LUBRICATION PREDICTIONS FOR TOTAL KNEE PROSTHESIS MADE OF HARD MATERIALS

2015 ◽  
Vol 45 (1) ◽  
pp. 45-50
Author(s):  
J. DI PAOLO ◽  
M. E. BERLI
Keyword(s):  
Gait Cycle ◽  
Knee Prosthesis ◽  
Knee Prostheses ◽  
Total Knee Prosthesis ◽  
Hard Materials ◽  
Lubrication Regime ◽  
Total Knee ◽  
Lubricated Contact ◽  
Film Lubrication ◽  
Generalized Reynolds Equation

The lubricated contact zone in a total knee prosthesis is modeled, where femoral and tibial components are supposed to be made of hard materials (high stiffness and hardness) and lubricated by a non Newtonian fluid (synovial liquid). To determine optimal relations among geometric parameters, load and film thickness, a generalized Reynolds equation was solved by means of finite element method. Although mix lubrication regime is predominant, it is shown that increasing conformity, it could be assure a full-film lubrication regime in most of the gait cycle. These results might be a reference to make more durable total knee prostheses.

scholarly journals Comparison of the Clinical Results of Identically Designed Total Knee Prostheses with Different Surface Roughnesses

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 486
Author(s):  
Sang Hyun Ko ◽  
Kyoung Ho Moon
Keyword(s):  
Surface Roughness ◽  
Knee Prosthesis ◽  
Functional Results ◽  
Clinical Results ◽  
Knee Prostheses ◽  
Total Knee Prosthesis ◽  
Significant Evidence ◽  
Average Surface ◽  
Total Knee ◽  
The Difference

The purpose of this study was to investigate the effects of the undersurface roughness of total knee prosthesis on clinical outcomes. We compared the clinical and radiological outcomes and prosthesis survivals in patients who underwent total knee arthroplasty using prosthesis with identical designs but different surface roughness (average surface roughnesses (Ra), 5.0 μm vs. 11.6 μm). The results showed that the knee prostheses with a more roughened undersurface (Ra = 11.6 μm) produced significantly better functional results and enhanced prosthesis survival. The difference in surface roughness was associated with incidence of osteolysis and loosening at the tibial baseplate, but not at the femoral component. Overall, our results provided significant evidence that the use of roughened undersurface of tibial baseplate would be a way to prevent aseptic loosening.

scholarly journals The Influence Of Component Alignment On The Life Of Total Knee Prostheses

2012 ◽  
Vol 56 (1) ◽  
pp. 123-126
Author(s):  
Delia Bugariu ◽  
Liviu Bereteu
Keyword(s):  
Numerical Analysis ◽  
Knee Prosthesis ◽  
Wear Particles ◽  
Knee Prostheses ◽  
Mechanical Behaviors ◽  
Ansys Software ◽  
Total Knee Prosthesis ◽  
Component Alignment ◽  
Total Knee ◽  
Arthritic Knee

AbstractAn arthritic knee affects the patient’s life by causing pain and limiting movement. If the cartilage and the bone surfaces are severely affected, the natural joint is replaced with an artificial joint. The procedure is called total knee arthroplasty (TKA). Lately, the numbers of implanted total knee prostheses grow steadily. An important factor in TKA is the perfect alignment of the total knee prosthesis (TKP) components. Component misalignment can lead to the prosthesis loss by producing wear particles. The paper proposes a study on mechanical behaviors of a TKP based on numerical analysis, using ANSYS software. The numerical analysis is based on both the normal and the changed angle of the components alignment.

Patellofemoral Contact Characteristics in Total Knee Prostheses with and Without Anterior Patellar Flange

2004 ◽  
Vol 20 (2) ◽  
pp. 144-152 ◽  
Author(s):  
Susanne Fuchs ◽  
Guido Schuette ◽  
Hartmut Witte, ◽  
Carsten Oliver Tibesku
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Contact Area ◽  
Knee Prosthesis ◽  
Maximum Pressure ◽  
Knee Prostheses ◽  
Total Knee Prosthesis ◽  
Essential Change ◽  
Before And After ◽  
Total Knee

A new design of total knee prosthesis without anterior patellar flange was developed to preserve the anatomical shape of the patellofemoral joint. The aim of the current study was to experimentally compare patellofemoral contact area and pressure in a nonreplaced knee, in a knee after implantation of a conventionally designed total knee arthroplasty, and in a knee after implantation of the newly designed total knee arthroplasty without patellar flange. Six cadaveric legs were examined before and after implantation of either a conventional or a newly developed total knee arthroplasty, both without patellar replacement. The essential change in design is the absence of an anterior patellar flange. Contact area and pressure were measured using pressure sensitive films in 45°, 60°, 90°, and 120° of flexion and the results were compared between the different prosthesis designs and with the nonreplaced knee. The prosthesis without patellar flange showed less average and maximum pressure than the conventional prosthesis. Compared with the nonreplaced knee, the conventional prosthesis led to increased average and maximum pressure and decreased contact area. In an experimental test setup, the newly developed total knee arthroplasty without patellar flange showed reduced patello-femoral contact pressure in comparison with a total knee prosthesis with conventional patellofemoral design. This could possibly lead to a lower incidence of anterior knee complaints in patients.

How to Define the Contact Point of the Tibiofemoral Joint of the Prosthesis in In-Vitro Biomechanical Testing

1998 ◽  
Vol 02 (03) ◽  
pp. 237-245 ◽  
Author(s):  
Cheng-Kung Cheng ◽  
Jiann-Jong Liau ◽  
Chun-Hsiung Huang ◽  
Ye-Ming Lee ◽  
Shan-Chang Chueh
Keyword(s):  
Knee Prosthesis ◽  
Contact Point ◽  
Biomechanical Testing ◽  
Knee Prostheses ◽  
Total Knee Prosthesis ◽  
Tibiofemoral Joint ◽  
Contact Points ◽  
Total Knee ◽  
Maximum Contact

No standard method has been provided to define the contact point of the tibiofemoral joint of the total knee prosthesis. Our objective was to estimate the contact point of the tibiofemoral joint in in vitro biomechanical testing of the total knee prosthesis. Three commercial knee prostheses were used for testing. We applied compression loads and used Fuji-prescale films to measure the contact areas at different flexion angles (0°, 10°, 30°, and 60°). The contact point was calculated when the maximum contact configuration was achieved. We used a sensitivity analysis and digital image analysis of the Fuji-prescale film to find the contact point at different flexion angles. From the results, we found that the contact points of the 3 prostheses were all approximately at 30%–60% of the depth of the tibial plateau dimension relative to the posterior edge and symmetrically relative to the midline of the mediolaterial width. All three prostheses had the same tendency in which the contact point first moved anteriorly during 0° to 10° flexion, and then moved more posteriorly after 10° flexion. The present method using the maximum contact area to estimate the contact point for different flexion angles, should be applicable for in vitro biomechanical evaluation of the total knee prosthesis.

scholarly journals Analysis of Friction in Total Knee Prosthesis during a Standard Gait Cycle

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 36
Author(s):  
Matúš Ranuša ◽  
Markus A. Wimmer ◽  
Spencer Fullam ◽  
Martin Vrbka ◽  
Ivan Křupka
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Computational Models ◽  
Gait Cycle ◽  
Knee Prosthesis ◽  
Shear Stresses ◽  
Cobalt Chromium ◽  
Joint Friction ◽  
The Coefficient Of Friction ◽  
Total Knee

Total knee arthroplasty is on the rise worldwide. Despite its success, revision surgeries are also increasing. According to the American Joint Replacement Registry 2020, 3.3% of revision surgeries are due to wear, and 24.2% are due to mechanical loosening. The combination of shear stresses and wear particles occurring at the bone/implant interface can lead to local osteolysis. Although the shear stresses are partially driven by joint friction, relatively little is known about the evolution of the coefficient of friction (CoF) during a gait cycle in total knee replacement. Here we describe the CoF during a gait cycle and investigate its association with kinematics (slide–roll-ratio), applied load, and relative velocity. The artificial knee was simulated by cobalt–chromium condyle on a flat ultra-high-molecular-weight polyethylene (UHMWPE) tibial plateau, lubricated by either water or proteinaceous solution. We found that the CoF is not a constant but fluctuates between the values close to 0 and 0.15. Cross-correlation suggested that this is primarily an effect of the slide–roll ratio and the contact pressure. There was no difference in the CoF between water and proteinaceous solution. Knowledge about the CoF behavior during a gait cycle will help to increase the accuracy of future computational models of total knee replacement.

On the true wear rate of ultrahigh molecular weight polyethylene in the total knee prosthesis

1984 ◽  
Vol 18 (2) ◽  
pp. 207-224 ◽  
Author(s):  
Robert M. Rose ◽  
Michael D. Ries ◽  
Igor L. Paul ◽  
Aldo M. Crugnola ◽  
Edward Ellis
Keyword(s):  
Molecular Weight ◽  
Wear Rate ◽  
Knee Prosthesis ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Total Knee Prosthesis ◽  
Ultrahigh Molecular Weight ◽  
Total Knee
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