Comparison of Mixed and Kinematic Uniform Boundary Conditions in Homogenized Elasticity of Femoral Trabecular Bone Using Microfinite Element Analyses

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Jarunan Panyasantisuk ◽  
Dieter H. Pahr ◽  
Thomas Gross ◽  
Philippe K. Zysset
Keyword(s):  
Boundary Conditions ◽  
Trabecular Bone ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Volume Fraction ◽  
Bone Fragility ◽  
Model Parameters ◽  
Bone Volume Fraction ◽  
Age Related ◽  
Future Work

Mechanical properties of human trabecular bone play an important role in age-related bone fragility and implant stability. Microfinite element (μFE) analysis allows computing the apparent elastic properties of trabecular bone for use in homogenized FE (hFE) analysis, but the results depend unfortunately on the type of applied boundary conditions (BCs). In this study, 167 human femoral trabecular cubic regions with a side length of 5.3 mm were extracted from three proximal femora and analyzed using μFE analysis to compare systematically their stiffness with kinematic uniform BCs (KUBCs) and periodicity-compatible mixed uniform BCs (PMUBCs). The obtained elastic constants were then used in the volume fraction and fabric-based orthotropic Zysset–Curnier model to identify their respective model parameters. As expected, PMUBCs lead to more compliant apparent elastic properties than KUBCs, especially in shear. The differences in stiffness decreased with bone volume fraction and mean intercept length (MIL). Unlike KUBCs, PMUBCs were sensitive to heterogeneity of the biopsies. The Zysset–Curnier model fitted the apparent elastic constants successfully in both cases with adjusted coefficients of determination (radj2) of 0.986 for KUBCs and 0.975 for PMUBCs. The proper use of these BCs for hFE analysis of whole bones will need to be investigated in future work.

Contributions of Trabecular Rods of Various Orientations in Determining the Elastic Properties of Human Vertebral Trabecular Bone

2007 ◽  
Author(s):  
Xiaowei S. Liu ◽  
X. Henry Zhang ◽  
Paul Sajda ◽  
Punam K. Saha ◽  
Felix W. Wehrli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Trabecular Bone ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Micro Computed Tomography ◽  
Bone Volume Fraction ◽  
Human Trabecular Bone ◽  
Vertebral Trabecular Bone ◽  
Age Related

Osteoporosis is an age-related disease characterized by low bone mass and architectural deterioration. Other than bone volume fraction (BV/TV), microarchitecture of trabecular bone, such as trabecular type (rods or plates), connectivity, and orientation of the trabecular network is also believed to be important in governing the mechanical properties of trabecular bone. A recent study [1] showed that the microarchitecture alone affects elastic moduli of trabecular bone and, further, that trabecular plates make a far greater contribution than rods. In human vertebral trabecular bone, the roles of transverse vs. vertical rods in conferring mechanical properties of trabecular bone have been debated [2, 3]. It has been suggested that the role of transverse trabecular rod is critical in determining elastic modulus of vertebral trabecular bone. However, without explicit classifications of trabecular type, or orientation assessment at an individual trabecula level, it is not possible yet to test this hypothesis in human trabecular bone samples despite the development of three-dimensional (3D) micro computed tomography (μCT) and μCT based finite element (FE) models of human trabecular bone. With the newly developed technique of complete volumetric decomposition and individual trabecula based orientation analyses [4], now it is possible to quantitatively examine the contributions of trabecular rods of various orientations in the elastic properties of vertebral trabecular bone.

Impact of Thresholding Techniques on Micro-CT Image Based Computational Models of Trabecular Bone

2000 ◽  
Author(s):  
Mark J. Eichler ◽  
Chi Hyun Kim ◽  
Ralph Müller ◽  
X. Edward Guo
Keyword(s):  
Mechanical Properties ◽  
Trabecular Bone ◽  
Computational Models ◽  
Volume Fraction ◽  
Bone Fractures ◽  
Bone Adaptation ◽  
Bone Architecture ◽  
Micro Ct ◽  
Bone Volume Fraction ◽  
Age Related

Abstract Age-related bone fractures are mostly influenced by trabecular bone sites. Trabecular bone constantly adapts its bone volume fraction (BV/TV) and orientation, and thus its mechanical properties, to mechanical usage. Therefore, understanding the trabecular bone adaptation process and its consequences will contribute to the better understanding of the etiology of age-related fractures. Micro-computed tomography (micro-CT) is a relatively new method to quantify the complex three-dimensional (3D) trabecular bone architecture [1,2]. Finite element computational studies can be performed on these 3D microstructural images by converting each image voxel into an element [3,4,5]. Image thresholding techniques to segment bone voxels from bone marrow voxels have a major impact on the results of these models. However, the influence of different types of thresholding techniques on the mechanical properties of bone has not been examined carefully.

scholarly journals Predicting trabecular bone elastic properties from measures of bone volume fraction and fabric on the basis of micromagnetic resonance images

2011 ◽  
Vol 68 (2) ◽  
pp. 463-473 ◽  
Author(s):  
Michael J. Wald ◽  
Jeremy F. Magland ◽  
Chamith S. Rajapakse ◽  
Yusuf A. Bhagat ◽  
Felix W. Wehrli
Keyword(s):  
Trabecular Bone ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Volume Fraction

scholarly journals Gracility of the modern Homo sapiens skeleton is the result of decreased biomechanical loading

2014 ◽  
Vol 112 (2) ◽  
pp. 372-377 ◽  
Author(s):  
Timothy M. Ryan ◽  
Colin N. Shaw
Keyword(s):  
Physical Activity ◽  
Trabecular Bone ◽  
Proximal Femur ◽  
Volume Fraction ◽  
Bone Structure ◽  
Homo Sapiens ◽  
Trabecular Bone Structure ◽  
Human Populations ◽  
Bone Volume Fraction ◽  
Age Related

The postcranial skeleton of modern Homo sapiens is relatively gracile compared with other hominoids and earlier hominins. This gracility predisposes contemporary humans to osteoporosis and increased fracture risk. Explanations for this gracility include reduced levels of physical activity, the dissipation of load through enlarged joint surfaces, and selection for systemic physiological characteristics that differentiate modern humans from other primates. This study considered the skeletal remains of four behaviorally diverse recent human populations and a large sample of extant primates to assess variation in trabecular bone structure in the human hip joint. Proximal femur trabecular bone structure was quantified from microCT data for 229 individuals from 31 extant primate taxa and 59 individuals from four distinct archaeological human populations representing sedentary agriculturalists and mobile foragers. Analyses of mass-corrected trabecular bone variables reveal that the forager populations had significantly higher bone volume fraction, thicker trabeculae, and consequently lower relative bone surface area compared with the two agriculturalist groups. There were no significant differences between the agriculturalist and forager populations for trabecular spacing, number, or degree of anisotropy. These results reveal a correspondence between human behavior and bone structure in the proximal femur, indicating that more highly mobile human populations have trabecular bone structure similar to what would be expected for wild nonhuman primates of the same body mass. These results strongly emphasize the importance of physical activity and exercise for bone health and the attenuation of age-related bone loss.

scholarly journals Multiple exposures to unloading decrease bone's responsivity but compound skeletal losses in C57BL/6 mice

2012 ◽  
Vol 303 (2) ◽  
pp. R159-R167 ◽  
Author(s):  
Shikha Gupta ◽  
Surabhi Vijayaraghavan ◽  
Gunes Uzer ◽  
Stefan Judex
Keyword(s):  
Trabecular Bone ◽  
Volume Fraction ◽  
Hindlimb Unloading ◽  
Bone Volume Fraction ◽  
Trabecular Thickness ◽  
Multiple Exposures ◽  
Mechanical Unloading ◽  
Age Related ◽  
First Time

A single exposure to mechanical unloading can result in significant bone loss, but the consequences of multiple exposures are largely unknown. Within a 18-wk period, adult C57BL/6 male mice were exposed to 2 wk of hindlimb unloading (HLU) followed by 4 wk of reambulation (RA) once (1x-HLU), twice (2x-HLU), or three times (3x-HLU), or served as ambulatory age-matched controls. In vivo μCT longitudinally tracked changes in trabecular and cortical compartments of the femur. Normally ambulating control mice experienced significant age-related loss in trabecular bone volume fraction throughout the course of the experiment. This loss was compounded by HLU with 2x- and 3x-HLU mice experiencing a 27% and 24% greater reduction in trabecular bone and a 60% and 63% inhibition of age-related trabecular thickening. The recovery of cortical bone was also incomplete during each 4-wk RA period and, at completion of the experiment, cortical area in 3x-HLU mice was 5% smaller than in control and 1x-HLU. When eliminating age as a confounding variable, comparison between individual HLU/RA cycles showed that the magnitude of the response diminished during subsequent exposures. The extent of trabecular thinning in mice unloaded for the first time was 1.6-fold greater than the second time and nearly twofold greater than the third time. Similarly, the increase in trabecular thickness during the first RA cycle was twofold greater than during the second and third RA cycle. Together, our data demonstrate that even though multiple exposures to mechanical unloading are more detrimental than a single unloading period, bone's mechanosensitivity is reduced with consecutive unloading/reambulation cycles.

scholarly journals Bone health in spacefaring rodents and primates: systematic review and meta-analysis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Jingyan Fu ◽  
Matthew Goldsmith ◽  
Sequoia D. Crooks ◽  
Sean F. Condon ◽  
Martin Morris ◽  
...  
Keyword(s):  
Bone Formation ◽  
Trabecular Bone ◽  
Bone Health ◽  
Volume Fraction ◽  
Meta Analysis ◽  
Bone Volume ◽  
Trabecular Bone Volume ◽  
Bone Volume Fraction ◽  
Percentage Difference ◽  
Induced Changes

AbstractAnimals in space exploration studies serve both as a model for human physiology and as a means to understand the physiological effects of microgravity. To quantify the microgravity-induced changes to bone health in animals, we systematically searched Medline, Embase, Web of Science, BIOSIS, and NASA Technical reports. We selected 40 papers focusing on the bone health of 95 rats, 61 mice, and 9 rhesus monkeys from 22 space missions. The percentage difference from ground control in rodents was –24.1% [Confidence interval: −43.4, −4.9] for trabecular bone volume fraction and –5.9% [−8.0, −3.8] for the cortical area. In primates, trabecular bone volume fraction was lower by –25.2% [−35.6, −14.7] in spaceflight animals compared to GC. Bone formation indices in rodent trabecular and cortical bone were significantly lower in microgravity. In contrast, osteoclast numbers were not affected in rats and were variably affected in mice. Thus, microgravity induces bone deficits in rodents and primates likely through the suppression of bone formation.

scholarly journals Biaxial Normal Strength Behavior in the Axial-Transverse Plane for Human Trabecular Bone—Effects of Bone Volume Fraction, Microarchitecture, and Anisotropy

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Arnav Sanyal ◽  
Tony M. Keaveny
Keyword(s):  
Trabecular Bone ◽  
Volume Fraction ◽  
Elastic Anisotropy ◽  
Bone Volume ◽  
Transverse Plane ◽  
Mechanical Anisotropy ◽  
Bone Volume Fraction ◽  
Human Trabecular Bone ◽  
Strength Behavior ◽  
Normal Strength

The biaxial failure behavior of the human trabecular bone, which has potential relevance both for fall and gait loading conditions, is not well understood, particularly for low-density bone, which can display considerable mechanical anisotropy. Addressing this issue, we investigated the biaxial normal strength behavior and the underlying failure mechanisms for human trabecular bone displaying a wide range of bone volume fraction (0.06–0.34) and elastic anisotropy. Micro-computed tomography (CT)-based nonlinear finite element analysis was used to simulate biaxial failure in 15 specimens (5 mm cubes), spanning the complete biaxial normal stress failure space in the axial-transverse plane. The specimens, treated as approximately transversely isotropic, were loaded in the principal material orientation. We found that the biaxial stress yield surface was well characterized by the superposition of two ellipses—one each for yield failure in the longitudinal and transverse loading directions—and the size, shape, and orientation of which depended on bone volume fraction and elastic anisotropy. However, when normalized by the uniaxial tensile and compressive strengths in the longitudinal and transverse directions, all of which depended on bone volume fraction, microarchitecture, and mechanical anisotropy, the resulting normalized biaxial strength behavior was well described by a single pair of (longitudinal and transverse) ellipses, with little interspecimen variation. Taken together, these results indicate that the role of bone volume fraction, microarchitecture, and mechanical anisotropy is mostly accounted for in determining the uniaxial strength behavior and the effect of these parameters on the axial-transverse biaxial normal strength behavior per se is minor.

Architectural changes of trabecular bone caused by the remodeling process

2005 ◽  
Vol 874 ◽  
Author(s):  
Richard Weinkamer ◽  
Markus A. Hartmann ◽  
Yves Brechet ◽  
Peter Fratzl
Keyword(s):  
Trabecular Bone ◽  
Feedback Loop ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Bone Volume ◽  
Bone Architecture ◽  
Mechanical Problem ◽  
Bone Volume Fraction ◽  
Obvious Effect ◽  
Trabecular Bone Architecture

AbstractUsing a stochastic lattice model we have studied the architectural changes of trabecular bone occurring while the structure is remodeled. Our model considers the mechanical feedback loop, which control the remodeling process. A fast algorithm was employed to solve approximately the mechanical problem. A general feature of the model is that a networklike structure emerges, which further coarsens while the bone volume fraction remains unchanged. Decreasing the mechanical response of the system by either lowering the external load or the internal mechano-sensitivity leads not only to a reduction of the bone volume fraction, but results in topological changes of the trabecular bone architecture, where the loss of horizontal trabeculae is the most obvious effect.

scholarly journals Trabecular bone patterning in the hominoid distal femur

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5156 ◽  
Author(s):  
Leoni Georgiou ◽  
Tracy L. Kivell ◽  
Dieter H. Pahr ◽  
Matthew M. Skinner
Keyword(s):  
Trabecular Bone ◽  
Distal Femur ◽  
Volume Fraction ◽  
Reaction Force ◽  
Intraspecific Variability ◽  
Trabecular Structure ◽  
Trabecular Architecture ◽  
Micro Computed Tomography ◽  
Bone Volume Fraction ◽  
Distal Epiphysis

BackgroundIn addition to external bone shape and cortical bone thickness and distribution, the distribution and orientation of internal trabecular bone across individuals and species has yielded important functional information on how bone adapts in response to load. In particular, trabecular bone analysis has played a key role in studies of human and nonhuman primate locomotion and has shown that species with different locomotor repertoires display distinct trabecular architecture in various regions of the skeleton. In this study, we analyse trabecular structure throughout the distal femur of extant hominoids and test for differences due to locomotor loading regime.MethodsMicro-computed tomography scans ofHomo sapiens(n= 11),Pan troglodytes(n= 18),Gorilla gorilla(n= 14) andPongosp. (n= 7) were used to investigate trabecular structure throughout the distal epiphysis of the femur. We predicted that bone volume fraction (BV/TV) in the medial and lateral condyles inHomowould be distally concentrated and more anisotropic due to a habitual extended knee posture at the point of peak ground reaction force during bipedal locomotion, whereas great apes would show more posteriorly concentrated BV/TV and greater isotropy due to a flexed knee posture and more variable hindlimb use during locomotion.ResultsResults indicate some significant differences between taxa, with the most prominent being higher BV/TV in the posterosuperior region of the condyles inPanand higher BV/TV and anisotropy in the posteroinferior region inHomo. Furthermore, trabecular number, spacing and thickness differ significantly, mainly separatingGorillafrom the other apes.DiscussionThe trabecular architecture of the distal femur holds a functional signal linked to habitual behaviour; however, there was more similarity across taxa and greater intraspecific variability than expected. Specifically, there was a large degree of overlap in trabecular structure across the sample, andHomowas not as distinct as predicted. Nonetheless, this study offers a comparative sample of trabecular structure in the hominoid distal femur and can contribute to future studies of locomotion in extinct taxa.

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