Development of Human Lower Limb and Pelvis FE Models for Adult and the Elderly

Dokko, Yasuhiro; Ito, Osamu; Ohashi, Katsuhisa

doi:10.4271/2009-01-0396

Cited by 18 publications

(5 citation statements)

References 17 publications

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“…Specific age-based models that have been developed can be improved by incorporating accurate rib cortical thickness data collected from clinical-CT scans [16,18,21,22,46]. A clinical application of the CDM algorithm would be to apply the methods presented to a wide range of ages and regress rib cortical thickness with age and use the results to improve existing age-based regression functions in the literature [47]. Normative data on rib cortical thickness with age and sex would be valuable to surgical device design (e.g.…”

Section: Discussionmentioning

confidence: 99%

Comparing rib cortical thickness measurements from computed tomography (CT) and Micro-CT

Hostetler

Stitzel

Weaver

2019

Computers in Biology and Medicine

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Background: The objective of this study was to compare cortical thickness of rib specimens scanned with clinical computed tomography (clinical-CT) at 0.5 and 1.0 mm slice thickness versus micro-CT at 0.05 mm slice thickness. Cortical thickness variation and accuracy was explored by anatomical region (anterior vs. lateral) and cross-sectional quadrants (superior, interior, inferior, and exterior). Methods: A validated cortical thickness algorithm was applied to clinical-CT and micro-CT scans of 17 rib specimens from six male post mortem human subjects aged 42–81 years. Each rib specimen was segmented and the thickness measurements were partitioned into cross-sectional quadrants in the anterior and lateral regions of the rib. Within each rib quadrant, the following were calculated: average thickness ± standard deviation, mean thickness difference between clinical-CT and micro-CT, and a thickness ratio between clinical-CT and micro-CT. Correlations from linear regression and paired-t tests were determined for paired clinical-CT and micro-CT results. Results: On average, the 0.5 mm clinical-CT underestimated the micro-CT thickness by 0.005 mm, while the 1.0 mm clinical-CT overestimated the micro-CT thickness by 0.149 mm. Thickness derived from 0.5 mm clinical-CT showed greater significant linear correlations (p < 0.05) with micro-CT thickness compared to 1.0 mm clinical-CT. Conclusions: The small mean differences and thickness ratios near 1 show validation for the cortical thickness algorithm when applied to rib clinical-CT scans. Using clinical-CT scans as way to accurately measure rib cortical thickness offers a non-invasive way to analyze millions of CT scans collected each year from males and females of all ages.

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Section: Discussionmentioning

confidence: 99%

Comparing rib cortical thickness measurements from computed tomography (CT) and Micro-CT

Hostetler

Stitzel

Weaver

2019

Computers in Biology and Medicine

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“…The Young's and shear modulus of the cortical bone was reduced by 3 and 4% per decade of age, respectively (Burstein et al, 1976). The ultimate strain was decreased by 10% of the initial value per decade, and yield properties were remained constant during aging (Reilly et al, 1974;Reilly and Burstein 1975;Martin 1993;Dokko et al, 2009;Kutz 2009;Mirzaali et al, 2016). Likewise, the modulus of elasticity and yield stresses of the trabecular bone were reduced 17 and 1.09 MPa, respectively, per decade of age (Mosekilde et al, 1987;Keaveny, 1998).…”

Section: Aging Effectsmentioning

confidence: 99%

“…In the femoral neck, the cortical bone loses stiffness in terms of Young's and shear modulus by 3 and 4% per decade of age, respectively. Ultimate strains decrease about 5-10% of the initial value per decade while yield properties of the bone do not change significantly with age (Reilly et al, 1974;Reilly and Burstein 1975;Martin 1993;Dokko et al, 2009;Kutz 2009;Mirzaali et al, 2016;Osterhoff et al, 2016). Those changes, combined, cause a transition from a ductile bone to a more brittle one with age (Ott et al, 2010).…”

Section: Introductionmentioning

confidence: 98%

Separate and Combined Effects of Geometrical and Mechanical Properties Changes Due to Aging on the Femoral Strength in Men and Women

Sahandifar

Kleiven

2021

Front. Mech. Eng.

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Aging, from 40 to +80 years old, causes geometrical and mechanical properties changes in the proximal femur. The subperiosteal width expands faster in men compared to women during aging, while the cortical thickness varies unequally in each sector and differently between men and women. Another change which occurs during aging is bone mechanical properties such as stiffness and ultimate strains. Numerical analysis allows us to study the potential effects of each of the age-dependent changes on the fracture forces separately and combined. We investigated the effects of the geometrical and bone mechanical properties changes due to aging on the femoral strength during a common falling scenario using a transverse isotropic continuum damage model. First, the femur model was adapted from a previously developed human body model named THUMS v4.02. Then, three sets of models were developed to address each of the changes separately and combined for both sexes. We found that the fracture forces in women are on average 1500 N less than in men of the same age. The age-dependent geometrical changes increased the fracture forces in men (25 N/decade), whereas it reduced the fracture forces by 116 N/decade in women. The mechanical properties changes reduced the fracture forces in men more than in women (354.5 N/ decade vs. 225.4 N/decade). When accounting for both geometrical and mechanical properties changes due to aging, the fracture forces decreased by 10.7% of the baseline in women per decade compared to 7.2% per decade in men.

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“…Cortical bone thickness (Stein and Granik 1976) and ultimate stress (Burstein et al 1976;Dokko et al 2009;Yamada and Evans 1970) decrease with age. Ito et al (2009) proposed scaling factors for rib cortical bone thickness as a function of age based on Stein et al (1976) and bone material properties from elderly to adults by increasing elastic modulus and plastic stress in tandem.…”

Section: Scaling the New Model To The Am50 Size And Implementation Ofmentioning

confidence: 99%

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

Antona‐Makoshi

Yamamoto

Kato

et al. 2015

Traffic Injury Prevention

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Objectives:The ultimate goal of this research is to reduce thoracic injuries due to traffic crashes, especially in the elderly. The specific objective is to develop and validate a full-body finite element model under 2 distinct settings that account for factors relevant for thoracic fragility of elderly: one setting representative of an average size male and one representative of an average size Japanese elderly male.Methods: A new thorax finite element model was developed from medical images of a 71-year-old average Japanese male elderly size (161cm, 60 kg) postmortem human subject (PMHS). The model was validated at component and assembled levels against original series of published test data obtained from the same elderly specimen. The model was completed with extremities and head of a model previously developed. The rib cage and the thoracic flesh materials were assigned age-dependent properties and the model geometry was scaled up to simulate a 50th percentile male. Thereafter, the model was validated against existing biomechanical data for younger and elderly subjects, including hub-to-thorax impacts and frontal impact sled PMHS test data. Finally, a parametric study was conducted with the new models to understand the effect of size and aging factors on thoracic response and risk of rib fractures.Results: The model behaved in agreement with tabletop test experiments in intact, denuded, and eviscerated tissue conditions. In frontal impact sled conditions, the model showed good 3-dimensional head and spine kinematics, as well as rib cage multipoint deflections. When properties representative of an aging person were simulated, both the rib cage deformation and the predicted number of rib fractures increased. The effects of age factors such as rib cortical thickness, mechanical properties, and failure thresholds on the model responses were consistent with the literature. Aged and thereby softened flesh reduced load transfer between ribs; the coupling of the rib cage was reduced. Aged costal cartilage increased the severity of the diagonal belt loading sustained by the lower loaded rib cage.Conclusions: When age-specific parameters were implemented in a finite element (FE) model of the thorax, the rib cage kinematics and thorax injury risk increased. When the effect of size was isolated, 2 factors, in addition to rib material properties, were found to be important: flesh and costal cartilage properties. These 2 were identified to affect rib cage deformation mechanisms and may potentially increase the risk of rib fractures.

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Development of Human Lower Limb and Pelvis FE Models for Adult and the Elderly

Cited by 18 publications

References 17 publications

Comparing rib cortical thickness measurements from computed tomography (CT) and Micro-CT

Comparing rib cortical thickness measurements from computed tomography (CT) and Micro-CT

Separate and Combined Effects of Geometrical and Mechanical Properties Changes Due to Aging on the Femoral Strength in Men and Women

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

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