scholarly journals Simulating the Growth of Articular Cartilage Explants in a Permeation Bioreactor to Aid in Experimental Protocol Design

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Timothy P. Ficklin ◽  
Andrew Davol ◽  
Stephen M. Klisch
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Articular Cartilage ◽  
Element Model ◽  
Cartilage Explants ◽  
Solid Matrix ◽  
Cartilage Growth ◽  
Growth Laws ◽  
Competing Hypotheses

Recently a cartilage growth finite element model (CGFEM) was developed to solve nonhomogeneous and time-dependent growth boundary-value problems (Davol et al., 2008, “A Nonlinear Finite Element Model of Cartilage Growth,” Biomech. Model. Mechanobiol., 7, pp. 295–307). The CGFEM allows distinct stress constitutive equations and growth laws for the major components of the solid matrix, collagens and proteoglycans. The objective of the current work was to simulate in vitro growth of articular cartilage explants in a steady-state permeation bioreactor in order to obtain results that aid experimental design. The steady-state permeation protocol induces different types of mechanical stimuli. When the specimen is initially homogeneous, it directly induces homogeneous permeation velocities and indirectly induces nonhomogeneous solid matrix shear stresses; consequently, the steady-state permeation protocol is a good candidate for exploring two competing hypotheses for the growth laws. The analysis protocols were implemented through the alternating interaction of the two CGFEM components: poroelastic finite element analysis (FEA) using ABAQUS and a finite element growth routine using MATLAB. The CGFEM simulated 12 days of growth for immature bovine articular cartilage explants subjected to two competing hypotheses for the growth laws: one that is triggered by permeation velocity and the other by maximum shear stress. The results provide predictions for geometric, biomechanical, and biochemical parameters of grown tissue specimens that may be experimentally measured and, consequently, suggest key biomechanical measures to analyze as pilot experiments are performed. The combined approach of CGFEM analysis and pilot experiments may lead to the refinement of actual experimental protocols and a better understanding of in vitro growth of articular cartilage.

Finite Element Formulation of Biphasic Poroviscoelastic Model for Articular Cartilage

1998 ◽  
Vol 120 (2) ◽  
pp. 195-201 ◽  
Author(s):  
Jun-Kyo Suh ◽  
Shi Bai
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Discrete Spectrum ◽  
Element Model ◽  
Solid Matrix ◽  
Element Formulation ◽  
Confined Compression ◽  
Computationally Efficient ◽  
Relaxation Responses ◽  
Creep And Stress Relaxation

The purpose of the present study was to develop a computationally efficient finite element model that could be useful for parametric analysis of the biphasic poroviscoelastic (BPVE) behavior of articular cartilage under various loading conditions. The articular cartilage was modeled as the BPVE mixture of a porous, linear viscoelastic, and incompressible solid and an inviscid and incompressible fluid. A finite element (FE) formulation of the BPVE model was developed using two different algorithms, the continuous and discrete spectrum relaxation functions for the viscoelasticity of the solid matrix. These algorithms were applied to the creep and stress relaxation responses to the confined compression of articular cartilage, and a comparison of their performances was made. It was found that the discrete spectrum algorithm significantly saved CPU time and memory, as compared to the continuous spectrum algorithm. The consistency analysis for the present FE formulation was performed in comparison with the IMSL, a commercially available numerical software package. It was found that the present FE formulation yielded consistent results in predicting model behavior, whereas the IMSL subroutine produced inconsistent results in the velocity field, and thereby in the strain calculation.

scholarly journals Biomechanical characteristics of tibio-femoral joint after partial medial meniscectomy in different flexion angles: a finite element analysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaohui Zhang ◽  
Shuo Yuan ◽  
Jun Wang ◽  
Bagen Liao ◽  
De Liang
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Finite Element Model ◽  
Medial Meniscus ◽  
Lateral Meniscus ◽  
Element Model ◽  
Magnetic Resonance Images ◽  
Biomechanical Analysis ◽  
Joint Stress ◽  
Tibiofemoral Joint

Abstract Background Recent studies have pointed out that arthroscopy, the commonly-used surgical procedure for meniscal tears, may lead to an elevated risk of knee osteoarthritis (KOA). The biomechanical factors of KOA can be clarified by the biomechanical analysis after arthroscopic partial meniscectomy (APM). This study aimed to elucidate the cartilage stress and meniscus displacement of the tibiofemoral joint under flexion and rotation loads after APM. Methods A detailed finite element model of the knee bone, cartilage, meniscus, and major ligaments was established by combining computed tomography and magnetic resonance images. Vertical load and front load were applied to simulate different knee buckling angles. At the same time, by simulating flexion of different degrees and internal and external rotations, the stresses on tibiofemoral articular cartilage and meniscus displacement were evaluated. Results Generally, the contact stress on both the femoral tibial articular cartilage and the meniscus increased with the increased flexion degree. Moreover, the maximum stress on the tibial plateau gradually moved backward. The maximum position shift value of the lateral meniscus was larger than that of the medial meniscus. Conclusion Our finite element model provides a realistic three-dimensional model to evaluate the influence of different joint range of motion and rotating tibiofemoral joint stress distribution. The decreased displacement of the medial meniscus may explain the higher pressure on the knee components. These characteristics of the medial tibiofemoral joint indicate the potential biomechanical risk of knee degeneration.

A Finite Element Model of the Human Knee Joint for the Study of Tibio-Femoral Contact

2002 ◽  
Vol 124 (3) ◽  
pp. 273-280 ◽  
Author(s):  
Tammy L. Haut Donahue ◽  
M. L. Hull ◽  
Mark M. Rashid ◽  
Christopher R. Jacobs
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Three Dimensional ◽  
Element Model ◽  
Maximum Pressure ◽  
Contact Behavior ◽  
Element Size ◽  
Solid Models ◽  
Flexion Extension ◽  
Three Dimensional Coordinate

As a step towards developing a finite element model of the knee that can be used to study how the variables associated with a meniscal replacement affect tibio-femoral contact, the goals of this study were 1) to develop a geometrically accurate three-dimensional solid model of the knee joint with special attention given to the menisci and articular cartilage, 2) to determine to what extent bony deformations affect contact behavior, and 3) to determine whether constraining rotations other than flexion/extension affects the contact behavior of the joint during compressive loading. The model included both the cortical and trabecular bone of the femur and tibia, articular cartilage of the femoral condyles and tibial plateau, both the medial and lateral menisci with their horn attachments, the transverse ligament, the anterior cruciate ligament, and the medial collateral ligament. The solid models for the menisci and articular cartilage were created from surface scans provided by a noncontacting, laser-based, three-dimensional coordinate digitizing system with an root mean squared error (RMSE) of less than 8 microns. Solid models of both the tibia and femur were created from CT images, except for the most proximal surface of the tibia and most distal surface of the femur which were created with the three-dimensional coordinate digitizing system. The constitutive relation of the menisci treated the tissue as transversely isotropic and linearly elastic. Under the application of an 800 N compressive load at 0 degrees of flexion, six contact variables in each compartment (i.e., medial and lateral) were computed including maximum pressure, mean pressure, contact area, total contact force, and coordinates of the center of pressure. Convergence of the finite element solution was studied using three mesh sizes ranging from an average element size of 5 mm by 5 mm to 1 mm by 1 mm. The solution was considered converged for an average element size of 2 mm by 2 mm. Using this mesh size, finite element solutions for rigid versus deformable bones indicated that none of the contact variables changed by more than 2% when the femur and tibia were treated as rigid. However, differences in contact variables as large as 19% occurred when rotations other than flexion/extension were constrained. The largest difference was in the maximum pressure. Among the principal conclusions of the study are that accurate finite element solutions of tibio-femoral contact behavior can be obtained by treating the bones as rigid. However, unrealistic constraints on rotations other than flexion/extension can result in relatively large errors in contact variables.

BIOMECHANICAL BEHAVIOUR OF BOVINE SKIN: AN EXPERIMENT-THEORY INTEGRATION AND FINITE ELEMENT SIMULATION

2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Nor Fazli Adull Manan ◽  
Jamaluddin Mahmud ◽  
Aidah Jumahat
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Deformation Behaviour ◽  
Element Model ◽  
Tensile Tests ◽  
Theory Integration ◽  
Element Simulation ◽  
Knowledge Enhancement ◽  
First Time

This paper for the first time attempts to establish the biomechanical characteristics of bovine skin via experiment-theory integration and finite element simulation. 30 specimens prepared from fresh slaughtered bovine were uniaxially stretched in-vitro using tensile tests machine. The experimental raw data are then input into a Matlab programme, which quantified the hyperelastic parameters based on Ogden constitutive equation. It is found that the Ogden coefficient and exponent for bovine skin are μ = 0.017 MPa and α = 11.049 respectively. For comparison of results, the quantified Ogden parameters are then input into a simple but robust finite element model, which is developed to replicate the experimental setup and simulate the deformation of the bovine skin. Results from experiment-theory integration and finite element simulation are compared. It is found that the stress-stretch curves are close to one another. The results and finding prove that the current study is significant and has contributed to knowledge enhancement about the deformation behaviour of bovine skin.

Nanocomposites Based on Multiwalled Carbon Nanotubes With Effective Young’s Modulus Dependent on Number of Layers

2014 ◽  
Author(s):  
Preeti Joshi ◽  
S. H. Upadhyay
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Multiwalled Carbon Nanotubes ◽  
Matrix Material ◽  
Tensile Modulus ◽  
Element Model ◽  
Solid Matrix ◽  
Multiwalled Carbon ◽  
Number Of Layers ◽  
Transverse Modulus

The excellent combination of high strength, stiffness, low density and aspect ratio makes carbon nanotubes ideal reinforcement for nanocomposites. The load transfer between the outer and inner layers of multiwalled carbon nanotubes (MWCNT) is one of the important factor in the reinforcement of nanocomposites. In this work, the effect of variation in number of layers of multiwalled carbon nanotubes on effective tensile, compressive and transverse modulus of composite is evaluated. A 3-D finite element model based on representative volume element, consisting of multiwalled carbon nanotube made of shell elements surrounded by solid matrix material is built. With the increase in number of layers in multiwalled carbon nanotubes, the compressive modulus of composite increases, while the tensile modulus decreases. The transverse modulus of composite is found to increase, with the increase in number of layers in MWCNT. The finite element results for composite are compared with the rule of mixtures results using formulae.

Differential Regulation of Articular Cartilage Biomechanical and Biochemical Properties by IGF-1 and TGF-β1 During In Vitro Growth

2009 ◽  
Author(s):  
Michael E. Stender ◽  
Christian R. Flores ◽  
Kristin J. Dills ◽  
Gregory M. Williams ◽  
Kevin M. Stewart ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Growth Models ◽  
Biochemical Properties ◽  
Low Friction ◽  
Cartilage Growth ◽  
Detailed Characterization ◽  
Naturally Occurring ◽  
Tgf Β1

Articular cartilage (AC) is a load bearing material that provides a low friction wear resistant interface in synovial joints. Naturally-occurring and stimulated intrinsic repair of damaged AC is ineffective. Thus, there is a desire to engineer effective replacement tissue that could be used for AC repair. Previous studies [1] have shown that culture of immature cartilage with medium including TGF-β1 will result in a more mature tissue than culture with IGF-1. Detailed characterization of tissue mechanical properties would be helpful for development of cartilage growth models [2].

Strain Measurement in Coronary Arteries Using Intravascular Ultrasound and Deformable Images

2002 ◽  
Vol 124 (6) ◽  
pp. 734-741 ◽  
Author(s):  
Alexander I. Veress ◽  
Jeffrey A. Weiss ◽  
Grant T. Gullberg ◽  
D. Geoffrey Vince ◽  
Richard D. Rabbitt
Keyword(s):  
Finite Element ◽  
Intravascular Ultrasound ◽  
Coronary Arteries ◽  
Strain Distribution ◽  
Plaque Rupture ◽  
Element Model ◽  
Cross Sectional ◽  
Image Pairs

Atherosclerotic plaque rupture is responsible for the majority of myocardial infarctions and acute coronary syndromes. Rupture is initiated by mechanical failure of the plaque cap, and thus study of the deformation of the plaque in the artery can elucidate the events that lead to myocardial infarction. Intravascular ultrasound (IVUS) provides high resolution in vitro and in vivo cross-sectional images of blood vessels. To extract the deformation field from sequences of IVUS images, a registration process must be performed to correlate material points between image pairs. The objective of this study was to determine the efficacy of an image registration technique termed Warping to determine strains in plaques and coronary arteries from paired IVUS images representing two different states of deformation. The Warping technique uses pointwise differences in pixel intensities between image pairs to generate a distributed body force that acts to deform a finite element model. The strain distribution estimated by image-based Warping showed excellent agreement with a known forward finite element solution, representing the gold standard, from which the displaced image was created. The Warping technique had a low sensitivity to changes in material parameters or material model and had a low dependency on the noise present in the images. The Warping analysis was also able to produce accurate strain distributions when the constitutive model used for the Warping analysis and the forward analysis was different. The results of this study demonstrate that Warping in conjunction with in vivo IVUS imaging will determine the change in the strain distribution resulting from physiological loading and may be useful as a diagnostic tool for predicting the likelihood of plaque rupture through the determination of the relative stiffness of the plaque constituents.

scholarly journals Effect of GCSB-5, a Herbal Formulation, on Monosodium Iodoacetate-Induced Osteoarthritis in Rats

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Joon-Ki Kim ◽  
Sang-Won Park ◽  
Jung-Woo Kang ◽  
Yu-Jin Kim ◽  
Sung Youl Lee ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Protein Expression ◽  
Nuclear Factor Κb ◽  
Interleukin 10 ◽  
Cartilage Explants ◽  
Therapeutic Effects ◽  
Monosodium Iodoacetate ◽  
Factor Α

Therapeutic effects of GCSB-5 on osteoarthritis were measured by the amount of glycosaminoglycan in rabbit articular cartilage explantsin vitro, in experimental osteoarthritis induced by intra-articular injection of monoiodoacetate in ratsin vivo. GCSB-5 was orally administered for 28 days.In vitro, GCSB-5 inhibited proteoglycan degradation. GCSB-5 significantly suppressed the histological changes in monoiodoacetate-induced osteoarthritis. Matrix metalloproteinase (MMP) activity, as well as, the levels of serum tumor necrosis factor-α, cyclooxygenase-2, inducible nitric oxide synthase protein, and mRNA expressions were attenuated by GCSB-5, whereas the level of interleukin-10 was potentiated. By GCSB-5, the level of nuclear factor-κB p65 protein expression was significantly attenuated but, on the other hand, the level of inhibitor of κB-α protein expression was increased. These results indicate that GCSB-5 is a potential therapeutic agent for the protection of articular cartilage against progression of osteoarthritis through inhibition of MMPs activity, inflammatory mediators, and NF-κB activation.

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