scholarly journals Finite Element Model of the Knee for Investigation of Injury Mechanisms: Development and Validation

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Ali Kiapour ◽  
Ata M. Kiapour ◽  
Vikas Kaul ◽  
Carmen E. Quatman ◽  
Samuel C. Wordeman ◽  
...  
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Knee Joint ◽  
Center Of Pressure ◽  
Fe Model ◽  
Loading Conditions ◽  
Tibiofemoral Rotation ◽  
Injury Mechanisms ◽  
Model Predictions ◽  
Tibiofemoral Kinematics

Multiple computational models have been developed to study knee biomechanics. However, the majority of these models are mainly validated against a limited range of loading conditions and/or do not include sufficient details of the critical anatomical structures within the joint. Due to the multifactorial dynamic nature of knee injuries, anatomic finite element (FE) models validated against multiple factors under a broad range of loading conditions are necessary. This study presents a validated FE model of the lower extremity with an anatomically accurate representation of the knee joint. The model was validated against tibiofemoral kinematics, ligaments strain/force, and articular cartilage pressure data measured directly from static, quasi-static, and dynamic cadaveric experiments. Strong correlations were observed between model predictions and experimental data (r > 0.8 and p < 0.0005 for all comparisons). FE predictions showed low deviations (root-mean-square (RMS) error) from average experimental data under all modes of static and quasi-static loading, falling within 2.5 deg of tibiofemoral rotation, 1% of anterior cruciate ligament (ACL) and medial collateral ligament (MCL) strains, 17 N of ACL load, and 1 mm of tibiofemoral center of pressure. Similarly, the FE model was able to accurately predict tibiofemoral kinematics and ACL and MCL strains during simulated bipedal landings (dynamic loading). In addition to minimal deviation from direct cadaveric measurements, all model predictions fell within 95% confidence intervals of the average experimental data. Agreement between model predictions and experimental data demonstrates the ability of the developed model to predict the kinematics of the human knee joint as well as the complex, nonuniform stress and strain fields that occur in biological soft tissue. Such a model will facilitate the in-depth understanding of a multitude of potential knee injury mechanisms with special emphasis on ACL injury.

Development and Verification of a Dynamic TKR Model

2002 ◽  
Author(s):  
Jason P. Halloran ◽  
Anthony J. Petrella ◽  
Paul J. Rullkoetter
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Dynamic Loading ◽  
Soft Tissues ◽  
Dynamic Models ◽  
Total Joint Replacement ◽  
Fe Model ◽  
Loading Conditions ◽  
Dynamic Loading Conditions

The success of current total knee replacement (TKR) devices is contingent on the kinematics and contact mechanics during in vivo activity. Indicators of potential clinical performance of total joint replacement devices include contact stress and area due to articulations, and tibio-femoral and patello-femoral kinematics. An effective way of evaluating these parameters during the design phase or before clinical use is via computationally efficient computer models. Previous finite element (FE) knee models have generally been used to determine contact stresses and/or areas during static or quasi-static loading conditions. The majority of knee models intended to predict relative kinematics have not been able to determine contact mechanics simultaneously. Recently, however, explicit dynamic finite element methods have been used to develop dynamic models of TKR able to efficiently determine joint and contact mechanics during dynamic loading conditions [1,2]. The objective of this research was to develop and validate an explicit FE model of a TKR which includes tibio-femoral and patello-femoral articulations and surrounding soft tissues. The six degree-of-freedom kinematics, kinetics and polyethylene contact mechanics during dynamic loading conditions were then predicted during gait simulation.

scholarly journals Subject-Specific Finite Element Modeling of the Tibiofemoral Joint Based on CT, Magnetic Resonance Imaging and Dynamic Stereo-Radiography Data in Vivo

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Robert E. Carey ◽  
Liying Zheng ◽  
Ameet K. Aiyangar ◽  
Christopher D. Harner ◽  
Xudong Zhang
Keyword(s):  
Magnetic Resonance Imaging ◽  
Finite Element ◽  
Magnetic Resonance ◽  
Contact Area ◽  
Resonance Imaging ◽  
Model Predictions ◽  
Subject Specific ◽  
Skeletal Kinematics ◽  
Tibiofemoral Kinematics

In this paper, we present a new methodology for subject-specific finite element modeling of the tibiofemoral joint based on in vivo computed tomography (CT), magnetic resonance imaging (MRI), and dynamic stereo-radiography (DSX) data. We implemented and compared two techniques to incorporate in vivo skeletal kinematics as boundary conditions: one used MRI-measured tibiofemoral kinematics in a nonweight-bearing supine position and allowed five degrees of freedom (excluding flexion-extension) at the joint in response to an axially applied force; the other used DSX-measured tibiofemoral kinematics in a weight-bearing standing position and permitted only axial translation in response to the same force. Verification and comparison of the model predictions employed data from a meniscus transplantation study subject with a meniscectomized and an intact knee. The model-predicted cartilage-cartilage contact areas were examined against “benchmarks” from a novel in situ contact area analysis (ISCAA) in which the intersection volume between nondeformed femoral and tibial cartilage was characterized to determine the contact. The results showed that the DSX-based model predicted contact areas in close alignment with the benchmarks, and outperformed the MRI-based model: the contact centroid predicted by the former was on average 85% closer to the benchmark location. The DSX-based FE model predictions also indicated that the (lateral) meniscectomy increased the contact area in the lateral compartment and increased the maximum contact pressure and maximum compressive stress in both compartments. We discuss the importance of accurate, task-specific skeletal kinematics in subject-specific FE modeling, along with the effects of simplifying assumptions and limitations.

scholarly journals A musculoskeletal finite element model of rat knee joint for evaluating cartilage biomechanics during gait

2021 ◽  
Author(s):  
Gustavo A. Orozco ◽  
Kalle Karjalainen ◽  
Eng Kuan Moo ◽  
Lauri Stenroth ◽  
Petri Tanska ◽  
...  
Keyword(s):  
Finite Element ◽  
Animal Models ◽  
Knee Joint ◽  
Gait Cycle ◽  
Numerical Models ◽  
Small Animal ◽  
Element Model ◽  
Lateral Compartment ◽  
Fe Model ◽  
Joint Injury

Abnormal loading of the knee due to injuries or obesity is thought to contribute to the development of osteoarthritis (OA). Small animal models have been used for studying OA progression mechanisms. However, numerical models to study cartilage responses under dynamic loading in preclinical animal models have not been developed. Here we present a musculoskeletal finite element (FE) model of a rat knee joint to evaluate cartilage biomechanical responses during a gait cycle. The rat knee joint geometries were obtained from a 3-D MRI dataset and the boundary conditions regarding loading in the joint were extracted from a musculoskeletal model of the rat hindlimb. The fibril-reinforced poroelastic (FRPE) properties of the rat cartilage were derived from data of mechanical indentation tests. Our numerical results showed the relevance of simulating anatomical and locomotion characteristics in the rat knee joint for estimating tissue responses such as contact pressures, stresses, strains, and fluid pressures. We found that the contact pressure and maximum principal strain were virtually constant in the medial compartment whereas they showed the highest values at the beginning of the gait cycle in the lateral compartment. Furthermore, we found that the maximum principal stress increased during the stance phase of gait, with the greatest values at midstance. We anticipate that our approach serves as a first step towards investigating the effects of gait abnormalities on the adaptation and degeneration of rat knee joint tissues and could be used to evaluate biomechanically-driven mechanisms of the progression of OA as a consequence of joint injury or obesity.

Intubation biomechanics: validation of a finite element model of cervical spine motion during endotracheal intubation in intact and injured conditions

2018 ◽  
Vol 28 (1) ◽  
pp. 10-22 ◽  
Author(s):  
Benjamin C. Gadomski ◽  
Snehal S. Shetye ◽  
Bradley J. Hindman ◽  
Franklin Dexter ◽  
Brandon G. Santoni ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Finite Element ◽  
Cervical Spine ◽  
Endotracheal Intubation ◽  
Macintosh Laryngoscope ◽  
Element Model ◽  
Fe Model ◽  
Intervertebral Motion ◽  
Model Predictions ◽  
Spine Motion

OBJECTIVEBecause of limitations inherent to cadaver models of endotracheal intubation, the authors’ group developed a finite element (FE) model of the human cervical spine and spinal cord. Their aims were to 1) compare FE model predictions of intervertebral motion during intubation with intervertebral motion measured in patients with intact cervical spines and in cadavers with spine injuries at C-2 and C3–4 and 2) estimate spinal cord strains during intubation under these conditions.METHODSThe FE model was designed to replicate the properties of an intact (stable) spine in patients, C-2 injury (Type II odontoid fracture), and a severe C3–4 distractive-flexion injury from prior cadaver studies. The authors recorded the laryngoscope force values from 2 different laryngoscopes (Macintosh, high intubation force; Airtraq, low intubation force) used during the patient and cadaver intubation studies. FE-modeled motion was compared with experimentally measured motion, and corresponding cord strain values were calculated.RESULTSFE model predictions of intact intervertebral motions were comparable to motions measured in patients and in cadavers at occiput–C2. In intact subaxial segments, the FE model more closely predicted patient intervertebral motions than did cadavers. With C-2 injury, FE-predicted motions did not differ from cadaver measurements. With C3–4 injury, however, the FE model predicted greater motions than were measured in cadavers. FE model cord strains during intubation were greater for the Macintosh laryngoscope than the Airtraq laryngoscope but were comparable among the 3 conditions (intact, C-2 injury, and C3–4 injury).CONCLUSIONSThe FE model is comparable to patients and cadaver models in estimating occiput–C2 motion during intubation in both intact and injured conditions. The FE model may be superior to cadavers in predicting motions of subaxial segments in intact and injured conditions.

Structural Response of Timber-Concrete Composite Beams Predicted by Finite Element Models and Manual Calculations

2014 ◽  
Vol 17 (11) ◽  
pp. 1601-1621 ◽  
Author(s):  
Nima Khorsandnia ◽  
Hamid Valipour ◽  
Keith Crews
Keyword(s):  
Finite Element ◽  
Axial Stress ◽  
Damage Model ◽  
Structural Response ◽  
General Purpose ◽  
Finite Element Models ◽  
Fe Model ◽  
Loading Capacity ◽  
Model Predictions ◽  
Ultimate Loading Capacity

This paper presents the structural response of timber-concrete composite (TCC) beams predicted by finite element models (i.e. continuum-based and 1D frame) and manual calculations. Details of constitutive laws adopted for modelling timber and concrete are provided and application of the Hashin damage model in conjunction with continuum-based FE for capturing failure of timber under bi-axial stress state is discussed. A simplified strategy for modelling the TCC connection is proposed in which the connection is modelled by a nonlinear spring and the full load-slip behaviour of each TCC connection is expressed with a formula that can be directly implemented in the general purpose FE codes and used for nonlinear analysis of TCC beams. The developed FE models are verified by examples taken from the literature. Furthermore, the load-displacement response and ultimate loading capacity of the TCC beams are determined according to Eurocode 5 method and compared with FE model predictions.

Finite Element Modeling of Knee Joint Contact Pressures and Comparison to Magnetic Resonance Imaging of the Loaded Knee

2003 ◽  
Author(s):  
Jiang Yao ◽  
Art D. Salo ◽  
Monica Barbu-McInnis ◽  
Amy L. Lerner
Keyword(s):  
Magnetic Resonance Imaging ◽  
Finite Element ◽  
Magnetic Resonance ◽  
Knee Joint ◽  
Material Properties ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Three Dimensional Model ◽  
Model Predictions

A finite element model of the knee joint could be helpful in providing insight on mechanisms of injury, effects of treatment, and the role of mechanical factors in degenerative conditions. However, preparation of such a model involves many geometric simplifications and input of material properties, some of which are poorly understood. Therefore, a method to compare model predictions to actual behaviors under controlled conditions could provide confidence in the model before exploration of other loading scenarios. Our laboratory has developed a method to apply axial loads to the in vivo human knee during magnetic resonance imaging, resembling weightbearing conditions. Image processing algorithms may then be used to assess the three-dimensional kinematics of the tibia and femur during loading. A three-dimensional model of the tibio-menisco-femoral contact has been generated and the image-based kinematic boundary conditions were applied to investigate the distribution of stresses and strains in the articular cartilage and menisci throughout the loading period. In this study, our goal is to investigate the contact patterns during long term loading of up to twenty minutes in the healthy knee. Specifically, we assess the use of both elastic and poroelastic material properties in the cartilage, and compare model predictions to known loading conditions and images of tissue deformations.

Damping Matrix Identification by Finite Element Model Updating Using Frequency Response Data

2017 ◽  
Vol 17 (01) ◽  
pp. 1750004 ◽  
Author(s):  
S. Pradhan ◽  
S. V. Modak
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Frequency Response ◽  
Model Updating ◽  
Experimental Studies ◽  
Element Model ◽  
Fe Model ◽  
Damping Matrix ◽  
Steel Cast ◽  
Identification Techniques

Accurate modeling of damping is essential for prediction of vibration response of a structure. This paper presents a study of damping matrix identification method using experimental data. The identification is done by performing finite element (FE) model updating using normal frequency response functions (FRFs). The paper addresses some key issues like data incompleteness and computation of the normal FRFs for carrying out the model updating using experimental data. The effect of various levels of damping in structures on the performance of the identification techniques is also investigated. Experimental studies on three beam structures made up of mild steel, cast iron and acrylic are presented to demonstrate the effectiveness of the identification techniques for different levels of damping.

Experimental Validation of a Finite Element Model of a Human Cadaveric Tibia

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Hans A. Gray ◽  
Fulvia Taddei ◽  
Amy B. Zavatsky ◽  
Luca Cristofolini ◽  
Harinderjit S Gill
Keyword(s):  
Finite Element ◽  
Knee Replacement ◽  
Experimental Validation ◽  
Regression Line ◽  
Ct Scans ◽  
Fe Model ◽  
Loading Conditions ◽  
Test Conditions ◽  
Physical Testing ◽  
Mean Square Errors

Finite element (FE) models of long bones are widely used to analyze implant designs. Experimental validation has been used to examine the accuracy of FE models of cadaveric femurs; however, although convergence tests have been carried out, no FE models of an intact and implanted human cadaveric tibia have been validated using a range of experimental loading conditions. The aim of the current study was to create FE models of a human cadaveric tibia, both intact and implanted with a unicompartmental knee replacement, and to validate the models against results obtained from a comprehensive set of experiments. Seventeen strain rosettes were attached to a human cadaveric tibia. Surface strains and displacements were measured under 17 loading conditions, which consisted of axial, torsional, and bending loads. The tibia was tested both before and after implantation of the knee replacement. FE models were created based on computed tomography (CT) scans of the cadaveric tibia. The models consisted of ten-node tetrahedral elements and used 600 material properties derived from the CT scans. The experiments were simulated on the models and the results compared to experimental results. Experimental strain measurements were highly repeatable and the measured stiffnesses compared well to published results. For the intact tibia under axial loading, the regression line through a plot of strains predicted by the FE model versus experimentally measured strains had a slope of 1.15, an intercept of 5.5 microstrain, and an R2 value of 0.98. For the implanted tibia, the comparable regression line had a slope of 1.25, an intercept of 12.3 microstrain, and an R2 value of 0.97. The root mean square errors were 6.0% and 8.8% for the intact and implanted models under axial loads, respectively. The model produced by the current study provides a tool for simulating mechanical test conditions on a human tibia. This has considerable value in reducing the costs of physical testing by pre-selecting the most appropriate test conditions or most favorable prosthetic designs for final mechanical testing. It can also be used to gain insight into the results of physical testing, by allowing the prediction of those variables difficult or impossible to measure directly.

scholarly journals Comparison of Hyperelastic Models for Rubber-Like Materials

2006 ◽  
Vol 79 (5) ◽  
pp. 835-858 ◽  
Author(s):  
G. Marckmann ◽  
E. Verron
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Constitutive Equations ◽  
Loading Conditions ◽  
Material Parameters ◽  
Fitting Procedure ◽  
Element Simulation ◽  
Different Types ◽  
Hyperelastic Models

Abstract The present paper proposes a thorough comparison of twenty hyperelastic models for rubber-like materials. The ability of these models to reproduce different types of loading conditions is analyzed thanks to two classical sets of experimental data. Both material parameters and the stretch range of validity of each model are determined by an efficient fitting procedure. Then, a ranking of these twenty models is established, highlighting new efficient constitutive equations that could advantageously replace well-known models, which are widely used by engineers for finite element simulation of rubber parts.

An Integrated Musculoskeletal-Finite-Element Model to Evaluate Effects of Load Carriage on the Tibia During Walking

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Chun Xu ◽  
Amy Silder ◽  
Ju Zhang ◽  
Julie Hughes ◽  
Ginu Unnikrishnan ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Injury Risk ◽  
Load Carriage ◽  
Body Motion ◽  
Bone Biomechanics ◽  
External Loading ◽  
Fe Model ◽  
Loading Conditions ◽  
Reaction Forces

Prior studies have assessed the effects of load carriage on the tibia. Here, we expand on these studies and investigate the effects of load carriage on joint reaction forces (JRFs) and the resulting spatiotemporal stress/strain distributions in the tibia. Using full-body motion and ground reaction forces from a female subject, we computed joint and muscle forces during walking for four load carriage conditions. We applied these forces as physiological loading conditions in a finite-element (FE) analysis to compute strain and stress. We derived material properties from computed tomography (CT) images of a sex-, age-, and body mass index-matched subject using a mesh morphing and mapping algorithm, and used them within the FE model. Compared to walking with no load, the knee JRFs were the most sensitive to load carriage, increasing by as much as 26.2% when carrying a 30% of body weight (BW) load (ankle: 16.4% and hip: 19.0%). Moreover, our model revealed disproportionate increases in internal JRFs with increases in load carriage, suggesting a coordinated adjustment in the musculature functions in the lower extremity. FE results reflected the complex effects of spatially varying material properties distribution and muscular engagement on tibial biomechanics during walking. We observed high stresses on the anterior crest and the medial surface of the tibia at pushoff, whereas high cumulative stress during one walking cycle was more prominent in the medioposterior aspect of the tibia. Our findings reinforce the need to include: (1) physiologically accurate loading conditions when modeling healthy subjects undergoing short-term exercise training and (2) the duration of stress exposure when evaluating stress-fracture injury risk. As a fundamental step toward understanding the instantaneous effect of external loading, our study presents a means to assess the relationship between load carriage and bone biomechanics.

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