrix. These microstructural constituents can directly affect local distributions of stresses and strains, and, hence, crack initiation and propagation. Therefore, understanding the effect of micromorphology of cortical bone on crack initiation and propagation, especially under dynamic loading regimes is of great importance for fracture risk evaluation. In this study, random microstructures of a cortical bone tissue were modelled with finite elements for four groups: healthy (control), young age, osteoporosis and bisphosphonate-treated, based on osteonal morphometric parameters measured from microscopic images for these groups. The developed models were loaded under the same dynamic loading conditions, representing a direct impact incident, resulting in progressive crack propagation. An extended finite-element method (X-FEM) was implemented to realize solution-dependent crack propagation within the microstructured cortical bone tissues. The obtained simulation results demonstrate significant differences due to micromorphology of cortical bone, in terms of crack propagation characteristics for different groups, with the young group showing highest fracture resistance and the senior group the lowest.

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Reorganization of the femoral cortex due to age‐, sex‐, and endoprosthetic‐related effects emphasized by osteonal dimensions and remodeling

Cited by 43 publications

References 44 publications

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

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

Atomic Force Microscopy Characterization of the External Cortical Bone Surface in Young and Elderly Women: Potential Nanostructural Traces of Periosteal Bone Apposition During Aging

Effect of micromorphology of cortical bone tissue on crack propagation under dynamic loading

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