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The effect of surface modification of acetabular cup on friction coefficient of hip implant
Cahová, Aneta ; Valena, Martin (referee) ; Nečas, David (advisor)
This bachelor’s thesis is focused on limited longevity of hip joint replacements. In order to extend the longevity of replacements effect of microtexture application on surface of artificial acetabulum cup on coefficient of friction was investigated. Attention was paid to composition of model synovial fluid and geometry and layout of texture. For joint simulation, a pendulum hip joint simulator was employed. In first part three femoral heads, two acetabulum cups and five fluids were tested, respectively two heads, four acetabulum cups and one fluid in second part. Significant effect of fluid composition and geometry and layout of texture was observed during measurement. Compared smooth and textured cup the highest decline of friction was 78 %. Results can be used for further research of micortextures. Friction reduction and prolonging lifespan of implants may eventually improve life quality of many patients.
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Friction analysis of hip joint replacements with coated surface
Nosek, Matěj ; Streďanská, Alexandra (referee) ; Nečas, David (advisor)
This bachelor thesis focuses on the effect that results from applying a coating to hip joint replacement based on the friction coefficient. The aim of this thesis was to conclude a comparison between individual combinations with and without coating in three types of fluids. Experimental measurements were conducted in configuration ball-on-head in a pendulum hip joint simulator. For these measurements, DEWEsoft, MATLAB, and MS Excel were used. During the measurements, four balls, two cups, and three fluids were used. The coating is a polymer-based solution made out of PEGMA-360 a PEGDMA-550. With the usage of the coating, gathered results point out that the coefficient of friction declines by a maximum of 5,4 % and increases by a maximum of 16,1 % compared to those without any coating. Results presented by this thesis may be in the service of further research of coatings and their application on hip joint replacement, which might increase the potency of those implants.
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An investigation of friction and lubrication of coated hip joint replacement
Balcárek, Ondřej ; Horák, Zdeněk (referee) ; Nečas, David (advisor)
The thesis focused on studying the effects of a new hydrogel coating and material combinations on the coefficient of friction and formation of lubricating film in the conformal contact of hip joint replacement. Experiments were conducted using a ball-on-cup configuration with a hip pendulum simulator. The formation of the lubricating film was observed using fluorescence microscopy. The results showed that the application of the coating did not have a clear impact on the coefficient of friction. However, for pairs with a coated cup, there was a reduction in CoF by approximately 20%. Generally, lower friction was observed when using a ceramic joint head. Surprisingly, even more interesting results were obtained in the lubrication analysis, where the use of metal heads led to a reduction in the thickness of the lubricating layer. Ceramic pairs exhibited very stable behavior. In addition to friction and lubrication, the topography of the implants was further evaluated, and their wettability was analysed. Although the polymer coating was expected to be highly hydrophilic, the surface properties were only slightly influenced, which partly explains why there was no significant improvement in the tribological behavior of the replacement. As the coating applied is already patented and its effectiveness in reducing wear has been clearly demonstrated, it is appropriate to investigate this issue further, with more attention being paid to long-term experiments. Based on the obtained data, it appears that the short-term benefits of the coating are practically negligible. However, it is important to highlight that, except for minor exceptions, the application of the coating did not lead to a deterioration of properties, which is a significant outcome of this work.
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Friction analysis of hip joint replacements with coated surface
Nosek, Matěj ; Streďanská, Alexandra (referee) ; Nečas, David (advisor)
This bachelor thesis focuses on the effect that results from applying a coating to hip joint replacement based on the friction coefficient. The aim of this thesis was to conclude a comparison between individual combinations with and without coating in three types of fluids. Experimental measurements were conducted in configuration ball-on-head in a pendulum hip joint simulator. For these measurements, DEWEsoft, MATLAB, and MS Excel were used. During the measurements, four balls, two cups, and three fluids were used. The coating is a polymer-based solution made out of PEGMA-360 a PEGDMA-550. With the usage of the coating, gathered results point out that the coefficient of friction declines by a maximum of 5,4 % and increases by a maximum of 16,1 % compared to those without any coating. Results presented by this thesis may be in the service of further research of coatings and their application on hip joint replacement, which might increase the potency of those implants.
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The influence of the quality of articulation UHMWPE inserts on the lifetime of joint replacements
Fulín, Petr ; Pokorný, David (advisor) ; Koudela, Karel (referee) ; Gallo, Jiří (referee)
This thesis focuses on the introduction with the problems of high molecular weight polyethylene (UHMWPE) in orthopedics in the first part. It discusses the history, properties and processes that lead to the failure of UHMWPE joint replacement components. The experimental part validates the hypotheses expressed. It acquaints readers with the experimental verification of the effect of different types of sterilization on the oxidative stability of laboratory prepared samples and explanted UHMWPE joint replacement components using methods of infrared microscopy, electron spin resonance, mechanical tests and tests of microhardness. Other experimental measurements on a large set of explanted components of hip and knee total joint replacements validates the hypothesis that the amount of oxidative damage affects the lifespan of joint replacements. The third part of the experimental study maps the degree of oxidative damage in different places of the hip and knee joint replacements. In the final part we experimentally demonstrate the fact that the rate of oxidative damage has an effect on supramolecular structure of the UHMWPE. From the above experiments are concluded clearly defined recommendations for clinical practice, which should lead to extend the lifespan of total joints replacements in orthopaedics....
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The effect of surface modification of acetabular cup on friction coefficient of hip implant
Cahová, Aneta ; Valena, Martin (referee) ; Nečas, David (advisor)
This bachelor’s thesis is focused on limited longevity of hip joint replacements. In order to extend the longevity of replacements effect of microtexture application on surface of artificial acetabulum cup on coefficient of friction was investigated. Attention was paid to composition of model synovial fluid and geometry and layout of texture. For joint simulation, a pendulum hip joint simulator was employed. In first part three femoral heads, two acetabulum cups and five fluids were tested, respectively two heads, four acetabulum cups and one fluid in second part. Significant effect of fluid composition and geometry and layout of texture was observed during measurement. Compared smooth and textured cup the highest decline of friction was 78 %. Results can be used for further research of micortextures. Friction reduction and prolonging lifespan of implants may eventually improve life quality of many patients.
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The influence of the quality of articulation UHMWPE inserts on the lifetime of joint replacements
Fulín, Petr ; Pokorný, David (advisor) ; Koudela, Karel (referee) ; Gallo, Jiří (referee)
This thesis focuses on the introduction with the problems of high molecular weight polyethylene (UHMWPE) in orthopedics in the first part. It discusses the history, properties and processes that lead to the failure of UHMWPE joint replacement components. The experimental part validates the hypotheses expressed. It acquaints readers with the experimental verification of the effect of different types of sterilization on the oxidative stability of laboratory prepared samples and explanted UHMWPE joint replacement components using methods of infrared microscopy, electron spin resonance, mechanical tests and tests of microhardness. Other experimental measurements on a large set of explanted components of hip and knee total joint replacements validates the hypothesis that the amount of oxidative damage affects the lifespan of joint replacements. The third part of the experimental study maps the degree of oxidative damage in different places of the hip and knee joint replacements. In the final part we experimentally demonstrate the fact that the rate of oxidative damage has an effect on supramolecular structure of the UHMWPE. From the above experiments are concluded clearly defined recommendations for clinical practice, which should lead to extend the lifespan of total joints replacements in orthopaedics....
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