STUDY ON MECHANICAL PROPERTIES OF TOTAL KNEE ARTICULAR CARTILAGE UNDER DIFFERENT LOADING RATES

2019 ◽  
Vol 19 (04) ◽  
pp. 1950016
Author(s):  
SHILEI WANG ◽  
LILAN GAO ◽  
CHUNQIU ZHANG ◽  
YANG SONG ◽  
XIZHENG ZHANG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Knee Joint ◽  
Contact Pressure ◽  
Contact Area ◽  
Weight Bearing ◽  
Joint Cartilage ◽  
Main Bearing ◽  
Loading Rates ◽  
Intact Cartilage ◽  
Peak Contact Pressure

Knee joint is the main weight bearing tissue of human body, also it is one of the prone parts of the clinical disease. Under different sports conditions, knee joint was loaded at different forms. In this study, the changes of average contact pressure, peak contact pressure, contact area and pressure-sharing regions were researched using the intact and defect pig knee joints under different loading rates and loads, including fast rates and large loads. These data were measured and recorded by usage of the sensor plate that placed between the unilateral meniscus and the femur cartilage during loading process. As for the intact cartilage samples, the average contact pressure and peak contact pressure of the femur cartilage increase with the loading rate, while the contact area is contrast to it. As for defect cartilage samples, it not only emerged stress concentration on the edge of the defect and pressure distribution in joint cavity was different with intact cartilage samples, but also the main bearing region was transferred from the femur cartilage-meniscus contact area to the femur cartilage-tibial cartilage contact area at different loading forms. In different loading stages, the pressure-sharing regions between the cartilage and the meniscus also changes. Different loading rates, different loads and defects will change the mechanical states of the knee joint. In loading forms, the mechanical condition may cause or aggravate damnification of the knee joint cartilage. Therefore, this study is beneficial for promoting and perfecting the research of mechanical properties of knee joint cartilage and provides a theoretical basis for the prevention and treatment of knee cartilage injury.

Experimental and Theoretical Study of the Contact Mechanics of Five Total Knee Joint Replacements

1995 ◽  
Vol 209 (4) ◽  
pp. 225-231 ◽  
Author(s):  
T Stewart ◽  
Z M Jin ◽  
D Shaw ◽  
D D Auger ◽  
M Stone ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Knee Joint ◽  
Contact Pressure ◽  
Contact Stress ◽  
Linear Elasticity ◽  
Contact Area ◽  
Elasticity Analysis ◽  
Joint Replacements ◽  
Total Knee ◽  
Maximum Contact

The tibio-femoral contact area in five current popular total knee joint replacements has been measured using pressure-sensitive film under a normal load of 2.5 kN and at several angles of flexion The corresponding maximum contact pressure has been estimated from the measured contact areas and found to exceed the point at which plastic deformation is expected in the ultra-high molecular weight polyethylene (UHMWPE) component particularly at flexion angles near 90°. The measured contact area and the estimated maximum contact stress have been found to be similar in magnitude for all of the five knee joint replacements tested. A significant difference, however, has been found in maximum contact pressure predicted from linear elasticity analysis for the different knee joints. This indicates that varying amounts of plastic deformation occurred in the polyethylene component in the different knee designs. It is important to know the extent of damage as knees with large amounts of plastic deformation are more likely to suffer low cycle fatigue failure. It is therefore concluded that the measurement of contact areas alone can be misleading in the design of and deformation in total knee joint replacements. It is important to modify geometries to reduce the maximum contact stress as predicted from the linear elasticity analysis, to below the linear elastic limit of the plastic component.

Contact Pressure Prediction in Total Knee Joint Replacements Part 1: General Elasticity Solution for Elliptical Layered Contacts

1995 ◽  
Vol 209 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Z M Jin ◽  
D Dowson ◽  
J Fisher
Keyword(s):  
Knee Joint ◽  
Contact Pressure ◽  
Contact Area ◽  
Contact Theory ◽  
Joint Replacements ◽  
Interfacial Boundary ◽  
Total Knee ◽  
Typical Design ◽  
Maximum Contact ◽  
Ultra High Molecular Weight

A general elasticity contact theory has been developed, to predict the contact area and the contact pressure in total knee joint replacements with elliptical contacts where the thickness of ultra high molecular weight polyethylene (UHMWPE) is similar or less than the contact half width. The interfacial boundary condition between the UHMWPE component and the underlying metal substrate has been considered to be either perfectly bonded or perfectly unbonded in the model. Poisson's ratio for UHMWPE has been assumed to be 0.3 or 0.4. The effect of the thickness of the UHMWPE layer on the contact area and the contact pressure has been examined. The predictions of the maximum contact pressure and the contact area have been presented in non-dimensional forms and can readily be applied for typical design configurations of current total knee joint replacements. Furthermore, the present results can readily be applied to design considerations for total knee joint replacements to reduce contact stresses within the UHMWPE component.

The effect of routine hoof trimming on midstance regional hoof kinetics at walk

2019 ◽  
Vol 15 (3) ◽  
pp. 167-171
Author(s):  
B. Faramarzi ◽  
F. Hung ◽  
A. Nguyen ◽  
F. Dong
Keyword(s):  
Contact Pressure ◽  
Contact Area ◽  
Evidence Based ◽  
Pressure Plate ◽  
Before And After ◽  
Peak Contact Pressure ◽  
The Impact ◽  
Quality Evidence

There is a lack of objective and quality evidence-based research on the effect of trimming on hoof loading at different regions of the hoof. Our objective was to measure and compare force (F), contact area (CA), contact pressure (CP) and peak contact pressure (PCP) of the dorsal vs palmar and medial vs lateral regions of the forehooves. Nine sound equine athletes were walked across a calibrated pressure plate before and after routine hoof trimming. The F, CA, CP and PCP in medial, lateral, dorsal and palmar regions were examined pre- and post-trimming, P≤0.05 was considered significant. Dorsal CP and PCP significantly increased post-trimming (P=0.039 and P=0.019, respectively). Medial F increased about 25% after trimming, but not significantly (P=0.129). These data confirm the impact of individual hoof trimming on certain aspects of the hoof midstance biomechanics.

Repair of Lateral Meniscus Posterior Horn Detachment Lesions

2012 ◽  
Vol 40 (11) ◽  
pp. 2604-2609 ◽  
Author(s):  
Carl K. Schillhammer ◽  
Frederick W. Werner ◽  
Matthew G. Scuderi ◽  
John P. Cannizzaro
Keyword(s):  
Acl Reconstruction ◽  
Contact Pressure ◽  
Contact Area ◽  
Lateral Meniscus ◽  
Posterior Horn ◽  
Normal Contact ◽  
Intact State ◽  
Peak Contact Pressure ◽  
Maximum Contact ◽  
Contact Pressures

Background: Posterior horn detachment (PHD) lesions of the lateral meniscus are commonly associated with acute anterior cruciate ligament (ACL) tears. Multiple surgeons have advocated for repair of this lesion at the time of ACL reconstruction. However, the biomechanical consequences of this lesion and its subsequent repair have not been evaluated. Hypothesis: The PHD lesion of the lateral meniscus will lead to increased tibiofemoral contact pressures, and repair of this lesion to bone via a tibial tunnel can restore normal contact pressures during simulated gait. Study Design: Controlled laboratory study. Methods: Lateral compartment contact pressures were measured via a sensor on the tibial plateau in 8 cadaver knees with the knee intact, after sectioning the posterior horn of the lateral meniscus to simulate PHD, and after repairing the injury. The repair was performed using an ACL tunnel guide to drill a tunnel from the anteromedial tibia to the posterior horn attachment site. Dynamic pressure data were continuously collected using a conductive ink pressure sensing system while each knee was moved through a physiological gait flexion cycle. Results: Posterior horn detachment caused a significant increase in tibiofemoral peak contact pressure from 2.8 MPa to 4.2 MPa ( P = .03). After repair of the lesion to bone was performed through a transtibial tunnel, the peak contact pressure was 2.9 MPa. Posterior horn detachment also significantly decreased the maximum contact area over which tibiofemoral pressure is distributed from 451 mm2 in the intact state to 304 mm2 in the detached state. Repair of the PHD lesion increased the maximum contact area to 386 mm2, however, this area was also significantly less than in the intact state ( P = .05). Conclusion: Posterior horn detachment of the lateral meniscus causes increased peak tibiofemoral contact pressure. The peak pressure can be reduced to a normal level with repair of the lesion to bone via a transtibial tunnel. Clinical Relevance: Posterior horn detachment of the lateral meniscus is a lesion often associated with an acute ACL tear. Debate exists concerning the importance of repairing PHD lesions at the time of ACL reconstruction. The data provided in this study may influence surgeons’ management of the lesion.

Tensile properties of human knee joint cartilage: I. Influence of ionic conditions, weight bearing, and fibrillation on the tensile modulus

1986 ◽  
Vol 4 (4) ◽  
pp. 379-392 ◽  
Author(s):  
Shaw Akizuki ◽  
Van C. Mow ◽  
Francisco Müller ◽  
Julio C. Pita ◽  
David S. Howell ◽  
...  
Keyword(s):  
Knee Joint ◽  
Tensile Properties ◽  
Weight Bearing ◽  
Tensile Modulus ◽  
Joint Cartilage ◽  
Human Knee ◽  
Human Knee Joint

scholarly journals MRI-Based Modeling for Radiocarpal Joint Mechanics: Validation Criteria and Results for Four Specimen-Specific Models

2011 ◽  
Vol 133 (10) ◽  
Author(s):  
Kenneth J. Fischer ◽  
Joshua E. Johnson ◽  
Alexander J. Waller ◽  
Terence E. McIff ◽  
E. Bruce Toby ◽  
...  
Keyword(s):  
Experimental Data ◽  
Contact Pressure ◽  
Outcome Measures ◽  
Contact Force ◽  
Contact Area ◽  
Peak Pressure ◽  
Experimental Measurements ◽  
Model Data ◽  
Validation Criteria ◽  
Peak Contact Pressure

The objective of this study was to validate the MRI-based joint contact modeling methodology in the radiocarpal joints by comparison of model results with invasive specimen-specific radiocarpal contact measurements from four cadaver experiments. We used a single validation criterion for multiple outcome measures to characterize the utility and overall validity of the modeling approach. For each experiment, a Pressurex film and a Tekscan sensor were sequentially placed into the radiocarpal joints during simulated grasp. Computer models were constructed based on MRI visualization of the cadaver specimens without load. Images were also acquired during the loaded configuration used with the direct experimental measurements. Geometric surface models of the radius, scaphoid and lunate (including cartilage) were constructed from the images acquired without the load. The carpal bone motions from the unloaded state to the loaded state were determined using a series of 3D image registrations. Cartilage thickness was assumed uniform at 1.0 mm with an effective compressive modulus of 4 MPa. Validation was based on experimental versus model contact area, contact force, average contact pressure and peak contact pressure for the radioscaphoid and radiolunate articulations. Contact area was also measured directly from images acquired under load and compared to the experimental and model data. Qualitatively, there was good correspondence between the MRI-based model data and experimental data, with consistent relative size, shape and location of radioscaphoid and radiolunate contact regions. Quantitative data from the model generally compared well with the experimental data for all specimens. Contact area from the MRI-based model was very similar to the contact area measured directly from the images. For all outcome measures except average and peak pressures, at least two specimen models met the validation criteria with respect to experimental measurements for both articulations. Only the model for one specimen met the validation criteria for average and peak pressure of both articulations; however the experimental measures for peak pressure also exhibited high variability. MRI-based modeling can reliably be used for evaluating the contact area and contact force with similar confidence as in currently available experimental techniques. Average contact pressure, and peak contact pressure were more variable from all measurement techniques, and these measures from MRI-based modeling should be used with some caution.

Biomechanical Comparison of Vertical Mattress and Cross-stitch Suture Techniques and Single- and Double-Row Configurations for the Treatment of Bucket-Handle Medial Meniscal Tears

2019 ◽  
Vol 47 (5) ◽  
pp. 1194-1202 ◽  
Author(s):  
Gilberto Y. Nakama ◽  
Camilla C. Kaleka ◽  
Carlos E. Franciozi ◽  
Diego C. Astur ◽  
Pedro Debieux ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Contact Area ◽  
Suture Techniques ◽  
Double Row ◽  
Single Row ◽  
Intact State ◽  
Peak Contact Pressure ◽  
Vertical Mattress ◽  
The Cross ◽  
Bucket Handle

Background: Given the variety of suturing techniques for bucket-handle meniscal repair, it is important to assess which suturing technique best restores native biomechanics. Purpose/Hypothesis: To biomechanically compare vertical mattress and cross-stitch suture techniques, in single- and double-row configurations, in their ability to restore native knee kinematics in a bucket-handle medial meniscal tear model. The hypothesis was that there would be no difference between the vertical mattress and cross-stitch double-row suture techniques but that the double-row technique would provide significantly improved biomechanical parameters versus the single-row technique. Study Design: Controlled laboratory study. Methods: Ten matched pairs of human cadaver knees were randomly assigned to the vertical mattress (n = 10) or cross-stitch (n = 10) repair group. Each knee underwent 4 consecutive testing conditions: (1) intact, (2) displaced bucket-handle tear, (3) single-row suture configuration on the femoral meniscus surface, and (4) double-row suture configuration (repair of femoral and tibial meniscus surfaces). Knees were loaded with a 1000-N axial compressive force at 0°, 30°, 60°, 90°, and 120° of flexion for each condition. Resultant medial compartment contact area, average contact pressure, and peak contact pressure data were recorded. Results: Intact state contact area was not restored at 0° ( P = .027) for the vertical double-row configuration and at 0° ( P = .032), 60° ( P < .001), and 90° ( P = .007) of flexion for the cross-stitch double-row configuration. No significant differences were found in the average contact pressure and peak contact pressure between the intact state and the vertical mattress and cross-stitch repairs with single- and double-row configurations at any flexion angles. When the vertical and cross-stich repairs were compared across all flexion angles, no significant differences were observed in single-row configurations, but in double-row configurations, cross-stitch repair resulted in a significantly decreased contact area, average contact pressure, and peak contact pressure (all P < .001). Conclusion: Single- and double-row configurations of the vertical mattress and cross-stitch inside-out meniscal repair techniques restored native tibiofemoral pressure after a medial meniscal bucket-handle tear at all assessed knee flexion angles. Despite decreased contact area with a double-row configuration, mainly related to the cross-stitch repair, in comparison with the intact state, the cross-stitch double-row repair led to decreased pressure as compared with the vertical double-row repair. These findings are applicable only at the time of the surgery, as the biological effects of healing were not considered. Clinical Relevance: Medial meniscal bucket-handle tears may be repaired with the single- or double-row configuration of vertical mattress or cross-stitch sutures.

scholarly journals Direct Validation of Human Knee-Joint Contact Mechanics Derived From Subject-Specific Finite-Element Models of the Tibiofemoral and Patellofemoral Joints

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Wei Gu ◽  
Marcus G. Pandy
Keyword(s):  
Finite Element ◽  
Knee Joint ◽  
Contact Mechanics ◽  
Contact Pressure ◽  
Weight Bearing ◽  
Human Knee ◽  
Human Knee Joint ◽  
Joint Contact ◽  
Joint Contact Pressure

Abstract The primary aim of this study was to validate predictions of human knee-joint contact mechanics (specifically, contact pressure, contact area, and contact force) derived from finite-element models of the tibiofemoral and patellofemoral joints against corresponding measurements obtained in vitro during simulated weight-bearing activity. A secondary aim was to perform sensitivity analyses of the model calculations to identify those parameters that most significantly affect model predictions of joint contact pressure, area, and force. Joint pressures in the medial and lateral compartments of the tibiofemoral and patellofemoral joints were measured in vitro during two simulated weight-bearing activities: stair descent and squatting. Model-predicted joint contact pressure distribution maps were consistent with those obtained from experiment. Normalized root-mean-square errors between the measured and calculated contact variables were on the order of 15%. Pearson correlations between the time histories of model-predicted and measured contact variables were generally above 0.8. Mean errors in the calculated center-of-pressure locations were 3.1 mm for the tibiofemoral joint and 2.1 mm for the patellofemoral joint. Model predictions of joint contact mechanics were most sensitive to changes in the material properties and geometry of the meniscus and cartilage, particularly estimates of peak contact pressure. The validated finite element modeling framework offers a useful tool for noninvasive determination of knee-joint contact mechanics during dynamic activity under physiological loading conditions.

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