scholarly journals Increased Microstructural Variability is Associated With Decreased Structural Strength But With Increased Measures of Structural Ductility in Human Vertebrae

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Janardhan Yerramshetty ◽  
Do-Gyoon Kim ◽  
Yener N. Yeni
Keyword(s):  
Fracture Risk ◽  
Bone Strength ◽  
Volume Fraction ◽  
Average Density ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Microstructural Parameters ◽  
Vertebral Strength ◽  
Microstructural Variability ◽  
Strength And Ductility

The lack of accuracy in the prediction of vertebral fracture risk from average density measurements, all external factors being equal, may not just be because bone mineral density (BMD) is less than a perfect surrogate for bone strength but also because strength alone may not be sufficient to fully characterize the structural failure of a vertebra. Apart from bone quantity, the regional variation of cancellous architecture would have a role in governing the mechanical properties of vertebrae. In this study, we estimated various microstructural parameters of the vertebral cancellous centrum based on stereological analysis. An earlier study indicated that within-vertebra variability, measured as the coefficient of variation (COV) of bone volume fraction (BV/TV) or as COV of finite element-estimated apparent modulus (EFE) correlated well with vertebral strength. Therefore, as an extension to our earlier study, we investigated (i) whether the relationships of vertebral strength found with COV of BV/TV and COV of EFE could be extended to the COV of other microstructural parameters and microcomputed tomography-estimated BMD and (ii) whether COV of microstructural parameters were associated with structural ductility measures. COV-based measures were more strongly associated with vertebral strength and ductility measures than average microstructural measures. Moreover, our results support a hypothesis that decreased microstructural variability, while associated with increased strength, may result in decreased structural toughness and ductility. The current findings suggest that variability-based measures could provide an improvement, as a supplement to clinical BMD, in screening for fracture risk through an improved prediction of bone strength and ductility. Further understanding of the biological mechanisms underlying microstructural variability may help develop new treatment strategies for improved structural ductility.

scholarly journals Increased Microstructural Variability Is Associated With Decreased Structural Strength but With Increased Measures of Structural Ductility in Human Vertebrae

2009 ◽  
Author(s):  
Janardhan Yerramshetty ◽  
Do-Gyoon Kim ◽  
Yener N. Yeni
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Volume Fraction ◽  
Structural Parameters ◽  
Average Density ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Microstructural Parameters ◽  
Apparent Modulus ◽  
Vertebral Strength

The lack of accuracy in the prediction of vertebral fracture risk from average density measurements, all external factors being equal, may be because bone mineral density (BMD) is less than a perfect surrogate for bone strength but also because strength alone may not be sufficient to fully characterize the structural failure of a vertebra. Apart from bone quantity, organization of micro-architecture would have a role in governing mechanical properties of vertebrae. An earlier study indicated that within-vertebra variability, measured as the coefficient of variation (COV) of bone volume fraction (BV/TV) or as COV of finite element-estimated apparent modulus (EFE) correlated well with vertebral strength [1]. Therefore, as an extension to our earlier study, we investigated i) whether the relationships of vertebral strength found with COV of BV/TV and COV of EFE could be extended to the COV of other micro-structural parameters and microcomputed tomography-estimated bone mineral density (μCT-BMD) and ii) whether COV of microstructural parameters were associated with structural ductility measures.

scholarly journals Skeletal Microstructure and Estimated Bone Strength Improve Following Parathyroidectomy in Primary Hyperparathyroidism

2017 ◽  
Vol 103 (1) ◽  
pp. 196-205 ◽  
Author(s):  
Natalie E Cusano ◽  
Mishaela R Rubin ◽  
Barbara C Silva ◽  
Yu-Kwang Donovan Tay ◽  
John M Williams ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Density ◽  
Primary Hyperparathyroidism ◽  
Fracture Risk ◽  
Bone Strength ◽  
Failure Load ◽  
Mineral Density ◽  
Element Analysis ◽  
Volumetric Bone Density

Abstract Context High-resolution peripheral quantitative computed tomography (HRpQCT) is a noninvasive imaging technology that can provide insight into skeletal microstructure and strength. In asymptomatic primary hyperparathyroidism (PHPT), HRpQCT imaging has demonstrated both decreased cortical and trabecular indices, consistent with evidence for increased fracture risk. There are limited data regarding changes in HRpQCT parameters postparathyroidectomy. Objective To evaluate changes in skeletal microstructure by HRpQCT in subjects with PHPT after parathyroidectomy. Design We studied 29 subjects with PHPT (21 women, 8 men) with HRpQCT at baseline and 6, 12, 18, and 24 months postparathyroidectomy. Main Outcome Measures Volumetric bone mineral density, microarchitectural indices, and finite element analysis at the distal radius and tibia. Results At both the radius and tibia, there were significant improvements in total, cortical, and trabecular volumetric bone density as early as 6 months postparathyroidectomy (24-month values for total volumetric bone density, radius: +2.8 ± 4%, tibia: +4.4 ± 4%; P < 0.0001 for both), cortical thickness (radius: +1.1 ± 2%, tibia: +2.0 ± 3%; P < 0.01 for both), and trabecular bone volume (radius: +3.8 ± 5%, tibia: +3.2 ± 4%; P < 0.0001 for both). At both sites, by finite element analysis, stiffness and failure load were improved starting at 6 months postparathyroidectomy (24-month values for failure load, radius: +6.2 ± 6%, tibia: +4.8 ± 7%; P < 0.0001 for both). Conclusions These results provide information about skeletal microarchitecture in subjects with PHPT followed through 2 years after parathyroidectomy. Estimated bone strength is improved, consistent with data showing decreased fracture risk postparathyroidectomy.

scholarly journals Structure-Function Relationships of the Vertebral Endplate

2021 ◽  
Author(s):  
Yuanqiao Wu ◽  
Elise Feng-i Morgan ◽  
Johnfredy Loaiza ◽  
Rohin Banerji ◽  
Olivia Rose Blouin
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Yield Stress ◽  
Volume Fraction ◽  
Level Density ◽  
Micro Computed Tomography ◽  
Vertebral Endplate ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Apparent Stiffness

Background: Although deformation and fracture of the vertebral endplate have been implicated in spinal conditions such as vertebral fracture and disc degeneration, few biomechanical studies of this structure are available. The goal of this study was to quantify the mechanical behavior of the vertebral endplate. Methods: Eight-five rectangular specimens were dissected from the superior and/or inferior central endplates of human lumbar spine segments L1-L4. Micro-computed tomography (μCT) imaging, four-point-bend testing, and ashing were performed to quantify the apparent elastic modulus and yield stress (modulus and yield stress, respectively, of the porous vertebral endplate), tissue yield stress (yield stress of the tissue of the vertebral endplate, excluding pores), ultimate strain, fracture strain, bone volume fraction (BV/TV), bone mineral density (BMD), and various measures of tissue density and composition (tissue mineral density, ash fraction, and ash density). Regression was used to assess the dependence of mechanical properties on density and composition. Results: Wide variations in elastic and failure properties, and in density and tissue composition, were observed. BMD and BV/TV were good predictors of many of the apparent-level mechanical properties, including modulus, yield stress, and in the case of the inferior vertebral endplate, failure strains. Similar values of the mechanical properties were noted between superior and inferior vertebral endplates. In contrast to the dependence of apparent stiffness and strength on BMD and BV/TV, none of the mechanical properties depended on any of the tissue-level density measurements. Conclusion: The dependence of many of the mechanical properties of the vertebral endplate on BV/TV and BMD suggests possibilities for non-invasive assessment of how this region of the spine behaves during habitual and injurious loading. Further study of the non-mineral components of the endplate tissue is required to understand how the composition of this tissue may influence the overall mechanical behavior of the vertebral endplate.

scholarly journals Teriparatide and Abaloparatide Have a Similar Effect on Bone in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Mikkel Bo Brent ◽  
Frederik Eriksen Stoltenborg ◽  
Annemarie Brüel ◽  
Jesper Skovhus Thomsen
Keyword(s):  
Bone Mineral Density ◽  
Bone Strength ◽  
Bone Mineral ◽  
Volume Fraction ◽  
Bone Cells ◽  
Areal Bone Mineral Density ◽  
Mineral Density ◽  
Bone Formation Rate ◽  
Parathyroid Hormone Related Protein ◽  
Diaphyseal Bone

Three bone anabolic pharmaceuticals are currently approved for treatment of osteoporosis, teriparatide (PTH (1–34)), the parathyroid hormone-related protein analog abaloparatide (ABL), and romosozumab. The present study compared the effect of intermittent PTH (1–34) and ABL on bone tissue directly mole-to-mole in female mice. Forty-seven C57BL/6 mice were randomly allocated to the following groups: Baseline (n = 11), Control (Ctrl) (n = 12), PTH (n = 12), and ABL (n = 12). The mice were injected s.c. with PTH (100 µg/kg), ABL (96 µg/kg), or saline (Ctrl) five days a week for three weeks. To assess the effect of PTH and ABL, the hindlimb bones were analyzed with DXA, µCT, mechanical testing, dynamic bone histomorphometry, and histological quantification of bone cells. In addition, serum calcium concentration was determined. PTH and ABL significantly increased femoral areal bone mineral density (aBMD) (borderline significant p = 0.06 for PTH), femoral mid-diaphyseal bone strength, femoral metaphyseal and epiphyseal and vertebral bone volume fraction (BV/TV), connectivity density, volumetric bone mineral density (vBMD), and bone formation rate (BFR/BS) compared to Ctrl. In addition, ABL also significantly increased mid-diaphyseal cortical thickness and bone area compared to Ctrl. Neither PTH nor ABL significantly increased bone strength at the femoral neck. In conclusion, abaloparatide and PTH have similar bone anabolic properties when compared directly mole-to-mole in mice.

scholarly journals Structural strength of cancellous specimens from bovine femur under cyclic compression

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1562 ◽  
Author(s):  
Kaori Endo ◽  
Satoshi Yamada ◽  
Masahiro Todoh ◽  
Masahiko Takahata ◽  
Norimasa Iwasaki ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Yield Stress ◽  
Bone Strength ◽  
Cancellous Bone ◽  
Structural Model ◽  
Volume Fraction ◽  
Bone Structure ◽  
Micro Computed Tomography ◽  
Bone Volume Fraction ◽  
Structural Deterioration

The incidence of osteoporotic fractures was estimated as nine million worldwide in 2000, with particular occurrence at the proximity of joints rich in cancellous bone. Although most of these fractures spontaneously heal, some fractures progressively collapse during the early post-fracture period. Prediction of bone fragility during progressive collapse following initial fracture is clinically important. However, the mechanism of collapse, especially the gradual loss of the height in the cancellous bone region, is not clearly proved. The strength of cancellous bone after yield stress is difficult to predict since structural and mechanical strength cannot be determineda priori. The purpose of this study was to identify whether the baseline structure and volume of cancellous bone contributed to the change in cancellous bone strength under cyclic loading. A total of fifteen cubic cancellous bone specimens were obtained from two 2-year-old bovines and divided into three groups by collection regions: femoral head, neck, and proximal metaphysis. Structural indices of each 5-mm cubic specimen were determined using micro-computed tomography. Specimens were then subjected to five cycles of uniaxial compressive loading at 0.05 mm/min with initial 20 N loading, 0.3 mm displacement, and then unloading to 0.2 mm with 0.1 mm displacement for five successive cycles. Elastic modulus and yield stress of cancellous bone decreased exponentially during five loading cycles. The decrease ratio of yield stress from baseline to fifth cycle was strongly correlated with bone volume fraction (BV/TV,r= 0.96,p< 0.01) and structural model index (SMI,r= − 0.81,p< 0.01). The decrease ratio of elastic modulus from baseline to fifth cycle was also correlated with BV/TV (r= 0.80,p< 0.01) and SMI (r= − 0.78,p< 0.01). These data indicate that structural deterioration of cancellous bone is associated with bone strength after yield stress. This study suggests that baseline cancellous bone structure estimated from adjacent non-fractured bone contributes to the cancellous bone strength during collapse.

scholarly journals Antiosteoporosis Effect ofRadix ScutellariaeExtract on Density and Microstructure of Long Bones in Tail-Suspended Sprague-Dawley Rats

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Chen-Rui Li ◽  
Guang-Wei Zhang ◽  
Yin-Bo Niu ◽  
Ya-Lei Pan ◽  
Yuan-Kun Zhai ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Volume Fraction ◽  
Bone Microarchitecture ◽  
Osteoclast Differentiation ◽  
Hindlimb Unloading ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Trabecular Thickness ◽  
Radix Scutellariae

Radix Scutellariae (RS), a medicinal herb, is extensively employed in traditional Chinese medicines and modern herbal prescriptions. Two major flavonoids in RS were known to induce osteoblastic differentiation and inhibit osteoclast differentiation, respectively. This study aimed to investigate the effect ofRadix Scutellariaeextract (RSE) against bone loss induced by mechanical inactivity or weightlessness. A hindlimb unloading tail-suspended rat model (TS) was established to determine the effect of RSE on bone mineral density and bone microarchitecture. Treatment of RSE at 50 mg/kg/day and alendronate (ALE) at 2 mg/kg/day as positive control for 42 days significantly increased the bone mineral density and mechanical strength compared with TS group. Enhanced bone turnover markers by TS treatment were attenuated by RSE and ALE administration. Deterioration of bone trabecula induced by TS was prevented. Moreover, both treatments counteracted the reduction of bone volume fraction, trabecular thickness and number, and connectivity density. In conclusion, RSE was demonstrated for the first time to prevent osteoporosis induced by TS treatment, which suggests the potential application of RSE in the treatment of disuse-induced osteoporosis.

scholarly journals Bone quality: what is it and how is it measured?

2006 ◽  
Vol 50 (4) ◽  
pp. 579-585 ◽  
Author(s):  
Juliet Compston
Keyword(s):  
Bone Mineral Density ◽  
Bone Turnover ◽  
Fracture Risk ◽  
Bone Strength ◽  
Bone Quality ◽  
Bone Mineral ◽  
Bone Matrix ◽  
Mineral Density ◽  
New Techniques ◽  
Composition And Structure

Bone quality describes aspects of bone composition and structure that contribute to bone strength independently of bone mineral density. These include bone turnover, microarchitecture, mineralisation, microdamage and the composition of bone matrix and mineral. New techniques to assess these components of bone quality are being developed and should produce important insights into determinants of fracture risk in untreated and treated disease.

2016 The Year That Was: Bone Strength

2017 ◽  
Vol 29 (1) ◽  
pp. 23-25
Author(s):  
Kathleen F. Janz
Keyword(s):  
Physical Activity ◽  
Bone Mineral Density ◽  
Fracture Risk ◽  
Precision Medicine ◽  
Bone Strength ◽  
Bone Development ◽  
High Impact ◽  
Environment Interaction ◽  
Mineral Density ◽  
Field Of Inquiry

Of all the lifestyle strategies for increasing bone strength during the growing years, physical activity is one of the most efficacious. This commentary highlights two exceptional 2016 publications addressing bone strength in children and adolescents with an eye toward reduced fracture risk later in life. The first by Weaver et al. was selected due to its comprehensive approach to understanding bone development. The second by Mitchell et al explores a new field of inquiry, that is, genetic-environment interaction as represented by bone mineral density-lowering alleles and high-impact physical activity. It is a first look at future precision medicine as it may pertain to pediatric bone strength.

Effects of Active Vitamin D or FGF23 Antibody on Hyp Mice Dentoalveolar Tissues

2021 ◽  
pp. 002203452110110
Author(s):  
E.J. Lira dos Santos ◽  
M.B. Chavez ◽  
M.H. Tan ◽  
F.F. Mohamed ◽  
T.N. Kolli ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Volume Fraction ◽  
Fibroblast Growth Factor 23 ◽  
Neutralizing Antibody ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Treatment Regimens ◽  
New Therapeutic Approaches ◽  
Phex Gene

Mutations in the PHEX gene lead to X-linked hypophosphatemia (XLH), a form of inherited rickets featuring elevated fibroblast growth factor 23 (FGF23), reduced 1,25-dihydroxyvitamin D (1,25D), and hypophosphatemia. Hyp mutant mice replicate the XLH phenotype, including dentin, alveolar bone, and cementum defects. We aimed to compare effects of 1,25D versus FGF23-neutralizing antibody (FGF23Ab) monotherapies on Hyp mouse dentoalveolar mineralization. Male Hyp mice, either injected subcutaneously with daily 1,25D or thrice weekly with FGF23 blocking antibody from 2 to 35 d postnatal, were compared to wild-type (WT) controls and untreated Hyp mice. Mandibles were analyzed by high-resolution micro–computed tomography (micro-CT), histology, and immunohistochemistry. Both interventions maintained normocalcemia, increased serum phosphate levels, and improved dentoalveolar mineralization in treated versus untreated Hyp mice. 1,25D increased crown dentin volume and thickness and root dentin/cementum volume, whereas FGF23Ab effects were limited to crown dentin volume. 1,25D increased bone volume fraction, bone mineral density, and tissue mineral density in Hyp mice, whereas FGF23Ab failed to significantly affect these alveolar bone parameters. Neither treatment fully attenuated dentin and bone defects to WT levels, and pulp volumes remained elevated regardless of treatment. Both treatments reduced predentin thickness and improved periodontal ligament organization, while 1,25D promoted a more profound improvement in acellular cementum thickness. Altered cell densities and lacunocanalicular properties of alveolar and mandibular bone osteocytes and cementocytes in Hyp mice were partially corrected by either treatment. Neither treatment normalized the altered distributions of bone sialoprotein and osteopontin in Hyp mouse alveolar bone. Moderate improvements from both 1,25D and FGF23Ab treatment regimens support further studies and collection of oral health data from subjects receiving a newly approved anti-FGF23 therapy. The inability of either treatment to fully correct Hyp mouse dentin and bone prompts further experiments into underlying pathological mechanisms to identify new therapeutic approaches.

scholarly journals The Incorporation of Platelet-rich Plasma into Calcium Phosphate Cement Enhances Bone Regeneration in Osteoporosis

2014 ◽  
Vol 6;17 (6;12) ◽  
pp. E737-E745
Author(s):  
Kyung-Hoon Kim
Keyword(s):  
Bone Regeneration ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Platelet Rich Plasma ◽  
Bone Volume ◽  
Filler Materials ◽  
Trabecular Bone Volume ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Trabecular Thickness

Background: Polymethyl methacrylate (PMMA) bone cement is widely used for osteoplasty. However, previous studies have demonstrated the adverse effects of PMMA due to its excessive stiffness and heat production. Recently, calcium phosphate cement (CPC) that overcomes those negative effects has been successfully applied in osteoplasty. The potential problem of CPC is markedly less initial stiffness. It leads to progressive, repeated collapse in the treated vertebra before CPC has been replaced by new bone that would provide substantial improvement in compressive strength and stiffness. The activated platelets in platelet-rich plasma (PRP) release a high concentration of growth factors which play an important role in bone healing. Objective: To investigate whether PRP could accelerate the osteoconduction of CPC and enhance the bone strength of the treated vertebra in an animal model. Study Design: Controlled animal study. Setting: Laboratory animal study, Methods: Thirty-two female Sprague-Dawley rats were ovariectomized at 8 weeks of age. After 3 months, they were randomly divided into 4 groups and received cement augmentation in the fifth caudal spine with different filler materials; sham-operated rats (S), PMMA (P), CPC (C), and CPC + PRP (CP). Bone mineral density (BMD) and trabecular type-associated morphological parameters, including trabecular bone volume fraction and trabecular thickness in the augmented caudal spine, were evaluated by micro-computed tomography (mirco-CT) 2 weeks after the cementoplasty. Histological analysis was also performed to compare the bone regeneration. Results: The trabecular bone volume fraction in the CP group was significantly greater than those of all the other groups. Trabecular thickness was higher in the CP group than the S and P groups. This augmented trabecular structure in the CP group accordingly showed higher BMD. Histological evaluations showed significantly more bone regeneration in the CP group. Limitations: There has been a concern that the effect of PRP would be dependent on the species, and might show different results in humans. Baseline values of micro-CT analysis were not measured, which could have provided exact evidence of the changes in trabecular microarchitecture parameters and cement resorption profiles. Finally, caudal vertebrae with filler materials used in biological study should have been compared by their mechanical properties using biomechanical evaluations for a more coherent study, which was not possible due to technical problems. Conclusions: Incorporating PRP into CPC could accelerate osteoconduction in the augmented vertebra leading to improvement of trabecular bone microarchitecture and BMD in rats. Key words: Bone mineral density, calcium phosphates, cementoplasty, histology, osteoconduction, osteoporosis, platelet-rich plasma, polymethyl methacrylate, vertebra

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