IN-VIVOESTIMATION OF THE TIBIO-FEMORAL CONTACT AREA USING THIN-PLATE SPLINE TOOL

2010 ◽  
Vol 10 (02) ◽  
pp. 237-249
Author(s):  
LUIGI BERTOZZI ◽  
RITA STAGNI ◽  
SILVIA FANTOZZI ◽  
ANGELO CAPPELLO
Keyword(s):  
Knee Joint ◽  
Thin Plate ◽  
Contact Area ◽  
Specific Model ◽  
Clinical Tool ◽  
Physiological Conditions ◽  
Clinical Procedures ◽  
Articular Surfaces ◽  
Analytical Estimation ◽  
Good Repeatability

Interaction between articular surfaces at the knee joint allows movement and stability. The knowledge of how this mechanism works in physiological conditions could be very useful for the development of new clinical procedures. The objective of this study was to develop a subject-specific model able to estimate the articular contact area at the tibio-femoral joint avoiding any destructive measurements. Thin plate splines were used to describe articular surfaces and to allow an analytical estimation of the distance between the surfaces. The sensitivity of the model was evaluated and the tibio-femoral contact area was estimated in a living subject. Femoral contact area results were always smaller than the tibial one, whereas tibial contact area results were less repeatable. Increasing the distance threshold, the increase of the contact area was almost linear. High repeatability was obtained sampling each condyle with more than 60 steps. Contact areas, estimated with the loaded knee, were in accordance with physiology and literature showing a good repeatability. The devised model was suitably used to evaluate the articular contact at the knee joint of an healthy living subject and can be a useful clinical tool to suggest procedures aimed at restoring physiological conditions.

Load-Bearing in the Ovine Medial Tibial Condyle: Effect of Meniscectomy

1993 ◽  
Vol 06 (02) ◽  
pp. 100-104 ◽  
Author(s):  
D. M. Pickles ◽  
C. R. Bellenger
Keyword(s):  
Knee Joint ◽  
Contact Area ◽  
Mammalian Species ◽  
Total Removal ◽  
Load Bearing ◽  
Human Knee ◽  
Biochemical Effects ◽  
Pressure Sensitive ◽  
Medial Meniscectomy ◽  
Tibial Condyle

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.

scholarly journals 1. On the Mechanism of the Knee Joint

1862 ◽  
Vol 4 ◽  
pp. 67-73 ◽  
Author(s):  
Goodsir
Keyword(s):  
Knee Joint ◽  
Articular Surfaces

After alluding to the comparatively superficial manner in which physiologists, with the exception of the brothers Weber, have hither-to investigated the structure and movements of the joints, the author gave an abstract of the general results which he had formerly obtained in an examination of the knee-joint, made with reference to Meyer's valuable observations. He had found that, as stated by Meyer, the thigh and leg rotate on one another in opposite directions,—at the close of extension, and at the commencement of flexion; and that the co-ordinated movements in the patella, the ligaments, and muscles correspond generally with the account given by that observer; but in addition he had ascertained what had previously escaped notice,1. That the articular surfaces of the femur, tibia, and patella are not continuous but faceted surfaces.

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.

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.

MEASUREMENT AND FITTING ON 3-D ARTICULAR SURFACES OF THE HUMAN KNEE JOINT

2002 ◽  
Vol 14 (04) ◽  
pp. 171-174
Author(s):  
XISHI WANG ◽  
LI-QUN ZHANG
Keyword(s):  
Knee Joint ◽  
Three Dimensional ◽  
Reconstruction Error ◽  
Reconstruction Procedure ◽  
Human Knee ◽  
Articular Surfaces ◽  
Human Knee Joint ◽  
Surface Measurements ◽  
Articulating Surface ◽  
Relative Analysis

In this study, the OptoTrak system was employed to collect the articulating surface measurements of the human knee for the femur, tibia and patella in three experimented specimens. Furthermore, a rigorous mathematical reconstruction procedure that estimates reconstruction error was completed by employed the relative analysis tools. The results show, the measurements for each session were able to reconstruct the three-dimensional calibration to a precision of 0.02mm. On the other word, the OptoTrak can be used to obtain the precise measurements of analytical surface of the human knee joint.

scholarly journals FRACTURES OF THE ARTICULAR SURFACES OF THE KNEE-JOINT

BMJ ◽  
1930 ◽  
Vol 2 (3637) ◽  
pp. 466-468
Author(s):  
R. Ollerenshaw
Keyword(s):  
Knee Joint ◽  
Articular Surfaces

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.

scholarly journals Visual assessment of dynamic knee joint alignment in patients with patellofemoral pain: an agreement study

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12203
Author(s):  
Rudi Hansen ◽  
Mathilde Lundgaard-Nielsen ◽  
Marius Henriksen
Keyword(s):  
Knee Joint ◽  
Video Recording ◽  
Visual Assessment ◽  
Patellofemoral Pain ◽  
Interrater Agreement ◽  
Kappa Statistics ◽  
Clinical Tool ◽  
Easy Method ◽  
Cross Sectional ◽  
Agreement Study

Background Assessment of knee kinematics plays an important role in the clinical examination of patients with patellofemoral pain (PFP). There is evidence that visual assessments are reliable in healthy subjects, but there is a lack of evidence in injured populations. The purpose of this study was to examine the intra- and interrater agreement in the visual assessment of dynamic knee joint alignment in patients with PFP. Methods The study was a cross-sectional agreement study. Sixty participants (42 females) were included. We assessed the intra- and interrater agreement of two functional tests: The single leg squat (SLS) and the forward lunge (FL). One investigator scored the movement according to preset criteria while video recording the movement for retest. Moreover, the performance was scored by another investigator using the video recording. Agreement was assessed using weighted kappa statistics. Results The intrarater agreement ranged from moderate to good (Kappa 0.58 (FL) to 0.70 (SLS)) whereas the interrater agreement ranged from fair to moderate (Kappa 0.22 (SLS) to 0.50 (FL)). Conclusion The agreement within raters was better than between raters, which suggests that assessments should preferably be performed by the same tester in research and in a clinical setting, e.g., to evaluate any treatment effect. We promote FL as a reliable clinical tool for evaluating dynamic knee alignment, since it shows equally good intra- and interrater agreement, and it is an inexpensive and easy method to use.

A Novel Quantitative Approach for Evaluating Contact Mechanics of Meniscal Replacements

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
E. Linder-Ganz ◽  
J. J. Elsner ◽  
A. Danino ◽  
F. Guilak ◽  
A. Shterling
Keyword(s):  
Contact Area ◽  
Peak Pressure ◽  
Contact Forces ◽  
Articular Surfaces ◽  
Joint Contact ◽  
Bench Testing ◽  
Contact Pressures ◽  
Implant Dislocation ◽  
Total Contact Area

One of the functions of the meniscus is to distribute contact forces over the articular surfaces by increasing the joint contact areas. It is widely accepted that total/partial loss of the meniscus increases the risk of joint degeneration. A short-term method for evaluating whether degenerative arthritis can be prevented or not would be to determine if the peak pressure and contact area coverage of the tibial plateau (TP) in the knee are restored at the time of implantation. Although several published studies already utilized TP contact pressure measurements as an indicator for biomechanical performance of allograft menisci, there is a paucity of a quantitative method for evaluation of these parameters in situ with a single effective parameter. In the present study, we developed such a method and used it to assess the load distribution ability of various meniscal implant configurations in human cadaveric knees (n=3). Contact pressures under the intact meniscus were measured under compression (1200 N, 0 deg flexion). Next, total meniscectomy was performed and the protocol was repeated with meniscal implants. Resultant pressure maps were evaluated for the peak pressure value, total contact area, and its distribution pattern, all with respect to the natural meniscus output. Two other measures—implant-dislocation and implant-impingement on the ligaments—were also considered. If any of these occurred, the score was zeroed. The total implant score was based on an adjusted calculation of the aforementioned measures, where the natural meniscus score was always 100. Laboratory experiments demonstrated a good correlation between qualitative and quantitative evaluations of the same pressure map outputs, especially in cases where there were contradicting indications between different parameters. Overall, the proposed approach provides a novel, validated method for quantitative assessment of the biomechanical performance of meniscal implants, which can be used in various applications ranging from bench testing of design (geometry and material of an implant) to correct implant sizing.

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