Finite Element Predictions of Labrum and Cartilage Mechanics in Dysplastic Human Hips

2011 ◽  
Author(s):  
Corinne R. Henak ◽  
Ryan S. Davis ◽  
Benjamin J. Ellis ◽  
Michael D. Harris ◽  
Andrew E. Anderson ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Contact Area ◽  
Acetabular Dysplasia ◽  
Clinical Observation ◽  
Mechanical Load ◽  
Early Osteoarthritis ◽  
Cartilage Mechanics ◽  
Subject Specific ◽  
And Cartilage

Acetabular dysplasia, characterized by a shallow acetabulum and decreased coverage of the femoral head (Figure 1), is thought to cause early osteoarthritis due to altered mechanical loading. Clinical observation of hypertrophic labra in dysplastic hips suggests that the labrum supports mechanical load (e.g., [1]). Simulations have predicted increased cartilage contact pressure and decreased contact area in dysplastic hips as potential causes of early osteoarthritis (e.g., [2]), but have been limited by the use of simplified geometry and the omission of the labrum. The objective of this study was to compare labrum and cartilage mechanics between normal and dysplastic hips using a validated approach to subject-specific finite element modeling of the hip.

Finite Element Predictions of Joint Contact Mechanics and Acetabular Curvature in Dysplastic Human Hips

2013 ◽  
Author(s):  
Corinne R. Henak ◽  
Christine L. Abraham ◽  
Andrew E. Anderson ◽  
Christopher L. Peters ◽  
Steve A. Maas ◽  
...  
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Acetabular Dysplasia ◽  
Hip Osteoarthritis ◽  
Joint Geometry ◽  
Cartilage Mechanics ◽  
Clinical Observations ◽  
Joint Contact ◽  
Dysplastic Hip ◽  
And Cartilage

Acetabular dysplasia is characterized by a shallow acetabulum and is believed to cause accelerated hip osteoarthritis (OA) via altered mechanics (Fig. 1 A, B) [1]. Dysplastic acetabula are also described as more flat and less congruent than normal acetabula [2]. However, the relative contributions of altered labrum and cartilage contact mechanics, as well as quantitative differences in curvature are poorly understood in the dysplastic hip compared to the normal hip. Clinical observations of hypertrophied and damaged labra indicate altered labrum mechanics in dysplastic hips [3]. Finite element (FE) studies demonstrate abnormal cartilage mechanics in dysplastic hips, but are limited to models that omit the labrum or utilize idealized joint geometry (e.g., [4]). Therefore, the objectives of this study were to compare contact mechanics and curvature between normal and dysplastic hips using subject-specific FE models.

Dynamic contact stress and frictional heat analysis of femoral head-on-acetabular cup interface based on calculation and simulation methods

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xingxing Fang ◽  
Dahan Li ◽  
Yucheng Xin ◽  
Songquan Wang ◽  
Yongbo Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Contact Stress ◽  
Contact Area ◽  
Gait Cycle ◽  
Dynamic Change ◽  
Dynamic Contact ◽  
Frictional Heat ◽  
Acetabular Cup ◽  
Content Type

Purpose The purpose of this paper is to systematically study the dynamic contact stress, frictional heat and temperature field of femoral head-on-acetabular cup contact pairs in a gait cycle. Design/methodology/approach In this paper, four common femoral head-on-acetabular cup contact pairs are used as the research objects, mathematical calculations and finite element simulations are adopted. The contact model of hip joint head and acetabular cup was established by finite element simulation to analyze the stress and temperature distribution of the contact interface. Findings The results show that the contact stress of the head-on-cup interface is inversely proportional to the contact area; high contact stress directly leads to greater frictional heat. However, hip joints with metal-on-polyethylene or ceramic-on-polyethylene paired interfaces have lower frictional heat and show a significant temperature rise in one gait cycle, which may be related to the material properties of the acetabular cup. Originality/value Previous studies about calculating the interface frictional heat always ignore the dynamic change process in the contact load and the contact area. This study considered the dynamic changes of the contact stress and area of the femoral head-on-acetabular cup interface, and four common contact pairs were systematically analyzed.

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.

Nonanatomic Placement of Posteromedial Meniscal Root Repairs: A Finite Element Study

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Brett D. Steineman ◽  
Robert F. LaPrade ◽  
Tammy L. Haut Donahue
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Contact Area ◽  
Hoop Stress ◽  
Meniscal Extrusion ◽  
Meniscal Root ◽  
Knee Mechanics ◽  
Total Contact Area ◽  
And Cartilage ◽  
Element Study

Abstract Nonanatomic placement of posteromedial meniscal root repairs alters knee mechanics; however, little is known about how the position and magnitude of misplacement affect knee mechanics. Finite element knee models were developed to assess changes in cartilage and meniscus mechanics for anatomic and various nonanatomic repairs with respect to intact. In total, 25 different repair locations were assessed at loads of 500 N and 1000 N. The two-simple-suture method was represented within the models to simulate posteromedial meniscal root repairs. Anatomic repairs nearly restored total contact area; however, meniscal hoop stress decreased, meniscal extrusion increased, and cartilage–cartilage contact area increased. Repairs positioned further posterior altered knee mechanics the most and repairs positioned further anterior restored knee mechanics for posteromedial root repairs. Despite this, repair tension increased with further anterior placement. Anterior placement of repairs results in more restorative contact mechanics than posterior placement; however, anterior placement also increased the risk of suture cut-out or failure following repairs. Anatomic placement of repairs remains the best option because of the risks involved with anterior placement; however, suture methods need to be improved to better restore the strength of repairs to that of the native insertion. Proper placement of repairs is important to consider with meniscal root repairs because misplacement may negatively affect cartilage and meniscus mechanics in patients.

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.

Reconstruction of the biomechanical transfer path of femoral head necrosis: A subject-specific finite element investigation

2014 ◽  
Vol 52 ◽  
pp. 96-101 ◽  
Author(s):  
Guang-Quan Zhou ◽  
Zhi-Hui Pang ◽  
Qin-Qun Chen ◽  
Wei He ◽  
Zhen-Qiu Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Femoral Head ◽  
Femoral Head Necrosis ◽  
Transfer Path ◽  
Subject Specific

Computationally Efficient Finite Element Evaluation of Natural Patellofemoral Mechanics

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Clare K. Fitzpatrick ◽  
Mark A. Baldwin ◽  
Paul J. Rullkoetter
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Rigid Body ◽  
Contact Mechanics ◽  
Contact Area ◽  
Probabilistic Methods ◽  
Computationally Efficient ◽  
Subject Specific ◽  
Contact Pressures

Finite element methods have been applied to evaluate in vivo joint behavior, new devices, and surgical techniques but have typically been applied to a small or single subject cohort. Anatomic variability necessitates the use of many subject-specific models or probabilistic methods in order to adequately evaluate a device or procedure for a population. However, a fully deformable finite element model can be computationally expensive, prohibiting large multisubject or probabilistic analyses. The aim of this study was to develop a group of subject-specific models of the patellofemoral joint and evaluate trade-offs in analysis time and accuracy with fully deformable and rigid body articular cartilage representations. Finite element models of eight subjects were used to tune a pressure-overclosure relationship during a simulated deep flexion cycle. Patellofemoral kinematics and contact mechanics were evaluated and compared between a fully deformable and a rigid body analysis. Additional eight subjects were used to determine the validity of the rigid body pressure-overclosure relationship as a subject-independent parameter. There was good agreement in predicted kinematics and contact mechanics between deformable and rigid analyses for both the tuned and test groups. Root mean square differences in kinematics were less than 0.5 deg and 0.2 mm for both groups throughout flexion. Differences in contact area and peak and average contact pressures averaged 5.4%, 9.6%, and 3.8%, respectively, for the tuned group and 6.9%, 13.1%, and 6.4%, respectively, for the test group, with no significant differences between the two groups. There was a 95% reduction in computational time with the rigid body analysis as compared with the deformable analysis. The tuned pressure-overclosure relationship derived from the patellofemoral analysis was also applied to tibiofemoral (TF) articular cartilage in a group of eight subjects. Differences in contact area and peak and average contact pressures averaged 8.3%, 11.2%, and 5.7% between rigid and deformable analyses in the tibiofemoral joint. As statistical, probabilistic, and optimization techniques can require hundreds to thousands of analyses, a viable platform is crucial to component evaluation or clinical applications. The computationally efficient rigid body platform described in this study may be integrated with statistical and probabilistic methods and has potential clinical application in understanding in vivo joint mechanics on a subject-specific or population basis.

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