Elevated Joint Contact Forces in ACL-Reconstructed Knees: A Finite Element Analysis Driven by In Vivo Kinematic Data

2003 ◽  
Author(s):  
George Papaioannou ◽  
William Anderst ◽  
Scott Tashman
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Knee Kinematics ◽  
Poor Quality ◽  
Contact Forces ◽  
Element Analysis ◽  
Human Cartilage ◽  
Joint Contact ◽  
Contact Pressures

Assessment of in vivo human cartilage loading generally requires computer modeling, since loads usually cannot be directly measured. The utility of these models for assessing knee behavior during complex activities has been limited by the relatively poor quality of experimental data on in vivo knee function. We have developed a method combining high-accuracy knee kinematics (from high-speed stereo-radiography) with subject-specific finite-element models to estimate in vivo cartilage contact pressures during stressful tasks. When applied to ACL reconstruction, significantly higher contact pressures were found in reconstructed knees as compared to the contralateral (uninjured) knees of the same individuals.

A Subject-Specific Musculoskeletal Modeling Framework to Predict In Vivo Mechanics of Total Knee Arthroplasty

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Marco A. Marra ◽  
Valentine Vanheule ◽  
René Fluit ◽  
Bart H. F. J. M. Koopman ◽  
John Rasmussen ◽  
...  
Keyword(s):  
Knee Kinematics ◽  
Contact Forces ◽  
Grand Challenge ◽  
Modeling Framework ◽  
Trial Simulation ◽  
Subject Specific ◽  
Joint Contact ◽  
Total Knee ◽  
The Right

Musculoskeletal (MS) models should be able to integrate patient-specific MS architecture and undergo thorough validation prior to their introduction into clinical practice. We present a methodology to develop subject-specific models able to simultaneously predict muscle, ligament, and knee joint contact forces along with secondary knee kinematics. The MS architecture of a generic cadaver-based model was scaled using an advanced morphing technique to the subject-specific morphology of a patient implanted with an instrumented total knee arthroplasty (TKA) available in the fifth “grand challenge competition to predict in vivo knee loads” dataset. We implemented two separate knee models, one employing traditional hinge constraints, which was solved using an inverse dynamics technique, and another one using an 11-degree-of-freedom (DOF) representation of the tibiofemoral (TF) and patellofemoral (PF) joints, which was solved using a combined inverse dynamic and quasi-static analysis, called force-dependent kinematics (FDK). TF joint forces for one gait and one right-turn trial and secondary knee kinematics for one unloaded leg-swing trial were predicted and evaluated using experimental data available in the grand challenge dataset. Total compressive TF contact forces were predicted by both hinge and FDK knee models with a root-mean-square error (RMSE) and a coefficient of determination (R2) smaller than 0.3 body weight (BW) and equal to 0.9 in the gait trial simulation and smaller than 0.4 BW and larger than 0.8 in the right-turn trial simulation, respectively. Total, medial, and lateral TF joint contact force predictions were highly similar, regardless of the type of knee model used. Medial (respectively lateral) TF forces were over- (respectively, under-) predicted with a magnitude error of M < 0.2 (respectively > −0.4) in the gait trial, and under- (respectively, over-) predicted with a magnitude error of M > −0.4 (respectively < 0.3) in the right-turn trial. Secondary knee kinematics from the unloaded leg-swing trial were overall better approximated using the FDK model (average Sprague and Geers' combined error C = 0.06) than when using a hinged knee model (C = 0.34). The proposed modeling approach allows detailed subject-specific scaling and personalization and does not contain any nonphysiological parameters. This modeling framework has potential applications in aiding the clinical decision-making in orthopedics procedures and as a tool for virtual implant design.

Finite Element Analysis of In Vivo Radiocarpal Contact Mechanics Resulting From Scapholunate Ligament Injury

2012 ◽  
Author(s):  
Joshua E. Johnson ◽  
Phil Lee ◽  
Terence E. McIff ◽  
E. Bruce Toby ◽  
Kenneth J. Fischer
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Contact Forces ◽  
Computational Method ◽  
Ligament Injury ◽  
Joint Mechanics ◽  
Interosseous Ligament ◽  
Radiocarpal Joint ◽  
Contact Pressures

Secondary osteoarthritis (OA) as a result of joint injury is a significant problem. For the wrist in particular, scapholunate dissociation, resulting from injury to the scapholunate interosseous ligament (SLIL), is a commonly occurring pathology. SLIL tears can lead to scapholunate joint instability due to abnormal motion and load transfer through multiple carpal joints. If left untreated, SLIL injury has been known to progress to scapholunate advanced collapse (or SLAC wrist) with radiocarpal OA [1]. While the pathomechanics leading to the onset of OA are not clearly understood, changes in kinematics and contact mechanics with injury are believed to be causative factors. Of particular importance are joint contact pressures and pressure distributions, which are considered to be important mechanical factors. Comparing changes in joint mechanics between normal and injured wrists may help us better understand the progression of OA and improve the efficacy of corrective measures. Several techniques exist to evaluate joint mechanics. Of these, 3D image-based computational modeling is very useful to determine in vivo joint mechanics. Finite element modeling (FEM) is the most common and widely used computational method because of the ability to obtain 3D stresses and strains, and due to software availability. Therefore the objective of this study was to compare radiocarpal joint mechanics (contact forces, contact areas, contact locations, peak and average contact pressures) from FEM between normal and injured wrists. We hypothesized that peak contact pressures and average contact pressures would be higher in the injured wrists.

Tibio-Femoral Contact Force During Gait: An Iterative Method Using EMG-Constrained Multi-Body Simulation and Finite Element Analysis

2013 ◽  
Author(s):  
Silvia Pianigiani ◽  
Friedl De Groote ◽  
Lennart Scheys ◽  
Pierre Gillen ◽  
Luc Labey ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Image Data ◽  
Contact Forces ◽  
Patient Specific ◽  
Optimization Approach ◽  
Element Analysis ◽  
Force Calculation

In this study, we present an innovative methodology (Figure 1) to calculate patient specific tibio-femoral (TF) contact forces by integrating medical image data, 3D skin-mounted marker trajectories, ground reaction forces, electromyography (EMG) data and finite element analysis (FEA). The muscle redundancy problem is solved through an EMG-constrained optimization approach. Calculated muscle forces are input to a FEA to calculate TF contact forces. Kinematics of the degrees of freedom (DOFs) of the knee that cannot be accurately assessed from the trajectories of skin-mounted markers, are estimated using a novel iterative procedure which combines muscle force calculation with dynamic FEA. The presented methodology is applied to analyze TF contact forces of a walking trial performed on an instrumented treadmill of which the speed was sequentially ramped up and down. The results presented in this abstract will be validated against the in-vivo measured TF contact forces.

Effects of Surgical Repair or Reconstruction on Radiocarpal Mechanics From Wrists With Scapholunate Injury

2011 ◽  
Author(s):  
Joshua E. Johnson ◽  
Sang-Pil Lee ◽  
Terence E. McIff ◽  
E. Bruce Toby ◽  
Kenneth J. Fischer
Keyword(s):  
Contact Forces ◽  
Joint Mechanics ◽  
Imaging Data ◽  
Contact Patterns ◽  
Radiocarpal Joint ◽  
Joint Contact ◽  
Ligament Disruption ◽  
Joint Contact Pressure ◽  
Contact Pressures

Scapholunate dissociation (SL ligament disruption) due to trauma can cause changes in joint kinematics and contact patterns, which can lead to scapholunate advanced collapse (SLAC wrist) with secondary radiocarpal osteoarthritis (OA) [1]. The relationship between consequent abnormal mechanics and the onset of OA is not clearly understood, however elevated joint contact pressure is believed to be an associated factor. Knowing how injuries affect joint physiology and mechanics and how well surgical repairs restore the mechanics may improve surgical efficacy and help predict OA risk. Recently a method was proposed to measure joint contact mechanics from in vivo imaging data during functional loading [2]. The objective of this study was to compare radiocarpal joint mechanics (contact forces, contact areas, peak and average contact pressures) of injured and post-operative wrists to contralateral controls using MRI-based contact modeling. We hypothesized that average contact pressures and peak contact pressures would be higher in the injured wrists, and that these measures would decrease post-operatively.

Finite Element Analysis of Large-Size Yaw Bearings with Supporting Structure in Wind Turbine

2014 ◽  
Vol 672-674 ◽  
pp. 1550-1553
Author(s):  
Zhen Guo Shang ◽  
Zhong Chao Ma ◽  
Zhen Sheng Sun
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Point Contact ◽  
Element Model ◽  
Contact Forces ◽  
Element Analysis ◽  
Supporting Structure ◽  
Rolling Elements ◽  
Yaw Bearing ◽  
Compression Springs

A procedure for obtaining the load distribution in a four point contact wind turbine yaw bearing considering the effect of the structure’s elasticity is presented. The inhomogeneous stiffness of the supporting structures creates a variation in the results obtained with a rigid model. A finite element model substituting the rolling elements with nonlinear compression springs has been built to evaluate the effect of the supporting structure elasticity on the contact forces between the rolling elements and the raceways.

scholarly journals Computationally Efficient Magnetic Resonance Imaging Based Surface Contact Modeling as a Tool to Evaluate Joint Injuries and Outcomes of Surgical Interventions Compared to Finite Element Modeling

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Joshua E. Johnson ◽  
Phil Lee ◽  
Terence E. McIff ◽  
E. Bruce Toby ◽  
Kenneth J. Fischer
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Joint Mechanics ◽  
Computationally Efficient ◽  
Efficient Manner ◽  
Element Modeling ◽  
Joint Injuries ◽  
Surface Contact ◽  
Joint Contact ◽  
Contact Pressures

Joint injuries and the resulting posttraumatic osteoarthritis (OA) are a significant problem. There is still a need for tools to evaluate joint injuries, their effect on joint mechanics, and the relationship between altered mechanics and OA. Better understanding of injuries and their relationship to OA may aid in the development or refinement of treatment methods. This may be partially achieved by monitoring changes in joint mechanics that are a direct consequence of injury. Techniques such as image-based finite element modeling can provide in vivo joint mechanics data but can also be laborious and computationally expensive. Alternate modeling techniques that can provide similar results in a computationally efficient manner are an attractive prospect. It is likely possible to estimate risk of OA due to injury from surface contact mechanics data alone. The objective of this study was to compare joint contact mechanics from image-based surface contact modeling (SCM) and finite element modeling (FEM) in normal, injured (scapholunate ligament tear), and surgically repaired radiocarpal joints. Since FEM is accepted as the gold standard to evaluate joint contact stresses, our assumption was that results obtained using this method would accurately represent the true value. Magnetic resonance images (MRI) of the normal, injured, and postoperative wrists of three subjects were acquired when relaxed and during functional grasp. Surface and volumetric models of the radiolunate and radioscaphoid articulations were constructed from the relaxed images for SCM and FEM analyses, respectively. Kinematic boundary conditions were acquired from image registration between the relaxed and grasp images. For the SCM technique, a linear contact relationship was used to estimate contact outcomes based on interactions of the rigid articular surfaces in contact. For FEM, a pressure-overclosure relationship was used to estimate outcomes based on deformable body contact interactions. The SCM technique was able to evaluate variations in contact outcomes arising from scapholunate ligament injury and also the effects of surgical repair, with similar accuracy to the FEM gold standard. At least 80% of contact forces, peak contact pressures, mean contact pressures and contact areas from SCM were within 10 N, 0.5 MPa, 0.2 MPa, and 15 mm2, respectively, of the results from FEM, regardless of the state of the wrist. Depending on the application, the MRI-based SCM technique has the potential to provide clinically relevant subject-specific results in a computationally efficient manner compared to FEM.

Finite-Element Analysis of the Magnetostatic Field of a Coaxial Magnetic Gear Device

2015 ◽  
Vol 764-765 ◽  
pp. 289-293
Author(s):  
Yi Chang Wu ◽  
Han Ting Hsu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Magnetic Flux ◽  
High Speed ◽  
Field Analysis ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Speed Reduction ◽  
Dimensional Finite Element ◽  
Magnetic Gear

This paper presents the magnetostatic field analysis of a coaxial magnetic gear device proposed by Atallah and Howe. The structural configuration and speed reduction ratio of this magnetic gear device are introduced. The 2-dimensional finite-element analysis (2-D FEA), conducted by applying commercial FEA software Ansoft/Maxwell, is performed to evaluate the magnetostatic field distribution, especially for the magnetic flux densities within the outer air-gap. Once the number of steel pole-pieces equals the sum of the pole-pair numbers of the high-speed rotor and the low-speed rotor, the coaxial magnetic gear device possesses higher magnetic flux densities, thereby generating greater transmitted torque.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

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