Linear viscoelasticity - bone volume fraction relationships of bovine trabecular bone

Manda, Krishnagoud; Xie, Shuqiao; Wallace, Robert; Levrero-Florencio, Francesc; Pankaj, Pankaj

doi:10.1007/s10237-016-0787-0

Cited by 36 publications

(39 citation statements)

References 40 publications

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“…The strain measured in the first 5 seconds of creep test was treated as elastic strain, and was excluded from the calculation of creep strain. As reported previously [6,7,11,26], the primary creep (T1, Figure 4) lasted approximately 2 to 3 minutes, with a high creep rate. The secondary creep (T2, Figure 4) lasted longer, and had a much lower creep rate.…”

Section: Discussionsupporting

confidence: 84%

Effects of bone damage on creep behaviours of human vertebral trabeculae

O’Callaghan

Szarko

Wang

et al. 2018

Bone

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A subgroup of patients suffering with vertebral fractures can develop progressive spinal deformities over time. The mechanism underlying such clinical observation, however, remains unknown. Previous studies suggested that creep deformation of the vertebral trabeculae may play a role. Using the acoustic emission (AE) technique, this study investigated effects of bone damage (modulus reduction) on creep behaviours of vertebral trabecular bone. Thirty-seven human vertebral trabeculae samples were randomly assigned into five groups (A to E). Bones underwent mechanical tests using similar experimental protocols but varied degree of bone damage was induced. Samples first underwent creep test (static compressive stress of 0.4MPa) for 30min, and then were loaded in compression to a specified strain level (0.4%, 1.0%, 1.5%, 2.5%, and 4% for group A to E, respectively) to induce different degrees of bone damage (0.4%, no damage control; 1.0%, yield strain; 1.5%, beyond yield strain, 2.5% and 4%, post-ultimate strains). Samples were creep loaded (0.4MPa) again for 30min. AE techniques were used to monitor bone damage. Bone damage increased significantly from group A to E (P<0.05), with >30% of modulus reduction in group D and E. Before compressive loading, creep deformation was not different among the five groups and AE hits in creep test were rare. After compressive loading, creep deformation was significantly greater in group D and E than those in other groups (P<0.05). The number of AE hits and other AE measurements during creep test were significantly greater in group D and E than in group A, B, and C (P<0.05 for all). Data suggested that with the increase of vertebral trabecular bone damage, substantial creep deformation may occur even when the vertebra was under physiological loads. The boosted creep deformation observed may be attributed to newly created trabecular microfractures. Findings provide a possible explanation as to why some vertebral fracture patients develop progressive spinal deformity over time.

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Section: Discussionsupporting

confidence: 84%

Effects of bone damage on creep behaviours of human vertebral trabeculae

O’Callaghan

Szarko

Wang

et al. 2018

Bone

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“…First, interfragmentary compression was lost prior to placement of triangular constructs judged by the apparent separation of dorsoproximal cortices. Trabecular bone volume would consequently have returned to precompression dimensions because of the tissue's viscoelastic properties, provided that compression had not resulted in irreversible changes . Second, the width of unloaded fracture gaps was not correlated with the type of repair at every measurement site.…”

Section: Discussionmentioning

confidence: 98%

“…For the purpose of this investigation, a 4‐Nm insertion torque was deemed adequate because of the first author's clinical experience and the equivalency of typically generated forces. Although the observed torque loss of distal implants may have been caused by stress relaxation of adjacent bone and may have indicated overtightening, it followed placement of 2 proximal lag screws. This additive effect on proximal interfragmentary compression likely allowed the distal screw to loosen.…”

Section: Discussionmentioning

confidence: 99%

In vitro comparison of linear vs triangular screw configuration to stabilize complete uniarticular parasagittal fractures of the proximal phalanx in horses

et al. 2018

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Objective To assess fracture gap reduction and stability of linear vs triangular 4.5‐mm lag screw repair of experimental, uniarticular, and complete forelimb proximal phalanx (P1) fractures. Study design Experimental. Sample population Fourteen equine cadaver limbs/horses. Methods Simulated fractures were repaired with 2 lag screws under 4‐Nm insertion torque (linear repair). Computed tomography (CT) imaging was performed with the leg unloaded and loaded to forces generated while walking. The fracture repair was revised to include 3 lag screws placed with the same insertion torque (triangular repair) prior to CT. The width of the fracture gap was assessed qualitatively by 2 observers and graded on the basis of gap measurements relative to the average voxel size at dorsal, mid, and palmar P1 sites. Interobserver agreement was assessed with Cohen's κ. The effect of repair type, loading condition, and measurement site on fracture gap grades was evaluated by using Kendall's τ‐b correlation coefficients and paired nonparametric tests. Significance was set at P ≤ .05. Results Agreement between loading and fracture gap widening was fair in triangular (κ = 0.53) and excellent in linear (κ = 0.81) repairs. Loading resulted in fracture gap distraction in linear repairs (Plinear = .008). Triangular repairs reduced fractures better irrespective of loading (Punloaded = .003; Ploaded < .001). The type of repair was not correlated with fracture gap grades at unloaded mid and loaded dorsal P1 sites. Conclusion Repair of uniarticular complete parasagittal fractures with a triangular screw configuration improved in vitro fracture gap reduction and stability. Clinical significance Triangular lag screw repair likely improves biomechanical conditions during postoperative weight bearing.

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“…Elastic and viscoelastic studies on both cortical and trabecular bones generally give Young’s/shear moduli in the GPa range, though the results vary due to different experimental conditions (11–22). The Young’s/shear modulus of trabecular bone is slightly lower than that of the cortical bone and occasionally as low as 10s - 100s MPa (23, 24). The growth plate is more compliant than both cortical and trabecular bone tissues, with the Young’s modulus ranging from 300 kPa to 50 MPa (25–28).…”

Section: Introductionmentioning

confidence: 99%

Mechanical Heterogeneity in the Bone Microenvironment as Characterised by Atomic Force Microscopy

Hobbs

Chen

Mullin

et al. 2020

Preprint

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Bones are structurally heterogeneous organs with diverse functions that undergo mechanical stimuli across multiple length scales. Mechanical characterisation of the bone microenvironment is important for understanding how bones function in health and disease. Here we describe the mechanical architecture of cortical bone, the growth plate, metaphysis and marrow in fresh murine bones, probed using atomic force microscopy in physiological buffer. Both elastic and viscoelastic properties are found to be highly heterogeneous with moduli ranging over 3 to 5 orders of magnitude, both within and across regions. All regions include extremely soft areas, with moduli of a few Pascal and viscosities as low as tens Pa⋅s. Aging impacts the viscoelasticity of the bone marrow strongly but has limited effect on the other regions studied. Our approach provides the opportunity to explore the mechanical properties of complex tissues at the length scale relevant to cellular processes and how these impact on aging and disease.SIGNIFICANCEThe mechanical properties of biological materials at cellular scale are involved in guiding cell fate. However, there is a critical gap in our knowledge of such properties in complex tissues. The physiochemical environment surrounding the cells in in-vitro studies differs significantly from that found in vivo. Existing mechanical characterisation of real tissues are largely limited to properties at larger scales, structurally simple (e.g. epithelial monolayers) or non-intact (e.g. through fixation) tissues. In this paper, we address this critical gap and present the micro-mechanical properties of the relatively intact bone microenvironment. The measured Young’s moduli and viscosity provide a sound guidance in bioengineering designs. The striking heterogeneity at supracellular scale reveals the potential contribution of the mechanical properties in guiding cell behaviour.

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Linear viscoelasticity - bone volume fraction relationships of bovine trabecular bone

Cited by 36 publications

References 40 publications

Effects of bone damage on creep behaviours of human vertebral trabeculae

Effects of bone damage on creep behaviours of human vertebral trabeculae

In vitro comparison of linear vs triangular screw configuration to stabilize complete uniarticular parasagittal fractures of the proximal phalanx in horses

Mechanical Heterogeneity in the Bone Microenvironment as Characterised by Atomic Force Microscopy

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