scholarly journals Validation of Finite Element Predictions of Cartilage Contact Pressure in the Human Hip Joint

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Andrew E. Anderson ◽  
Benjamin J. Ellis ◽  
Steve A. Maas ◽  
Christopher L. Peters ◽  
Jeffrey A. Weiss
Keyword(s):  
Finite Element ◽  
Hip Joint ◽  
Image Data ◽  
Contact Stresses ◽  
Stair Climbing ◽  
Patient Specific ◽  
Contact Areas ◽  
Subject Specific ◽  
Peak Pressures ◽  
And Cartilage

Methods to predict contact stresses in the hip can provide an improved understanding of load distribution in the normal and pathologic joint. The objectives of this study were to develop and validate a three-dimensional finite element (FE) model for predicting cartilage contact stresses in the human hip using subject-specific geometry from computed tomography image data, and to assess the sensitivity of model predictions to boundary conditions, cartilage geometry, and cartilage material properties. Loads based on in vivo data were applied to a cadaveric hip joint to simulate walking, descending stairs, and stair-climbing. Contact pressures and areas were measured using pressure sensitive film. CT image data were segmented and discretized into FE meshes of bone and cartilage. FE boundary and loading conditions mimicked the experimental testing. Fair to good qualitative correspondence was obtained between FE predictions and experimental measurements for simulated walking and descending stairs, while excellent agreement was obtained for stair-climbing. Experimental peak pressures, average pressures, and contact areas were 10.0MPa (limit of film detection), 4.4–5.0MPa, and 321.9–425.1mm2, respectively, while FE-predicted peak pressures, average pressures, and contact areas were 10.8–12.7MPa, 5.1–6.2MPa, and 304.2–366.1mm2, respectively. Misalignment errors, determined as the difference in root mean squared error before and after alignment of FE results, were less than 10%. Magnitude errors, determined as the residual error following alignment, were approximately 30% but decreased to 10–15% when the regions of highest pressure were compared. Alterations to the cartilage shear modulus, bulk modulus, or thickness resulted in ±25% change in peak pressures, while changes in average pressures and contact areas were minor (±10%). When the pelvis and proximal femur were represented as rigid, there were large changes, but the effect depended on the particular loading scenario. Overall, the subject-specific FE predictions compared favorably with pressure film measurements and were in good agreement with published experimental data. The validated modeling framework provides a foundation for development of patient-specific FE models to investigate the mechanics of normal and pathological hips.

An Enhanced Discrete Element Model for Predicting Hip Contact Stresses

2012 ◽  
Author(s):  
Christine L. Abraham ◽  
Steve A. Maas ◽  
Jeffrey A. Weiss ◽  
Benjamin J. Ellis ◽  
Christopher L. Peters ◽  
...  
Keyword(s):  
Hip Joint ◽  
Contact Stress ◽  
Element Model ◽  
Discrete Element ◽  
Contact Stresses ◽  
Fe Method ◽  
Element Analysis ◽  
Dea Model ◽  
Subject Specific ◽  
And Cartilage

Chronic exposure to excessive stress on articular cartilage in the hip joint predicts the progression and onset of osteoarthritis (OA) [1]. Discrete element analysis (DEA) has been used to predict cartilage contact stresses [2, 3]. Because of its low computational expense and relative ease of application, DEA could be an effective alternative to the finite element (FE) method for the study of contact stresses in the hip. Previous DEA models have assumed concentric hip joint geometry and constant cartilage thickness. These assumptions lead to underestimates for cartilage contact stress and predict unrealistic, simplified contact patterns [2, 4]. It is possible that DEA could provide more realistic predictions of cartilage contact stress if subject-specific bone and cartilage geometry were used. The objectives of this study were to develop a DEA model that accommodates subject-specific bone and cartilage geometry, and to compare DEA model predictions of cartilage contact stresses with predictions from validated FE models.

Quantitative Analysis of Incongruity, Contact Areas and Cartilage Thickness in the Human Hip Joint

1997 ◽  
Vol 158 (3) ◽  
pp. 192-204 ◽  
Author(s):  
F. Eckstein ◽  
R.v. Eisenhart-Rothe ◽  
J. Landgraf ◽  
C. Adam ◽  
F. Loehe ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Hip Joint ◽  
Cartilage Thickness ◽  
Contact Areas ◽  
And Cartilage

Accurate Arthroscopic Cam Resection Normalizes Contact Stresses in Patients With Femoroacetabular Impingement

2020 ◽  
Vol 49 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Jan Van Houcke ◽  
Vikas Khanduja ◽  
Emmanuel A. Audenaert
Keyword(s):  
Femoroacetabular Impingement ◽  
Hip Joint ◽  
Contact Stress ◽  
Morphological Characteristics ◽  
Contact Stresses ◽  
Patient Specific ◽  
Control Group ◽  
Joint Contact ◽  
Hip Rotation ◽  
Cam Resection

Background: Femoroacetabular impingement (FAI) is increasingly recognized as a cause of hip pain in young adults. The condition leads to chondrolabral separation and chondral delamination and eventually predisposes to osteoarthritis of the hip. FAI that inflicts cartilage damage has been observed in hips with abnormal morphological characteristics and is related to a long-term evolution toward osteoarthritis. Arthroscopic surgery, which allows for correction of morphological characteristics and restores impingement-free motions, is the current standard of treatment. Hypothesis: Arthroscopic cam resection can restore the normal mechanical environment of the hip joint in cam-type FAI. Study Design: Descriptive laboratory study. Methods: Patient-specific discrete element models from 10 patients with cam-type FAI (all male; age, 18-40 years) were defined based on preoperative computed tomography scans and postoperative magnetic resonance imaging (MRI) scans. Complete cam resection postoperatively on MRI was confirmed with alpha angles <55°. The preoperative and postoperative peak contact stress findings during impingement testing were compared against a matched control group. Results: Peak contact stress was significantly elevated in patients with cam-type FAI during impingement testing, with increasing amounts of internal hip rotation (26.6 ± 11.64 MPa in cam patients preoperatively, 12.1 ± 4.62 MPa in those same patients postoperatively, and 11.4 ± 1.72 MPa in the virtual control group during impingement testing at 20° of internal hip rotation; P < .01). This effect was normalized after arthroscopic cam resection and loading patterns matched those of the control group. Conclusion: Accurate arthroscopic cam resection restored the normal peak joint contact stresses in the hip joint. This highlights the importance of early and complete cam resections in the face of a positive diagnosis of cam-type FAI. Clinical Relevance: Treatment of cam-type FAI effectively normalizes hip joint contact mechanics.

An investigation on mechanical failure of hip joint using finite element method

2015 ◽  
Vol 60 (6) ◽  
Author(s):  
Hasan Sofuoglu ◽  
Mehmet Emin Cetin
Keyword(s):  
Finite Element ◽  
Hip Joint ◽  
Cement Mantle ◽  
Mechanical Failure ◽  
Stair Climbing ◽  
Stress Distributions ◽  
Activity Types ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Cemented Total Hip Arthroplasty

AbstractThe aim of this work was to study how the stress distributions of the hip joint’s components were changed if the activity was switched from walking to stair climbing for three different prostheses types subjected to either concentrated or distributed load. In the scope of the study, three different cemented prostheses, namely, Charnley, Muller, and Hipokrat were used for cemented total hip arthroplasty (THA) reconstruction. The finite element modeling of the hip joint with prosthesis was developed for both hip contact and muscle forces during walking and stair climbing activities. The finite element analyses were then pursued for both concentrated and distributed loading conditions applied statically on these models. Maximum von Mises stresses and strains occurred on the cortical and trabecular layers of bones; prosthesis and cement mantle were determined in order to investigate the mechanical failure of cemented THA reconstruction subjected to the different femoral loading and the activity conditions. This study showed that prosthesis, loading, and activity types had a significant effect on the stresses of components of the hip joint utilized for predicting mechanical failure of the cemented THA reconstruction.

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.

Modelling cement augmentation: A comparative experimental and finite element study at the continuum level

2009 ◽  
Vol 224 (7) ◽  
pp. 903-911 ◽  
Author(s):  
Y Zhao ◽  
Z M Jin ◽  
R K Wilcox
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Computational Models ◽  
Image Data ◽  
Fe Model ◽  
Micro Computed Tomography ◽  
Synthetic Bone ◽  
Pmma Bone Cement ◽  
Subject Specific ◽  
Cent Error

Subject-specific computational models of anatomical components can now be generated from image data and used in the assessment of orthopaedic interventions. However, little work has been undertaken to model cement-augmented bone using these methods. The purpose of this study was to investigate different methods of representing a trabecular-like material (open-cell polyurethane foam, Sawbone, Sweden) augmented with poly(methyl methacrylate) (PMMA) bone cement in a finite element (FE) model. Three sets of specimens (untreated, fully augmented with cement, partially augmented with cement) were imaged using micro computed tomography (μCT) and tested under axial compression. Subject-specific continuum level FE models were built based on the μCT images. Using the first two sets of models, the material conversion factors between image greyscale and mechanical properties for the pure synthetic bone and cement-augmented composite were determined iteratively by matching the FE predictions to the experimental measurements. By applying these greyscale related mechanical properties to the FE models of the partially augmented specimens, the predicted stiffness was found to be more accurate (∼ 5 per cent error) than using homogeneous properties for the augmented and synthetic bone regions (∼ 18 per cent error). It was also found that the predicted stiffness using the modulus of pure cement to define the augmented region was overestimated, and generally the apparent elastic modulus was dominated by the properties of the synthetic bone.

Patient Specific Finite Element Modeling of a Human Skull

2006 ◽  
Vol 49 ◽  
pp. 227-234 ◽  
Author(s):  
Norio Inou ◽  
Michihiko Koseki ◽  
Koutarou Maki
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Image Data ◽  
Element Model ◽  
Biomechanical Study ◽  
Modeling Method ◽  
Patient Specific ◽  
Human Skull ◽  
Element Modeling

This paper presents automated finite element modeling method and application to a biomechanical study. The modeling method produces a finite element model based on the multi-sliced image data adaptively controlling the element size according to complexity of local bony shape. The method realizes a compact and precise finite element model with a desired total number of nodal points. This paper challenges to apply this method to a human skull because of its intricate structure. To accomplish the application of the human skull, we analyze characteristics of bony shape for a mandible and a skull. Using the analytical results, we demonstrate that the proposed modeling method successfully generates a precise finite element model of the skull with fine structures.

Patient-specific finite element modeling of respiratory lung motion using 4D CT image data

2009 ◽  
Vol 36 (5) ◽  
pp. 1500-1511 ◽  
Author(s):  
René Werner ◽  
Jan Ehrhardt ◽  
Rainer Schmidt ◽  
Heinz Handels
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Image Data ◽  
Patient Specific ◽  
Ct Image ◽  
4D Ct ◽  
Element Modeling ◽  
Lung Motion
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