Structural and behavioural analysis of children's cortical bones (original) (raw)

Mechanical properties of children cortical bone: A bimodal characterization

For cortical bone, important changes of the elastic properties values have been clearly shown in ageing but not in childhood, furthermore recent works considered osteoporosis as a pediatric disease with geriatric consequences and children are concerned by specific infantile osteo-pathologies. That is why there is a strong interest in the characterisation of the growing process of children bone. However, few mechanical properties of cortical growing bone are available in literature and do not yield to gold standards. Results found in litterature for children bone concern specific location (close to cancerous cells) or cadaveric bone. They indicate a lower Young's modulus for children bone compare to mature bone. The goal of this study is to provide elastic properties values for human growing cortical bone. To reach this goal, we have analysed surgery waste (bone transplantation) from long bone (fibula). In a first step, a non destructive method was used to evaluate the velocity o...

Children cortical bone characterisation: the ultrasonic issue

217 For cortical bone, important changes of the elastic properties values have been clearly shown in ageing but not in childhood, furthermore recent works considered osteoporosis as a pediatric disease with geriatric consequences and children are concerned by specific infantile osteo-pathologies. That is why there is a strong interest in the characterisation of the growing process of children bone. However, few mechanical properties of cortical growing bone are available in literature and do not yield to gold standards. Results found in litterature for children bone concern specific location (close to cancerous cells) or cadaveric bone. They indicate a lower Young's modulus for children bone compare to mature bone. The goal of this study is to provide elastic properties values for human growing cortical bone. To reach this goal, we have analysed surgery waste (bone transplantation) from long bone (fibula). In a first step, a non destructive method was used to evaluate the veloci...

Anisotropy of Child Cortical Fibula Bone for Seven Different Children Ages and Adult Tibia Bone

International Journal of Scientific Research in Chemistry, 2019

The norm of elastic constant tensor and the norms of the irreducible parts of the elastic constants of the child cortical fibula bone for seven different children ages and adult tibia bone are calculated. The relation of the scalar parts norms and the other parts norms and the anisotropy of these bones is presented. The norm ratios are used as a criterion to present the anisotropy degree of the properties of these.

Anisotropy of Young's modulus of human tibial cortical bone

Medical & Biological Engineering & Computing, 2000

The anisotropy of Young's modulus in human cortical bone was determined for all spatial directions by performing coordinate rotations of a 6 by 6 elastic stiffness matrix. The elastic stiffness coefficients were determined experimentally from ultrasonic velocity measurements on 96 samples of normal cortical bone removed from the right tibia of eight human cadavers. The following measured values were used for our analysis: cll = 19.5 GPa, c22 = 20.1 GPa, c33 = 30.9 GPa, c44 = 5.72 GPa, c55 = 5.17 GPa, c66 = 4.05 GPa, c23 = 12.5 GPa. The remaining coefficients were determined by assuming that the specimens possessed at least an orthorhombic elastic symmetry, and further assuming that c13 --c23 c12 --cll -2c66. Our analysis revealed a substantial anisotropy in Young's modulus in the plane containing the long axis of the tibia, with maxima of 20.9 GPa parallel to the long axis, and minima of 11.8 GPa perpendicular to this axis. A less pronounced anisotropy was observed in the plane perpendicular to the long axis of the tibia. To display our results for the full three-dimensional anisotropy of cortical bone, a closed surface was used to represent Young's modulus in all spatial directions.

Estimation of the elastic modulus of child cortical bone specimens via microindentation

Connective Tissue Research

Purpose: Non-pathological child cortical bone (NPCCB) studies can provide clinicians with vital information and insights. However, assessing the anisotropic elastic properties of NPCCB remains a challenge for the biomechanical engineering community. For the first time, this paper provides elastic moduli values for NPCCB specimens in two perpendicular directions (longitudinal and transverse) and for two different structural components of bone tissue (osteon and interstitial lamellae). Materials and Methods: Microindentation is one of the reference methods used to measure bone stiffness. Here, 8 adult femurs (mean age 82±8.9 years), 3 child femurs (mean age 13.3±2.1 years) and 16 child fibulae (mean age 10.2±3.9 years) were used to assess the elastic moduli of adult and children bones by microindentation. Results: For adult specimens, the mean moduli measured in this study are 18.1 (2.6) GPa for osteons, 21.3 (2.3) GPa for interstitial lamellae and 13.8 (1.7) GPa in the transverse direction. For child femur specimens, the mean modulus is 14.1 (0.8) GPa for osteons, lower than that for interstitial lamellae: 15.5 (1.5) GPa. The mean modulus is 11.8 (0.7) GPa in the transverse direction. Child fibula specimens show a higher elastic modulus for interstitial lamellae 15.8 (1.5) than for osteons 13.5 (1.6), with 10.2 (1) GPa in the transverse direction. Conclusion: For the first time, NPCCB elastic modulus values are provided in longitudinal and transverse directions at the microscale level.

Children Bone Elastic Properties Characterization: An Ultrasonic Issue?

2010

Bone is a composed structure including cortical bone, trabecular bone and bone marrow, but organization of these composites changes during ageing ; indeed, differences can be shown from childhood to old age. But these changes in childhood are not clearly shown. For example, certain studies compare bone density (Bone Mineral Density : BMD) of children, like in Chron disease, but not the stiffness, strength or elastic modulus. Some have chosen specific bone, close to cancellers cells or cadaver fragments. The aim of this study was to determine the elastic properties of the children bone. We have used surgery waste (bone transplantation) from long bone (fibula : essentially composed of cortical bone) of children without metabolic or mineralization disturbances. A specific ultrasound frame able to process very small sample (36 mm high, 11 mm tall, and 0.2 mm thickness) was used to evaluate velocity grading along bone axis. They are moved with 0.1 mm accuracy in x and y axis. For Z axis, azimuth got 0.01˚of accuracy (Fig 1). Nominal frequency can increase from 3 to 10 MHz. Our first results (two samples) show longitudinal (vL) and transversal (vT) velocity of propagation (values in m.s-1) We used the same method as used for isotropic transverse bovine bone frame. In the case of orthotropic we can right 12 elements of rigidity matrix. Comparisons were made between juvenile specimens and mature specimens, and the first result is that the wave velocities, and the associated elastic modulus, are then lower in children than adult around 30 percent less for 11 years old child.

Assessment of elastic coefficients of child cortical bone using resonant ultrasound spectroscopy

Journal of the mechanical behavior of biomedical materials, 2018

The assessment of the anisotropic elastic properties of non-pathological child cortical bone remains a challenge for the biomechanical engineering community and an important clinical issue. Resonant ultrasound spectroscopy (RUS) can be used to determine bone stiffness coefficients from the mechanical resonances of bone specimens. Here, a RUS protocol was used on 7 fibula specimens from children (mean age 14 ± 3 years) to estimate the whole elastic stiffness tensor of non-pathological child cortical bone considered as orthotropic. Despite a small number of sample, results are consistent with this hypothesis, even if a trend towards transverse isotropy is discussed. Indeed, the average values of the 9 independent stiffness coefficients obtained in this study for child bone are: C = 16.73 ± 0.19 GPa, C = 16.19 ± 0.12 GPa, C = 24.47 ± 0.30 GPa, C = 4.14 ± 0.08 GPa, C = 4.16 ± 0.07 GPa, C = 3.13 ± 0.05 GPa, C = 10.14 ± 0.20 GPa, C = 10.67 ± 0.27 GPa, C = 10.25 ± 0.14 GPa.

ELASTIC PROPERTIES OF CORTICAL BONE IN FEMALE HUMAN FEMURS

The evaluation of the physiological and pathophysiological changes in the status of human bones is incomplete without information on the elastic properties of the bone material. To assess the merits of a corresponding noninvasive technique for cortical bone the mechanical parameters of macerated human female femur shafts are evaluated by way of measuring the resonance frequencies and associated mode shapes for the bending, axial and torsional motions. The shafts are considered to behave as hollow cylinders of variable cross section and the bone material is assumed to be isotropic and linearly elastic. It is characterized by its density, Young's modulus and shear modulus. The density and the geometry of the cross sections are determined by digital tomography. Young's modulus and the shear modulus are considered constant along the shaft and calculated on the basis of classical theories by matching iterative mathematical predictions with experimental data. Flexural, longitudinal and torsional motions are measured by means of a stabilized Michelson interferometer. Up to 16 eigenfrequencies in the range of 1 and 20 kHz are examined. Results for the age range of 24-85 years show that Young's modulus of cortical bone decreases with age by approximately 10% whereas the compacta density diminishes by ca. 8%. In view of the uncertainty involved in determining Young's modulus of compact bone and the relative change it exhibits with age the efforts of developing a noninvasive technique for its quantification may not be warranted.

Compositional and mechanical properties of growing cortical bone tissue: a study of the human fibula

Scientific Reports

Human cortical bone contains two types of tissue: osteonal and interstitial tissue. Growing bone is not well-known in terms of its intrinsic material properties. To date, distinctions between the mechanical properties of osteonal and interstitial regions have not been investigated in juvenile bone and compared to adult bone in a combined dataset. In this work, cortical bone samples obtained from fibulae of 13 juveniles patients (4 to 18 years old) during corrective surgery and from 17 adult donors (50 to 95 years old) were analyzed. Microindentation was used to assess the mechanical properties of the extracellular matrix, quantitative microradiography was used to measure the degree of bone mineralization (DMB), and Fourier transform infrared microspectroscopy was used to evaluate the physicochemical modifications of bone composition (organic versus mineral matrix). Juvenile and adult osteonal and interstitial regions were analyzed for DMB, crystallinity, mineral to organic matrix ra...