scholarly journals Rib Cortical Bone Fracture Risk as a Function of Age and Rib Strain: Updated Injury Prediction Using Finite Element Human Body Models

2021 ◽  
Vol 9 ◽  
Author(s):  
Karl-Johan Larsson ◽  
Amanda Blennow ◽  
Johan Iraeus ◽  
Bengt Pipkorn ◽  
Nils Lubbe
Keyword(s):  
Finite Element ◽  
Fracture Risk ◽  
Cortical Bone ◽  
Failure Strain ◽  
Risk Function ◽  
Rib Fracture ◽  
Probabilistic Framework ◽  
Age Dependent ◽  
Risk Curve ◽  
Human Body Models

To evaluate vehicle occupant injury risk, finite element human body models (HBMs) can be used in vehicle crash simulations. HBMs can predict tissue loading levels, and the risk for fracture can be estimated based on a tissue-based risk curve. A probabilistic framework utilizing an age-adjusted rib strain-based risk function was proposed in 2012. However, the risk function was based on tests from only twelve human subjects. Further, the age adjustment was based on previous literature postulating a 5.1% decrease in failure strain for femur bone material per decade of aging. The primary aim of this study was to develop a new strain-based rib fracture risk function using material test data spanning a wide range of ages. A second aim was to update the probabilistic framework with the new risk function and compare the probabilistic risk predictions from HBM simulations to both previous HBM probabilistic risk predictions and to approximate real-world rib fracture outcomes. Tensile test data of human rib cortical bone from 58 individuals spanning 17–99 years of ages was used. Survival analysis with accelerated failure time was used to model the failure strain and age-dependent decrease for the tissue-based risk function. Stochastic HBM simulations with varied impact conditions and restraint system settings were performed and probabilistic rib fracture risks were calculated. In the resulting fracture risk function, sex was not a significant covariate—but a stronger age-dependent decrease than previously assumed for human rib cortical bone was evident, corresponding to a 12% decrease in failure strain per decade of aging. The main effect of this difference is a lowered risk prediction for younger individuals than that predicted in previous risk functions. For the stochastic analysis, the previous risk curve overestimated the approximate real-world rib fracture risk for 30-year-old occupants; the new risk function reduces the overestimation. Moreover, the new function can be used as a direct replacement of the previous one within the 2012 probabilistic framework.

Relationships Between Stiffness of Human Distal Tibia, Distal Radius, Proximal Femur, and Vertebral Body Assessed by HR-pQCT and cQCT Based Finite Element Analyses

2009 ◽  
Author(s):  
X. Sherry Liu ◽  
Adi Cohen ◽  
Perry T. Yin ◽  
Joan M. Lappe ◽  
Robert R. Recker ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Mechanical Properties ◽  
Finite Element ◽  
Lumbar Spine ◽  
Fracture Risk ◽  
Cortical Bone ◽  
Bone Strength ◽  
Distal Radius ◽  
Proximal Femur ◽  
Quantitative Computed Tomography

High-resolution peripheral quantitative computed tomography (HR-pQCT) is a promising clinical tool that permits separate measurements of trabecular and cortical bone compartments at the distal radius and tibia. It has an isotropic voxel size of 82 μm, which is high enough to assess the fine microstructural details of trabecular architecture. HR-pQCT images can also be used for building microstructural finite element (μFE) models to estimate the mechanical competence of whole bone segments. Melton et al. showed that derived bone strength parameters (axial rigidity and fall load to failure load ratio) are additional to BMD and bone geometry and microstructure as determinants of forearm fracture risk prediction [1]. Boutroy et al. found that the proportion of the load carried by trabecular bone versus cortical bone is associated with wrist fracture independently of BMD and microarchitecture [2]. These clinical studies demonstrate that HR-pQCT based μFE analyses can provide measurements of mechanical properties that independently associate with fracture risk. However, microstructure of one skeletal site may be different from that of another site. It is unclear whether and to what extent these peripheral measurements reflect the bone strength of the proximal femur and vertebral bodies, the sites of frequent osteoporotic fractures. Currently, central quantitative computed tomography (cQCT) is the most commonly used clinical imaging modality to quantify the structural and mechanical properties of the proximal femur and lumbar spine. We therefore evaluated relationships between the stiffness of the distal radius and tibia estimated by HR-pQCT-based FEA with that of the proximal femur and lumbar spine which was estimated from cQCT-based FEA in the same human subjects.

scholarly journals MDCT-Based Finite Element Analyses: Are Measurements at the Lumbar Spine Associated with the Biomechanical Strength of Functional Spinal Units of Incidental Osteoporotic Fractures along the Thoracolumbar Spine?

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 455
Author(s):  
Nico Sollmann ◽  
Nithin Manohar Rayudu ◽  
Long Yu Yeung ◽  
Anjany Sekuboyina ◽  
Egon Burian ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Fracture Risk ◽  
Thoracolumbar Spine ◽  
Areal Bone Mineral Density ◽  
Mineral Density ◽  
Osteoporotic Vertebral Fractures ◽  
The Mean ◽  
Biomechanical Strength

Assessment of osteoporosis-associated fracture risk during clinical routine is based on the evaluation of clinical risk factors and T-scores, as derived from measurements of areal bone mineral density (aBMD). However, these parameters are limited in their ability to identify patients at high fracture risk. Finite element models (FEMs) have shown to improve bone strength prediction beyond aBMD. This study aims to investigate whether FEM measurements at the lumbar spine can predict the biomechanical strength of functional spinal units (FSUs) with incidental osteoporotic vertebral fractures (VFs) along the thoracolumbar spine. Multi-detector computed tomography (MDCT) data of 11 patients (5 females and 6 males, median age: 67 years) who underwent MDCT twice (median interval between baseline and follow-up MDCT: 18 months) and sustained an incidental osteoporotic VF between baseline and follow-up scanning were used. Based on baseline MDCT data, two FSUs consisting of vertebral bodies and intervertebral discs (IVDs) were modeled: one standardly capturing L1-IVD–L2-IVD–L3 (FSU_L1–L3) and one modeling the incidentally fractured vertebral body at the center of the FSU (FSU_F). Furthermore, volumetric BMD (vBMD) derived from MDCT, FEM-based displacement, and FEM-based load of the single vertebrae L1 to L3 were determined. Statistically significant correlations (adjusted for a BMD ratio of fracture/L1–L3 segments) were revealed between the FSU_F and mean load of L1 to L3 (r = 0.814, p = 0.004) and the mean vBMD of L1 to L3 (r = 0.745, p = 0.013), whereas there was no statistically significant association between the FSU_F and FSU_L1–L3 or between FSU_F and the mean displacement of L1 to L3 (p > 0.05). In conclusion, FEM measurements of single vertebrae at the lumbar spine may be able to predict the biomechanical strength of incidentally fractured vertebral segments along the thoracolumbar spine, while FSUs seem to predict only segment-specific fracture risk.

scholarly journals Age-Dependent Factors Affecting Thoracic Response: A Finite Element Study Focused on Japanese Elderly Occupants

2015 ◽  
Vol 16 (sup1) ◽  
pp. S66-S74 ◽  
Author(s):  
Jacobo Antona-Makoshi ◽  
Yoshihiro Yamamoto ◽  
Ryosuke Kato ◽  
Fusako Sato ◽  
Susumu Ejima ◽  
...  
Keyword(s):  
Finite Element ◽  
Factors Affecting ◽  
Finite Element Study ◽  
Age Dependent ◽  
Japanese Elderly ◽  
Element Study

Failure Strain and Fracture Prediction During Shock Tube Impact Forming of AA 5052-H32 Sheet

2021 ◽  
pp. 1-39
Author(s):  
Saibal Kanchan Barik ◽  
Ganesh R Narayanan ◽  
Niranjan Sahoo
Keyword(s):  
Finite Element ◽  
Flow Stress ◽  
Shock Tube ◽  
Failure Strain ◽  
Experimental Situation ◽  
Rate Sensitivity ◽  
Fracture Pattern ◽  
Failure Model ◽  
Stress Models ◽  
Cook Model

Abstract The present study deals with both numerical and experimental evaluation of failure strain and fracture pattern during shock tube impact forming of 1.5 mm thick AA 5052-H32 sheet. A hemispherical end nylon striker is propelled to deform the sheet at different velocities. Here the main objective is to understand the effect of flow stress models and fracture models on the forming outputs. The experimental situation is modelled in two stages, i.e., incorporating the pressure in the first stage, and displacement of the striker in the second stage in finite element simulation using the finite element (FE) code (DEFORM-3D). A new strategy followed to evaluate the rate-dependent flow stress data from the tensile test of samples sectioned from shock tube-based deformed sheet is acceptable, and finite element simulations incorporating those properties predicted accurate failure strain and fracture pattern. Out of all the flow stress models, the modified Johnson-Cook model has a better flow stress predictability due to the inclusion of the non-linear strain rate sensitivity term in the model. During the prediction of the failure strain and necking location, Cockcroft-Latham failure model, Brozzo failure model, and Freudenthal failure model have a fair agreement with experimental data in combination with the two flow stress models, i.e., Johnson-Cook model and modified Johnson-Cook model.

Novel and simplified optimisation pathway using response surface and design of experiments methodologies for dental implants based on the stress of the cortical bone

2021 ◽  
pp. 095441192110253
Author(s):  
João PO Freitas ◽  
Bruno Agostinho Hernandez ◽  
Paulo J Paupitz Gonçalves ◽  
Edmea C Baptista ◽  
Edson A Capello Sousa
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Design Of Experiments ◽  
Cortical Bone ◽  
Response Surface ◽  
Dental Implants ◽  
Finite Element Models ◽  
Long Term Treatment ◽  
Dimensional Finite Element ◽  
Surrounding Bone

Dental implants are widely used as a long-term treatment solution for missing teeth. A titanium implant is inserted into the jawbone, acting as a replacement for the lost tooth root and can then support a denture, crown or bridge. This allows discreet and high-quality aesthetic and functional improvement, boosting patient confidence. The use of implants also restores normal functions such as speech and mastication. Once an implant is placed, the surrounding bone will fuse to the titanium in a process known as osseointegration. The success of osseointegration is dependent on stress distribution within the surrounding bone and thus implant geometry plays an important role in it. Optimisation analyses are used to identify the geometry which results in the most favourable stress distribution, but the traditional methodology is inefficient, requiring analysis of numerous models and parameter combinations to identify the optimal solution. A proposed improvement to the traditional methodology includes the use of Design of Experiments (DOE) together with Response Surface Methodology (RSM). This would allow for a well-reasoned combination of parameters to be proposed. This study aims to use DOE, RSM and finite element models to develop a simplified optimisation analysis method for dental implant design. Drawing on data and results from previous studies, two-dimensional finite element models of a single Branemark implant, a multi-unit abutment, two prosthetic screws, a prosthetic crown and a region of mandibular bone were built. A small number of combinations of implant diameter and length were set based on the DOE method to analyse the influence of geometry on stress distribution at the bone-implant interface. The results agreed with previous studies and indicated that implant length is the critical parameter in reducing stress on cortical bone. The proposed method represents a more efficient analysis of multiple geometrical combinations with reduced time and computational cost, using fewer than a third of the models required by the traditional methods. Further work should include the application of this methodology to optimisation analyses using three-dimensional finite element models.

Age Dependent and Anisotropic Material Properties of Immature Porcine Sclera

2013 ◽  
Author(s):  
Jami M. Saffioti ◽  
Brittany Coats
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Anisotropic Material ◽  
Computational Models ◽  
Fe Model ◽  
Ocular Tissues ◽  
Load Bearing ◽  
Anisotropic Properties ◽  
Age Dependent ◽  
Testing Protocols

Current finite element (FE) models of the pediatric eye are based on adult material properties [2,3]. To date, there are no data characterizing the age dependent material properties of ocular tissues. The sclera is a major load bearing tissue and an essential component to most computational models of the eye. In preparation for the development of a pediatric FE model, age-dependent and anisotropic properties of sclera were evaluated in newborn (3–5 days) and toddler (4 weeks) pigs. Data from this study will guide future testing protocols for human pediatric specimens.

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 Cluster Analysis of Finite Element Analysis and Bone Microarchitectural Parameters Identifies Phenotypes with High Fracture Risk

2019 ◽  
Vol 105 (3) ◽  
pp. 252-262 ◽  
Author(s):  
Leo D. Westbury ◽  
Clare Shere ◽  
Mark H. Edwards ◽  
Cyrus Cooper ◽  
Elaine M. Dennison ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Cluster Analysis ◽  
Finite Element ◽  
Fracture Risk ◽  
High Fracture ◽  
Element Analysis
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