Articles de revues : « Artificial Joint Wear Simulator »

1

Takadama, Hiroaki, et Mineo Mizuno. « A Simulated Synovial Fluid for Wear Characterization of Artificial Hip Joints by a Hip Joint Simulator ». Key Engineering Materials 309-311 (mai 2006) : 1273–76. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.1273.

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The calf serum solution was defined as the international standard lubricant for wear characterization of artificial hip joints. It is, however, known that its composition varies according to age, manufacturing processes or production areas of bovine cattle, and that the difference in composition has large effect on the wear characterization. It was difficult to compare the results obtained by different laboratories. Therefore, it is desirable to develop an artificial lubricant whose composition can be always set to a specified value as an alternative to bovine serum. In the present study, the effect of each major constituent in bovine serum on wear property was studied by hip simulator. As a result, transparent and stable lubricant solutions were prepared. It showed quite similar wear property to bovine serum by controlling the composition. These results serve as a guide to propose the new lubricant suitable for the wear characterization of hip joint.

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Oberbach, Thomas, Sabine Begand et Christian Kaddick. « Surface Resistance of Dispersion Ceramics against Third Body Abrasion ». Key Engineering Materials 396-398 (octobre 2008) : 161–64. http://dx.doi.org/10.4028/www.scientific.net/kem.396-398.161.

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Wear of the articulation partners in artificial joints for hip or knee is known to influence the in vivo survival rate of the implants. Wear amount can be strongly increased if third body wear occurs in the joint gap. Alumina ceramic is noted for a good wear resistance even under these worst case conditions. We tested the wear behaviour of the new dispersion ceramics ZTA (Zirconia Toughened Alumina) and ATZ (Alumina Toughened Zirconia) in comparison to alumina for the couplings ceramic on PE and ceramic on ceramic in a hip joint simulator in presence of third body particles.

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Lestari, W. D., R. Ismail, J. Jamari et A. P. Bayuseno. « Study on Wear Debris Characterization of Polycarbonate Urethane (PCU) as a Bearing of Artificial Hip Joint ». Journal of Physics : Conference Series 2065, n^o 1 (1 novembre 2021) : 012004. http://dx.doi.org/10.1088/1742-6596/2065/1/012004.

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Abstract As with all artificial joints, wear debris is of particular concern due to its effect on both implant life and the in vivo biological reactions that can occur. The purpose of the research is to study debris characterization of PCU. Wear particle is produced from testing the PCU material using a pin on disc wear tester within 50000 cycles. This study showed that the PCU wear debris gotten from the simulator had various different shapes, including laminar and spherical types. The morphology of worn surface and wear debris analysis showed that wear mechanism of PCU were fatigue wear. Thus we conclude that PCU is expected to be a lifetime implantation of artificial joint.

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Williams, S., M. Butterfield, T. Stewart, E. Ingham, M. Stone et J. Fisher. « Wear and deformation of ceramic-on-polyethylene total hip replacements with joint laxity and swing phase microseparation ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 217, n^o 2 (1 février 2003) : 147–53. http://dx.doi.org/10.1243/09544110360579367.

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Wear of polyethylene and the resulting wear debris-induced osteolysis remains a major cause of long-term failure in artificial hip joints. There is interest in understanding engineering and clinical conditions that influence wear rates. Fluoroscopic studies have shown separation of the head and the cup during the swing phase of walking due to joint laxity. In ceramic-on-ceramic hips, joint laxity and microseparation, which leads to contact of the head on the superior rim of the cup, has led to localized damage and increased wear in vivo and in vitro. The aim of this study was to investigate the influence of joint laxity and microseparation on the wear of ceramic on polyethylene artificial hip joints in an in vitro simulator. Microseparation during the swing phase of the walking cycle produced contact of the ceramic head on the rim of the polyethylene acetabular cup that deformed the softer polyethylene cup. No damage to the alumina ceramic femoral head was found. Under standard simulator conditions the volume change of the moderately crosslinked polyethylene cups was 25.6 ± 5.3 mm3/million cycles and this reduced to 5.6 ± 4.2 mm3/million cycles under microseparation conditions. Testing under microseparation conditions caused the rim of the polyethylene cup to deform locally, possibly due to creep, and the volume change of the polyethylene cup when the head relocated was substantially reduced, possibly due to improved lubrication. Joint laxity may be caused by poor soft tissue tension or migration and subsidence of components. In ceramic-on-polyethylene acetabular cups wear was decreased with a small degree of joint laxity, while in contrast in hard-on-hard alumina bearings, microseparation accelerated wear. These findings may have significant implications for the choice of fixation systems to be used for different types of bearing couples.

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von Skrbensky, Gobert, Karoline Mühlbacher, Emir Benca, Alexander Kolb, Reinhard Windhager, Georg Reischl et Georg Reinisch. « Evaluation of Aerosol Electrospray Analysis of Metal-on-Metal Wear Particles from Simulated Total Joint Replacement ». Sensors 19, n^o 17 (30 août 2019) : 3751. http://dx.doi.org/10.3390/s19173751.

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Wear is a common cause for aseptic loosening in artificial joints. The purpose of this study was to develop an automated diagnostical method for identification of the number and size distribution of wear debris. For this purpose, metal debris samples were extracted from a hip simulator and then analyzed by the electrospray method combined with a differential mobility analyzer, allowing particle detection ranging from several nanometers up to 1 µm. Wear particles were identified with a characteristic peak at 15 nm. The electrospray setup was successfully used and validated for the first time to characterize wear debris from simulated total joint replacement. The advantages of this diagnostic method are its time- and financial efficiency and its suitability for testing of different materials.

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Galvin, A., C. Brockett, S. Williams, P. Hatto, A. Burton, G. Isaac, M. Stone, E. Ingham et J. Fisher. « Comparison of wear of ultra-high molecular weight polyethylene acetabular cups against surface-engineered femoral heads ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 222, n^o 7 (1 octobre 2008) : 1073–80. http://dx.doi.org/10.1243/09544119jeim407.

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Alumina ceramic heads have been previously shown to reduce polyethylene wear in comparison to cobalt chrome (CoCr) heads in artificial hip joints. However, there are concerns about the brittle nature of ceramics. It is therefore of interest to investigate ceramic-like coatings on metallic heads. The aim of this study was to compare the friction and wear of ultra-high molecular weight polyethylene (UHMWPE) against alumina ceramic, CoCr, and surface-engineered ceramic-like coatings in a friction simulator and a hip joint simulator. All femoral heads tested were 28 mm diameter and included: Biolox™ Forte alumina, CoCr, arc evaporative physical vapour deposition (AEPVD) chromium nitride (CrN) coated CoCr, plasma-assisted chemical vapour deposition (PACVD) amorphous diamond-like carbon (aDLC) coated CoCr, sputter CrN coated CoCr, reactive gas controlled arc (RGCA) AEPVD titanium nitride (TiN) coated CoCr, and Graphit-iC™ coated CoCr. These were articulated against UHMWPE acetabular cups in a friction simulator and a hip joint simulator. Alumina and CoCr gave the lowest wear volumes whereas the sputter coated CrN gave the highest. Alumina also had the lowest friction factor. There was an association between surface parameters and wear. This study indicates that surface topography of surface-engineered femoral heads is more important than friction and wettability in controlling UHMWPE wear.

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Oberbach, Thomas, Wilfried Glien et Christian Kaddick. « Third-Body-Wear as a Risk Factor in Joint Endoprosthetics ». Key Engineering Materials 284-286 (avril 2005) : 995–98. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.995.

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It is well known, that wear of the articulation partners of hip joint prostheses affect the long-term durability of the implants in vivo. The wear is dramatically increased if particles in the artificial joint gap act as third body. Those particles can also occur after a fracture of a ceramic component. Until now there are some different guidelines which coupling (metal-polyethylene, ceramic-polyethylene, ceramic-ceramic) should be used for revision. We tested and compared the wear behaviour of a ceramic-PE-pairing and a ceramic-ceramic-pairing under third body wear conditions with alumina-particles in a hip joint simulator.

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Streicher, R. M., M. Semlitsch, R. Schön, H. Weber et C. Rieker. « Metal-On-Metal Articulation for Artificial Hip Joints : Laboratory Study and Clinical Results ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 210, n^o 3 (septembre 1996) : 223–32. http://dx.doi.org/10.1243/pime_proc_1996_210_416_02.

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As wear is inevitable with artificial joint replacement, it has to be minimized to avoid possible aseptic loosening following osteolysis due to particle-initiated foreign body reaction. Co-Cr-Mo-C alloys have a long history with only minimum wear when articulating with themselves. This investigation shows that the choice of the alloy has an effect on the wear rate of this articulation couple. Tribological studies in a screening device, a pendulum apparatus and a hip joint simulator showed a marked influence of the environment as well as the diameter of the implants with metal-on-metal articulation. A wear-resistant combination with low friction characteristics has been developed by using a wrought Co-Cr-Mo-C alloy and reducing the implant diameter to 28 mm. Clinical wear rates are comparable with laboratory data and demonstrate the potential of the metal-on-metal articulation to solve the problem of wear-induced osteolysis of hip joint endoprostheses.

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Ikeda, Junji, Takayuki Murakami, T. Sasaki, T. Shimozono, Y. Shouyama et M. Iwamoto. « Wear and Corrosion Resistance of Low Temperature Degradation Free ZTA for Artificial Joint ». Key Engineering Materials 720 (novembre 2016) : 296–300. http://dx.doi.org/10.4028/www.scientific.net/kem.720.296.

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Low-temperature-degradation-free (LTD-free) zirconia-toughened alumina (ZTA) has been developed as an alternative to alumina and zirconia. It has been reported that ZTA has more beneficial mechanical characteristics than alumina, because of the stress-induced transformation and the spontaneous transformation of the zirconia phase that occurs for some ZTA in a hydrothermal environment. To achieve high-reliability artificial-joint prostheses, it is necessary to improve both the mechanical characteristics and phase stability of the joint material simultaneously. Thus, in this study, we evaluate the wear characteristics and corrosion resistance of LTD-free ZTA using a hip wear simulator, so as to confirm the long-term stability and reliability of this material in clinical use. The ZTA with advantageous mechanical characteristics used in this study has extremely high wear and corrosion resistance. Therefore, this ZTA could be quite useful as a bearing material in artificial joints for longer-term clinical use. It is also confirmed that the newly developed LTD-free ZTA is extremely stable under sliding conditions. Thus, it can be expected that the initial superior surface characteristics will be maintained through long-term clinical use.

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Zhang, Lei Lei, He Jun Li, Ke Zhi Li, Ling Jun Guo, Wei Feng Cao et Xue Tao Shen. « Biotribology Behavior of Ultra-High Molecular Weight Polyethylene against Carbon/Carbon Composites Used for Hip Joint Replacement ». Materials Science Forum 685 (juin 2011) : 327–30. http://dx.doi.org/10.4028/www.scientific.net/msf.685.327.

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In order to investigate the biotribology behavior of a novel artificial joint pair composed of a carbon/carbon composite femoral head and an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup, a hip joint simulator was employed to predict the clinical wear behavior with a constant load and a lubricant of newborn calf serum. The worn surface and the wear particles generated were analyzed by scanning electron microscopy and laser particle size analyzer. The results showed that the worn surface of UHMWPE had a ripple-like morphology with plentiful furrows. The wear particles generated had various morphologies with a size concentrated at about 15 μm.

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FUJIKAWA, Takamasa, Nobuo SAKAI, Kazuhiro NAKASHIMA, Yoshinori SAWAE et Teruo MURAKAMI. « F24 Evaluation of friction and wear property of artificial cartilage by knee joint simulator ». Proceedings of Conference of Kyushu Branch 2007.60 (2007) : 203–4. http://dx.doi.org/10.1299/jsmekyushu.2007.60.203.

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Wicaksono, Fabian Singgih, T. Towijaya, Eko Saputra, Rifky Ismail, Mohammad Tauviqirrahman, J. Jamari et Athanasius P. Bayuseno. « Study of Sensor Deflection in Hip Simulator : Numerical and Experimental Method ». E3S Web of Conferences 73 (2018) : 01022. http://dx.doi.org/10.1051/e3sconf/20187301022.

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A lot of Hip Joint Simulator have been made nowadays, most of them use different structure and method. This research reports a pin-on-ring tribometer design that is used to became hip joint simulator based on the movement of the salat (salat gait). Modified femoral head and acetabular cup holder are performed, to design a reciprocating motion for simulation of artificial hip movement. An interesting finding from this study is a new linked-bar mechanism that leads to the ability to move femoral head against the acetabular cup and measure wear volume of an THR patients during normal salat gait. The designed motion angle is 121.5° in the flexion direction and 15.5° in the direction of abduction. Linked bar for sensor dial indicator have enough adjustment, but there is still a movement that is not rigid upon running hip joint process simulator. This research concentrates on the bar is already linked in accordance or not when compared with the data in the simulate on a computer. Estimation error and deviations that occur between numerical and experimental is going forward to improve hip joint simulator Undip to be more precise and relevant research to use THR Undip.

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Fisher, J., J. Bell, P. S. M. Barbour, J. L. Tipper, J. B. Mattews, A. A. Besong, M. H. Stone et E. Ingham. « A novel method for the prediction of functional biological activity of polyethylene wear debris ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 215, n^o 2 (1 février 2001) : 127–32. http://dx.doi.org/10.1243/0954411011533599.

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The comparative performance of artificial hip joints has been extensively investigated in vitro through measurements of wear volumes. in vivo a major cause of long-term failure is wear-debris-induced osteolysis. These adverse biological reactions are not simply dependent on wear volume, but are also controlled by the size and volumetric concentration of the debris. A novel model is presented which predicts functional biological activity; this is determined by integrating the product of the biological activity function and the volumetric concentration function with the wear volume over the whole particle size range. This model combines conventional wear volume measurements with particle analysis and the output from in vitro cell culture studies to provide a new indicator of osteolytic potential. The application of the model is demonstrated through comparison of the functional biological activity of wear debris from polyethylene acetabular cups articulating under three different conditions in a hip joint simulator.

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MATSUBARA, Oki, Gaku IWATA, Masashi ATARASHI, Koichi OTSUKA, Hidehiko HIGAKI et Yoshitaka NAKANISHI. « 502 Influence of bulk temperature rise in the wear test of artificial hip joint with a joint simulator ». Proceedings of Conference of Chugoku-Shikoku Branch 2013.51 (2013) : _502–1_—_502–2_. http://dx.doi.org/10.1299/jsmecs.2013.51._502-1_.

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Chen, Guomei, Zifeng Ni, Shanhua Qian et Yongwu Zhao. « Biotribological behaviour of Vitamin E-blended highly cross-linked UHMWPE in a hip joint simulator ». Industrial Lubrication and Tribology 68, n^o 5 (8 août 2016) : 548–53. http://dx.doi.org/10.1108/ilt-09-2015-0130.

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Purpose The purposes of this paper are to investigate the biotribological behaviour of Vitamin E-blended highly cross-linked ultra-high molecular weight polyethylene (HXL-UHMWPE) under multi-directional motion by using a CUMT II artificial joint hip simulator and compare it with HXL-UHMWPE and conventional UHMWPE. Design/methodology/approach The biotribological behaviour of conventional, highly cross-linked and Vitamin E-blended highly cross-linked UHMWPE acetabular cups counterfaced with CoCrMo alloy femoral head under multi-directional motion were investigated by using CUMT-II artificial hip joint simulator for one-million walking cycles. The test environment was at 36.5 ± 0.5°C and 25 per cent bovine serum was used as lubricant. A Paul cycle load with a peak of 784 N was applied; the motion and loading were synchronized at 1 Hz. Findings The wear resistance of Vitamin E-blended highly cross-linked UHMWPE was significantly higher than that of highly cross-linked and conventional UHMWPE. The wear marks observed from the worn surface of UHMWPE were multi-directional, with no dominant wear direction. Only abrasion occurred on the surface of Vitamin E-blended highly cross-linked UHMWPE, while yielding and accumulated plastic flow processes occurred on the surface of conventional UHMWPE and flaking-like facture and abrasion occurred on the surface of highly cross-linked UHMWPE. Originality/value Besides the prevention of oxidative degradation, blending with Vitamin E can also reduce the incidence of fatigue crack occurred in the surface layer of HXL-UHMWPE samples. Therefore, the wear resistance of HXL-UHMWPE under multi-directional motion can be further enhanced by blending with Vitamin E.

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Bell, J., J. L. Tipper, E. Ingham, M. H. Stone et J. Fisher. « The influence of phospholipid concentration in protein-containing lubricants on the wear of ultra-high molecular weight polyethylene in artificial hip joints ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 215, n^o 2 (1 février 2001) : 259–63. http://dx.doi.org/10.1243/0954411011533661.

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There is considerable interest in the wear of polyethylene and the resulting wear-debrisinduced osteolysis in artificial hip joints. Proteins play an important role as boundary lubricants in vivo in the pseudosynovial fluid, and these are reproduced in in vitro tests through the use of bovine serum. Little is known, however, about the effect of phospholipid concentrations within proteinaceous solutions on the wear of ultra-high molecular weight polyethylene (UHMWPE). The effects of protein-containing lubricants with 0.05, 0.5 and 5 per cent (w/v) phosphatidyl choline concentrations on the wear of ultra-high molecular weight polyethylene (UHMWPE) were compared with 25 per cent (v/v) bovine serum which had 0.01 per cent (w/v) lipid; the effects were compared in a hip joint simulator with smooth (n = 4) and scratched (n = 3) femoral heads. The control bovine serum lubricant produced UHWMPE wear of 55 and 115mm3/106 cycles on the smooth and rough heads respectively. The increased phospholipid concentration significantly reduced the wear rate. At the higher concentration (5% w/v phosphatidyl choline) the average wear was reduced to less than 2 mm3/106 cycles. Even with the relatively low concentrations of 0.05% w/v phosphatidyl choline the wear was reduced by at least threefold compared with the bovine serum tests for both the smooth and rough femoral heads. There may be considerable differences in the phospholipid concentrations in patients' synovial fluid and this is highly likely to produce considerable variation in wear rates. In vitro, differences in the phospholipid concentration of lubricants may also cause variation in wear rates between different simulator tests.

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Joyce, T. J., et A. Unsworth. « The wear of artificial finger joints using different lubricants in a new finger wear simulator ». Wear 250, n^o 1-12 (octobre 2001) : 199–205. http://dx.doi.org/10.1016/s0043-1648(01)00657-3.

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Liu, Li, Lin Wei et Meng Yu. « Service Life Study of the Artificial Knee-Joints of Crossed Pairing ». Advanced Materials Research 655-657 (janvier 2013) : 1963–67. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.1963.

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The stress relationship between the artifical knee-joints of the same pairing and crossed pairing was studied by the contrastive contact analysis of finite element simulation in different angles and conditions. The service lives of the artifical knee-joints of different pairing were studied based on the above result and Archard wear design calculation theory to expand the application of existing artificial knee-joints. The result shows that, the maximal contact stresses of the artifical knee-joints of crossed pairing are more than those of the artifical knee-joints of the same pairing, and the more different pairing types are, the more obvious stress growths are. The service life of the artifical knee-joint of 3/3 pairing is 28.42 years, and the service lives of 3/2.5 pairing and 3/4 pairing are 27.08 years and 25.76 years respectively.

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OTSUKA, Koichi, Katsuhiro HIRAGI et Hidehiko HIGAKI. « Temperature behavior of sliding portions in the wear test of artificial joint materials using a joint simulator and its influence ». Transactions of the JSME (in Japanese) 83, n^o 850 (2017) : 16–00562. http://dx.doi.org/10.1299/transjsme.16-00562.

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Lu, Z., et H. McKellop. « Frictional heating of bearing materials tested in a hip joint wear simulator ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 211, n^o 1 (1 janvier 1997) : 101–8. http://dx.doi.org/10.1243/0954411971534728.

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In a hip simulator wear test using bovine serum as a lubricant, the heat generated by ball-cup friction may cause precipitation of the proteins from the lubricant. The resultant accumulation of a solid layer of precipitated protein between the ball and cup could artificially protect the bearing surfaces from wear, in a manner that does not occur in vivo. Alternatively, the gradual depletion of the soluble proteins could interfere with their ability to act as boundary lubricants on the bearing surfaces, thereby artificially increasing the wear rate. Because the rate of protein precipitation may depend on the maximum temperature at the bearing surfaces during sliding, rather than the mean temperature of the bulk lubricant, this study determined the transient surface temperatures using an array of thermocouples embedded in acetabular cups of GUR 415 ultra-high molecular weight polyethylene (UHMWPE) and femoral balls of metal or ceramic, in conjunction with a finite element model of the temperature distribution. The prostheses were tested at one cycle/s under a Paul-type, physiological load profile with 2030 N maximum force, with the load cycle synchronized to the motion cycle. The steady state temperatures of the bulk lubricant were 38°C for the zirconia balls, 36°C for the cobalt-chromium and 33°C for the alumina. However, the corresponding surface temperatures of the polyethylene, calculated with the finite element model, were 99°C with zirconia ceramic, 60°C with cobalt-chromium alloy, and 45°C with alumina ceramic. The rank order of the surface temperatures corresponded to the relative amounts of protein that were precipitated in the test chambers during wear tests with these materials.

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Unsworth, A., M. J. Pearcy, E. F. T. White et G. White. « Frictional Properties of Artificial Hip Joints ». Engineering in Medicine 17, n^o 3 (juillet 1988) : 101–4. http://dx.doi.org/10.1243/emed_jour_1988_017_029_02.

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A new generation of hip replacements has been designed incorporating compliant layers to promote fluid film lubrication when the joints are implanted in patients. Tests in the Durham hip function simulator show that the friction in these joints is up to an order of magnitude lower than in currently used prostheses, and because this is due to complete separation of the rubbing surfaces, wear ought to be vastly reduced. Experiments have shown that the best results are achieved with compliant surfaces of hardness between 4 and 8 N/mm2. Such surfaces produce coefficients of friction of the order of 5 × 10-3.

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Oberbach, Thomas, Sabine Begand, Wilfried Glien et Christian Kaddick. « Investigation of Aged Dispersion Ceramics by Means of Hip Simulator ». Key Engineering Materials 361-363 (novembre 2007) : 771–74. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.771.

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Wear of hip implants is a significant problem for the life expectancy of artificial joints. By using alumina ceramic on ceramic couplings the wear can be decreased. But for further improvement of the safety of THR the aim is the development of new ceramic materials. For orthopaedic applications an Alumina Toughened Zirconia Ceramic ATZ (80% ZrO2-20%Al2O3) and a Zirconia Toughened Alumina ZTA (25% ZrO2-75%Al2O3) were tested regarding their tribological behaviour by means of hip simulator testing after hydrothermal treatment. The absolute wear amount for the aged samples after 5 million cycles is slightly increased on a very low level, but even less wear than for common alumina pairings. In consideration of these excellent results both dispersion ceramics are highly suitable for long term applications.

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Ishikawa, H., H. Fujiki et K. Yasuda. « Contact Analysis of Ultrahigh Molecular Weight Polyethylene Articular Plate in Artificial Knee Joint During Gait Movement ». Journal of Biomechanical Engineering 118, n^o 3 (1 août 1996) : 377–86. http://dx.doi.org/10.1115/1.2796020.

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To understand the wear mechanism of the ultrahigh molecular weight polyethylene (UHMWPE) articular plate used in artificial knee joints, the cyclic contact behavior of the plate during gait movement was analyzed using the constitutive equation for cyclic plasticity. In this study, two-dimensional plane strain model was employed and the contact behavior of femoral and tibial components was simulated by translating the contact stress distribution which was calculated from elasto-plastic indentation analysis of two components. For analytical model, the anatomical type artificial knee joint was employed and the effect of the shape of contact surface on the wear behavior of the plate was investigated. As a result, it was clarified that the wear of the plate should occur both from the surface and the subsurface of the plate and the wear behavior of the plate should be closely related with the shape of contact surface. Then the optimum shape of contact surface could be designed using this method.

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Kaneeda, Tosiaki, Masato Tamiya, Hiroshi Matsuura, Hisashi Matsushita, Hiroaki Kuno, Kozaburo Hayashi et Kunihiko Fujiwara. « 0939 Wear properties evaluation of metal-on-metal artificial joints using hip simulator. » Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2009.22 (2010) : 351. http://dx.doi.org/10.1299/jsmebio.2009.22.351.

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Hongtao, Liu, Ge Shirong, Cao Shoufan et Wang Shibo. « Comparison of wear debris generated from ultra high molecular weight polyethylene in vivo and in artificial joint simulator ». Wear 271, n^o 5-6 (juin 2011) : 647–52. http://dx.doi.org/10.1016/j.wear.2010.11.012.

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Hembus, Jessica, Lisa Rößler, Mario Jackszis, Annett Klinder, Rainer Bader et Carmen Zietz. « Influence of Metallic Deposition on Ceramic Femoral Heads on the Wear Behavior of Artificial Hip Joints : A Simulator Study ». Materials 13, n^o 16 (12 août 2020) : 3569. http://dx.doi.org/10.3390/ma13163569.

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Several retrieval studies have reported on metallic depositions on ceramic femoral heads, but the effect on the wear behavior of artificial hip joints has not been investigated in wear simulator studies. In the present study, retrieved ceramic heads with metallic depositions as third particles were tested against cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) liners in a hip wear simulator. The amount of liner wear and expansion of metallic depositions on the heads were determined before and after wear testing with digital microscopy. The surface roughness of the heads was investigated in areas with and without metallic depositions by laser scanning microscopy. After five million load cycles, a non-significant reduction in the metallic formation on the retrieved heads was found. The metallic areas showed a higher surface roughness compared to unconcerned areas. The liners showed a higher wear rate of 1.57 ± 1.36 mg/million cycles for 28 mm heads and 2.42 ± 0.82 mg/million cycles for 36 mm heads with metallic depositions, in comparison with new ceramic heads with a 28 mm size ((−0.06 ± 0.89) mg/million cycles) and 36 mm size ((2.04 ± 0.46) mg/million cycles). Metallic transfer on ceramic heads can lead to an increased surface roughness and higher wear rates at the UHMWPE liners. Therefore, metallic contact of the ceramic femoral head should be avoided.

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Dwi Lestari, Wahyu, Luluk Edahwati, Wiliandi Saputro, Ahmad Khairul Faizin, Radissa Dzaky Issafira et Nurmala Shanti Dera. « Investigation The Effect of Clearance and Body Weight on The Contact Pressure of Metal on PCU Hip Prosthesis using Finite Element Method ». E3S Web of Conferences 328 (2021) : 07014. http://dx.doi.org/10.1051/e3sconf/202132807014.

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A common problem with artificial hip replacements is increased wear of the material in contact. Materials that are in contact result in contact pressure caused by the patient's daily activities so that it triggers wear. This study adopts a finite element method (FEM) to predict wear of the artificial hip joint, by studying the behavior of a hip joint prosthesis that has clearance under a certain load. The aim of this study was to observe contact as a function of clearance and body weight. The modeling uses metal as femoral head and polycarbonate urethane (PCU) material as the acetabular cup. Contact modeling as a hard material in contact with a deformable material. Four variations of clearance (0.001, 0.005, 0.01, 0.016) and three variations of body weight (500N, 700N, and 1000N) were used in this study. The simulation results show that the lower the distance and weight, the lower the contact pressure.

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Chen, Hui, Qingliang Wang, Wen Cui et Yong Luo. « Fractal dimension and size distribution characteristics of ultrahigh- molecular-weight polyethylene wear particles in condition of artificial knee joint simulator ». Annals of Joint 2 (novembre 2017) : 69. http://dx.doi.org/10.21037/aoj.2017.10.11.

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Milone, Dario, Giacomo Risitano, Alessandro Pistone, Davide Crisafulli et Fabio Alberti. « A New Approach for the Tribological and Mechanical Characterization of a Hip Prosthesis Trough a Numerical Model Based on Artificial Intelligence Algorithms and Humanoid Multibody Model ». Lubricants 10, n^o 7 (18 juillet 2022) : 160. http://dx.doi.org/10.3390/lubricants10070160.

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In recent years, thanks to the development of additive manufacturing techniques, pros-thetic surgery has reached increasingly cutting-edge levels, revolutionizing the clinical course of patients suffering from joint arthritis, rheumatoid arthritis, post-traumatic arthrosis, etc. This work aims to evaluate the best materials for prosthetic surgery in hip implants from a tribological and mechanical point of view by using a machine-learning algorithm coupling with multi-body modeling and Finite Element Method (FEM) simulations. The innovative aspect is represented by the use of machine learning for the creation of a humanoid model in a multibody software environment that aimed to evaluate the load and rotation condition at the hip joint. After the boundary conditions have been defined, a Finite Element (FE) model of the hip implant has been created. The material properties and the information on the tribological behavior of the material couplings under investigation have been obtained from literature studies. The wear process has been investigated through the implementation of the Archard’s wear law in the FE model. The results of the FE simulation show that the best wear behavior has been obtained by CoCr alloy/UHMWPE coupling with a volume loss due to a wear of 0.004 μm3 at the end of the simulation of ten sitting cycles. After the best pairs in terms of wear has been established, a topology optimization of the whole hip implant structure has been performed. The results show that, after the optimization process, it was possible to reduce implant mass making the implant 28.12% more lightweight with respect to the original one.

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Affatato, Saverio, et Alessandro Ruggiero. « A Perspective on Biotribology in Arthroplasty : From In Vitro toward the Accurate In Silico Wear Prediction ». Applied Sciences 10, n^o 18 (10 septembre 2020) : 6312. http://dx.doi.org/10.3390/app10186312.

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Nowadays hip arthroplasty is recognized as one of the most successful orthopedic surgical procedures, even if it involves challenges to overcome, such that lately, younger and more active patients are in need of total arthroplasty. Wear is still one of the main issues affecting joint prostheses endurance, and often causes loosening accompanied by implant failures. Actual in vitro wear tests executed by mechanical simulators have a long duration, are very expensive, and do not take into account all the possible daily activities of the patients; thus, the challenge to obtain a complete in silico tribological and dynamical model of (bio) tribo-systems could give the possibility to overcome the actual testing procedures and could contribute as a tool for a more accurate tribological design of human prostheses. This prospective paper is intended to underline actual research trends toward the challenge of having accurate numerical algorithms to be used both in preclinical testing and in the optimizations of the prostheses design. With this aim we depicted the possible in silico approach in artificial joints’ wear assessment over time, accounting for contact mechanics, numerical stress–strain analysis, musculoskeletal multibody, and synovial lubrication modelling (boundary/mixed, hydrodynamic, and elastohydrodynamic).

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Fullam, Spencer, Jade He, Caroline S. Scholl, Thomas M. Schmid et Markus A. Wimmer. « Competitive Binding of Bilirubin and Fatty Acid on Serum Albumin Affects Wear of UHMWPE ». Lubricants 8, n^o 5 (10 mai 2020) : 53. http://dx.doi.org/10.3390/lubricants8050053.

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Total Joint Replacement (TJR) devices undergo standardized wear testing in mechanical simulators while submerged in a proteinaceous testing solution to mimic the environmental conditions of artificial joints in the human body. Typically, bovine calf serum is used to provide the required protein content. However, due to lot-to-lot variability, an undesirable variance in testing outcome is observed. Based on an earlier finding that yellowish-orange serum color saturation is associated with wear rate, we examined potential sources of this variability, by running a comparative wear test with bilirubin; hemin; and a fatty acid, oleic acid, in the lubricant. All these compounds readily bind to albumin, the most abundant protein in bovine serum. Ultrahigh molecular weight polyethylene (UHMWPE) pins were articulated against CoCrMo discs in a pin-on-disc tribometer, and the UHMWPE wear rates were compared between lubricants. We found that the addition of bilirubin increased wear by 121%, while hemin had a much weaker, insignificant effect. When added at the same molar ratio as bilirubin, the fatty acid tended to reduce wear. Additionally, there was a significant interaction with respect to bilirubin and hemin in that UHMWPE wear rate decreased with increasing fatty acid concentration. We believe the conformational change in albumin by binding bilirubin makes it more likely to form molecular bridges between UHMWPE and the metal counterface, thus increasing adhesive wear. However, fatty acids compete for binding sites on albumin, and can prevent this conformational change. Hence, the protein is stabilized, and the chance for albumin to form bridges is lowered. Ultimately, UHMWPE wear rate is driven by the competitive binding of bilirubin and fatty acid to albumin.

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Zach, L., S. Konvickova et P. Ruzicka. « Finite Element Analysis of the Lower Extrtemity - Hinge Knee Behavior Under Dynamic Load ». International Journal of Mathematics and Computers in Simulation 15 (27 novembre 2021) : 89–91. http://dx.doi.org/10.46300/9102.2021.15.16.

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A key goal of joint endoprosthesis is to become a full-featured functional and anatomical replacement. The joint damage may occur for several reasons - primarily a disease of different nature and magnitude, resulting in gradual and irreversible changes and in an extreme solution in the implantation of artificial joints. However, there should be also mentioned accidents leading to joint destruction, which are often "trigger mechanism" of the disease. This work therefore presents a dynamic computational finite element analysis of a hinge-type knee replacement, which aim to streamline and accelerate the development of knee endoprosthesis. It tackles a question of the overall strength of the implant and detects sites of elevated concentrations of stresses that may be potential sources of implant damages. It also studies the behavior of the endoprosthesis under dynamic loads with emphasis on the study of the shape and size of the contact surfaces, which are closely related to the size of the contact pressure and material wear. Aside the hinged knee replacement, the computational model consisted of femur, fibula, tibia, patella and 25 most important muscles of the lower limb. Due to realistic definition of the boundary conditions, this model is suitable for investigation of invivo knee joint replacement behavior.

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Rasool, Ghulam, Yousuf El Shafei et Margaret M. Stack. « Mapping Tribo-Corrosion Behaviour of TI-6AL-4V Eli in Laboratory Simulated Hip Joint Environments ». Lubricants 8, n^o 7 (30 juin 2020) : 69. http://dx.doi.org/10.3390/lubricants8070069.

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Wear and corrosion in artificial hip replacements are known to result in metal ion release and wear debris induced osteolysis. This may lead to pain and sensitivity for patients. This infers that pre-clinical testing is critical in determining the long-term performance, safety, and reliability of the implant materials. For this purpose, micro-abrasion-corrosion tests were carried out on a biocompatible material, Ti-6Al-4V ELI, using a T-66, Plint micro-abrasion test rig in conjunction with Gill Ac corrosion testing apparatus for the range of applied loads and electrical potentials in the hip joint simulated environment. A Ringer’s solution, with and without an abrasive particle (silicon carbide), was used to enable the interactions between abrasion and corrosion. In this paper, the effects of applied load and electrochemical potential on the tribo-corrosion behaviour of Ti-6Al-4V in a bio-simulated environment are presented. The wastage, micro-abrasion-corrosion mechanisms, and synergy behaviour were identified and mapped. A significant difference in corrosion current densities was observed in the presence of abrasive particles, suggesting the removal of the protective oxide layer. The results also indicate that Ti-6Al-4V had significant abrasive wear loss when coupled with a ceramic counterpart. According to the mechanism, micro-abrasion plays a predominant role in the abrasion-corrosion behaviour of this material and the material losses by mechanical processes are substantially larger than losses, due to electrochemical processes.

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Nevelos, J., E. Ingham, C. Doyle, R. Streicher, A. Nevelos, W. Walter et J. Fisher. « Microseparation of the centers of alumina-alumina artificial hip joints during simulator testing produces clinically relevant wear rates and patterns ». Journal of Arthroplasty 15, n^o 6 (septembre 2000) : 793–95. http://dx.doi.org/10.1054/arth.2000.8100.

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Fabry, Christian, Sven Herrmann, Michael Kaehler, Ernst-Dieter Klinkenberg, Christoph Woernle et Rainer Bader. « Generation of physiological parameter sets for hip joint motions and loads during daily life activities for application in wear simulators of the artificial hip joint ». Medical Engineering & ; Physics 35, n^o 1 (janvier 2013) : 131–39. http://dx.doi.org/10.1016/j.medengphy.2012.07.014.

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Al Hakim, Reza Azizul Nasa, Sigit Arrohman, Eko Saputra, Iwan Budi Anwar, J. Jamari, Rifky Ismail, Athanasius P. Bayuseno et Mohammad Tauviqirrahman. « The Contact Simulation Comparison of UHMWPE to the Crosslink Intensity Effect ». E3S Web of Conferences 73 (2018) : 12014. http://dx.doi.org/10.1051/e3sconf/20187312014.

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Ultra High Molecular Weight Polyethylene called UHMWPE is a unique polymer material that has excellent physical and mechanical properties. UHMWPE material is frequently used in prosthesis. One example of UHMWPE uses in prosthesis is acetabular liner which is one component for Total Hip Joint Replacement (THR) and can also be found for bearing surfaces on the knee, ankle, shoulder, and connective tissue of the joint. UHMWPE material is made by compression molding process. However, UHMWPE wear often causes the failure of artificial hip joints. Therefore, a treatment to reduce the crosslink method is performed. The purpose of this study was to determine the crosslink effect in UHMWPE material. The method used for this analysis is ABAQUS 6-13 software. On bipolar model, the 3000 N load is applied in the FEM model. The crosslink dose used in this analysis was 50kgy, 75kgy, and 100kgy. The results obtained are that UHMWPE that has received by gamma irradiation treatment can receive a smaller stress distribution. The results of the simulation for UHMWPE without irradiation produced 0.759 stress distributions; 50kgy crosslink dose has 0.666 stress distributions; 75kgy crosslink dose has 0.662 stress distributions; and 100kgy crosslink dose has 0.660 stress distributions. This result proved that UHMWPE which has received crosslink can receive a better stress distribution. For the result crosslink with 100kgy dose received the best number of stress distributionss.

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Rondinella, Alfredo, Elia Marin, Brian J. McEntire, Ryan Bock, B. Sonny Bal, Wen Liang Zhu, Kengo Yamamoto et Giuseppe Pezzotti. « Bioceramics are Not Bioinert : The Role of Oxide and Non-Oxide Bioceramics on the Oxidation of UHMWPE Components in Artificial Joints ». Key Engineering Materials 782 (octobre 2018) : 165–75. http://dx.doi.org/10.4028/www.scientific.net/kem.782.165.

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The following research is aimed at understanding the influence of Zirconia-Toughened Alumina (ZTA) and Silicon Nitride (Si3N4) on Ultra-High Molecular Weight Polyethylene (UHMWPE) acetabular liners. Bioceramic femoral heads were systematically tested against UHMWPE in controlled environment according to static/load-free coupling in hydrothermal environment, pin-on-ball wear testing, and hip-simulator wear testing. In addition, a retrieved ZTA femoral head has been analyzed and results have been compared to the simulations. Experimental results from X-ray photoelectron (XPS), cathodoluminescence (CL), Raman and Fourier-Transformed Infrared spectroscopy suggest that, despite conventional notions imply that bioceramics are inert, the surface chemistry of bioceramics was relevant to the oxidation rate of polyethylene liners. Non-biointertness could either be advantageous or disadvantageous toward polyethylene oxidation. The main reason resides in the peculiar chemical interactions between polyethylene and different ceramics, and, more specifically, depends on the direction of oxygen flow at the interface between the ceramic and the polymer. ZTA femoral heads were found to release a non-negligible amount of oxygen moieties from their surfaces, thus accelerating oxidative degradation of polyethylene. Conversely, Si3N4 ceramics exerted a protective role towards the polyethylene liner by scavenging oxygen from the tribolayer. The results of this work provide new insights into the interaction between bioceramics and polymers, which should also be considered when designing the next generation artificial hip joints with significantly elongated lifetimes.

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SU, YONGLIN, ZENGLIANG FU, PEIRAN YANG et CHENGTAO WANG. « A FULL NUMERICAL ANALYSIS OF ELASTOHYDRODYNAMIC LUBRICATION IN KNEE PROSTHESIS UNDER WALKING CONDITION ». Journal of Mechanics in Medicine and Biology 10, n^o 04 (décembre 2010) : 621–41. http://dx.doi.org/10.1142/s0219519410003605.

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Lubrication plays an important role in reducing prosthetic wear. Time-dependent elastohydrodynamic lubrication simulation for total knee replacements was carried out under physiological loading and motions of a gait cycle. In numerical implement, a simplified ellipsoid-on-plane configuration was introduced to represent the artificial knee joint. Load and motions came from ISO standard, and both anterior–posterior displacement and flexion–extension rotation were considered to realize sliding and rolling motions of the knee. The governing Reynolds and elasticity equations were solved simultaneously using the multigrid technique. The elastic deformation was calculated based on the constrained column model. The results show that: (i) under the combination of entraining and squeeze-film actions throughout the walking cycle, the predicted central film thickness decreases during stance phase and keeps a relatively larger value in swing phase; (ii) high joint conformity helps to reduce hydrodynamic pressure and increase lubrication film thickness; (iii) the thickness of ultra-high molecular weight polyethylene layer and its properties also have influence on the lubrication performance in artificial knee replacement. Based on the aforementioned EHL analysis, potential surface damage of knee implants can be further evaluated.

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Ranuša, Matúš, Markus A. Wimmer, Spencer Fullam, Martin Vrbka et Ivan Křupka. « Analysis of Friction in Total Knee Prosthesis during a Standard Gait Cycle ». Lubricants 9, n^o 4 (3 avril 2021) : 36. http://dx.doi.org/10.3390/lubricants9040036.

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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.

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Melkou, Lamia, et Mustapha Hamerlain. « Classical Sliding and Generalized Variable Structure Controls for a Manipulator Robot Arm with Pneumatic Artificial Muscles ». International Journal of System Dynamics Applications 3, n^o 1 (janvier 2014) : 47–70. http://dx.doi.org/10.4018/ijsda.2014010103.

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Service robotics is a domain in full effervescence because it allows a human being to interact directly with a robot while guaranteeing both safety and comfort to the human. The pneumatic artificial muscle (PAM), as an actuator, has become a solution increasingly adopted in the applications of service robotics because it provides a robot with joint compliance comparable to that of the human body. Although possessing known qualities, the PAM's nonlinearities make it one of the actuators the most difficult to model. This inconvenience limits the use of classical control as it can result in an unexpected or unwanted behavior of the system. It is thus advisable to opt for robust control algorithms to deal with these problems. Amongst robust controllers, the Classical Variable Structure (CVS) control generating a sliding mode is implemented. This control law is known by its robustness versus modeling errors, parametric uncertainties and external matched disturbances. However, the main disadvantage of this control is the appearance of high frequency oscillations once the sliding surface is reached. This phenomenon known as chattering can cause precision loss and premature actuators' wear. Results in both simulation and experiment show that these oscillations are due to the discontinuous component of the control. Numerous solutions exist for its attenuation. One is presented in this paper, the Generalized Variable Structure (GVS). The objective of this work is the synthesis and implementation of Classical and Generalized Variable Structure Control for a manipulator robot arm actuated by PAMs.

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Saikko, V. « A 12-Station Anatomic Hip Joint Simulator ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 219, n^o 6 (1 juin 2005) : 437–48. http://dx.doi.org/10.1243/095441105x34419.

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A novel 12-station hip joint simulator with an anatomic position of the prosthesis was designed and built. The motion of the simulator consists of flexion-extension and abduction-adduction. The load is of the double-peak type. The validation test was done with three similar 28 mm CoCr-polyethylene joints in diluted calf serum lubricant for 3.3 × 106 cycles. The bearing surfaces of the polyethylene cups were burnished, the CoCr heads were undamaged, the wear particles were in the 0.1-1 μm size range, and the mean wear factor of the polyethylene cups was 5.7 × 10−7 mm3/N m. These essential observations were in good agreement with clinical findings. In addition, three similar 50 mm CoCR/CoCr joints, representing the contemporary large-diameter metal-on-metal articulation were tested. The wear of the CoCr/CoCr joints was calculated from the Co and Cr concentrations of the used lubricant quantified with atomic absorption spectroscopy. The bearing surfaces of the CoCr/CoCr jonits showed mild criss-cross scratching only. The average wear factor of polyethylene cups was 275 times that of the CoCr/CoCr joints. The tribological behaviour of the large-dia. CoCr/CoCr appeared to be dominated by fluid film lubrication, as indicated by very low frictional heating and wear, making it tribologically superior to the conventional CoCr/polyethylene, and therefore very interesting clinically. In conclusion, the simulator proved to be a valid, reliable, practical, economical, and easy-to-operate tool for wear studies of various hip replacement designs.

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Jangid, Vivek, Abhishek Kumar Singh et Abhishek Mishra. « Wear Simulation of Artificial Hip Joints : Effect of Materials ». Materials Today : Proceedings 18 (2019) : 3867–75. http://dx.doi.org/10.1016/j.matpr.2019.07.326.

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Medeiros, Everton C. « Design and Evaluation of a Hip Joint Implant Wear Simulator ». International Journal for Research in Applied Science and Engineering Technology 9, n^o 8 (31 août 2021) : 989–94. http://dx.doi.org/10.22214/ijraset.2021.37531.

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Abstract: Every year a high number of total hip arthroplasty is reported worldwide and an increase in this number is expected. Several factors may cause hip wear, such as osteoarthritis, obesity, traffic accidents and sport practicing. Wear is a concern when considering hip prostheses, since a prosthesis presents finite life that in many cases is shorter than patient life, and leads to substitution. Also, research is constant and new developments have to be tested, which leads to the necessity of testing devices that reproduce real conditions of hip joint implant functioning. This work describes a low-cost device, according to the ISO 12242. The equipment was built, a set of three commercially available prostheses was tested and the results show wear values coherent with those found in literature. It was found a value of wear rate of (13.30 ± 3,81) mg/106 cycles; wear factor found was (0.41 ± 0,09) x 10-6 mm3 /Nm. After testing, the device was evaluated and no component presented significant wear. Keywords: Hip joint simulator; Prostheses; Wear; Arthroplasty; Test machine.

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Ebramzadeh, Edward, Fabrizio Billi, Sophia N. Sangiorgio, Sarah Mattes, Werner Schmoelz et Lawrence Dorr. « Simulation of Fretting Wear at Orthopaedic Implant Interfaces ». Journal of Biomechanical Engineering 127, n^o 3 (2 janvier 2005) : 357–63. http://dx.doi.org/10.1115/1.1894121.

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Osteolysis due to wear debris is a primary cause of failure of total joint replacements. Although debris produced by the joint articulating surfaces has been studied and simulated extensively, fretting wear debris, produced at nonarticulating surfaces, has not received adequate attention. We developed a three-station fretting wear simulator to reproduce in vivo motion and stresses at the interfaces of total joint replacements. The simulator is based on the beam bending theory and is capable of producing cyclic displacement from 3to1000microns, under varying magnitudes of contact stresses. The simulator offers three potential advantages over previous studies: The ability to control the displacement by load, the ability to produce very small displacements, and dynamic normal loads as opposed to static. A pilot study was designed to test the functionality of the simulator, and verify that calculated displacements and loads produced the predicted differences between two commonly used porous ingrowth titanium alloy surfaces fretting against cortical bone. After 1.5 million cycles, the simulator functioned as designed, producing greater wear of bone against the rougher plasma-sprayed surface compared to the fiber-mesh surface, as predicted. A novel pin-on-disk apparatus for simulating fretting wear at orthopaedic implant interfaces due to micromotion is introduced. The test parameters measured with the fretting wear simulator were as predicted by design calculations, and were sufficient to measure differences in the height and weight of cortical bone pins rubbing against two porous ingrowth surfaces, plasma-sprayed titanium and titanium fiber mesh.

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Schlachter, Kelly, et Gladius Lewis. « Design of a First Metatarsophalangeal Joint Simulator ». Journal of the American Podiatric Medical Association 103, n^o 5 (1 septembre 2013) : 411–17. http://dx.doi.org/10.7547/1030411.

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Background: The use of total first metatarsophalangeal joint (MPJ) arthroplasty to treat patients in which the pain, due to a pathological joint, has not been relieved with a conservative method or for which the disease or disorder is at an advanced stage, is popular. Although meta-analysis of clinical results indicates that this surgical option is efficacious, there are problems with implant failure due to wear of the components. Although there is a plethora of designs of this type of implant in clinical use, there are no literature reports on total first MPJ simulators, which may be used to evaluate, for example, the wear rate of a total first MPJ implant. Methods: We designed such a simulator, guided by the biomechanics of the joint. Thus, for example, the implant under test will be articulated at least 40° dorsiflexion, under a 600 N loading, at 1 Hz. Furthermore, the testing stations will be configured to allow testing of any type of first MPJ implant. We also performed a finite element analysis (FEA) study of a model of an articulating station, subjected to a quasi-static load of 1200 N. Results: For an articulating station, 1) the highest von Mises stress occurred at the implant-fixture interface; and 2), for the other parts, the minimum factor of safety, against elastic failure, is approximately 9. Conclusions: The designed joint simulator is mechanically sound and may be used for wear testing of any type of first MPJ implant. (J Am Podiatr Med Assoc 103(5): 411–417, 2013)

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Affatato, Saverio, et Alessandro Ruggiero. « A Critical Analysis of TKR In Vitro Wear Tests Considering Predicted Knee Joint Loads ». Materials 12, n^o 10 (15 mai 2019) : 1597. http://dx.doi.org/10.3390/ma12101597.

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Detailed knowledge about loading of the knee joint is essential for preclinical testing of total knee replacement. Direct measurement of joint reaction forces is generally not feasible in a clinical setting; non-invasive methods based on musculoskeletal modelling should therefore be considered as a valid alternative to the standards guidelines. The aim of this paper is to investigate the possibility of using knee joint forces calculated through musculoskeletal modelling software for developing an in vitro wear assessment protocol by using a knee wear simulator. In particular, in this work we preliminarily show a comparison of the predicted knee joint forces (in silico) during the gait with those obtained from the ISO 14243-1/3 and with those measured in vivo by other authors. Subsequently, we compare the wear results obtained from a knee wear joint simulator loaded by calculated forces in correspondence to the “normal gait” kinematics with those obtained in correspondence to the loads imposed by the ISO. The obtained results show that even if the predicted load profiles are not totally in good agreement with the loads deriving from ISO standards and from in vivo measurements, they can be useful for in vitro wear tests, since the results obtained from the simulator in terms of wear are in agreement with the literature data.

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Kang, L., A. L. Galvin, T. D. Brown, J. Fisher et Z.-M. Jin. « Wear simulation of ultra-high molecular weight polyethylene hip implants by incorporating the effects of cross-shear and contact pressure ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 222, n^o 7 (1 octobre 2008) : 1049–64. http://dx.doi.org/10.1243/09544119jeim431.

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The effect of multi-directional cross-shear (CS) motion and contact pressure on ultra-high molecular weight polyethylene (UHMWPE) wear was investigated in this study, based on an integrated experimental and computational approach. The wear factor as a function of CS was determined experimentally from a multi-directional pin-on-plate wear tester under a nominal contact pressure of 1 MPa. A computational wear model was developed which included the effects of CS as well as the load and sliding distance imposed on the hip joint employing a UHMWPE cup against a metallic femoral head under both gait and Leeds ProSim hip joint simulator conditions. The CS ratios were quantified over the articular surface of the UHMWPE cup and the CS-dependent wear factors derived from multi-directional pin-on-plate studies were applied in the computational wear model. Outputs from the computational wear model were validated independently against an experimental hip simulator study. Comparisons of linear and volumetric wear were made between the computational wear model and the hip simulator testing for a nominal conventional (0 MRad) UHMWPE cup of 28 mm diameter and a highly cross-linked (10 MRad) UHMWPE cup. The difference between the computed and experimental volumetric wear was approximately 30 per cent for the 0 MRad UHMWPE, although the worn areas between the prediction and the measurement were similar. For the 10 MRad UHMWPE, the discrepancy was reduced to 16 per cent. In both cases, the computational model predicted a lower wear rate than the experimental simulator testing. The effect of using alternative wear factors under a different nominal contact pressure of 3 MPa was also considered. The input wear factor to the computational model, derived from a constant loaded pin-on-plate test configuration, may underestimate the dynamic effect due to the variation in the load in the hip joint simulator.

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Watters, E. P. J., P. L. Spedding, J. Grimshaw, J. M. Duffy et R. L. Spedding. « Wear of artificial hip joint material ». Chemical Engineering Journal 112, n^o 1-3 (septembre 2005) : 137–44. http://dx.doi.org/10.1016/j.cej.2005.02.031.

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Fialho, Jorge C., Paulo R. Fernandes, Luis Eça et João Folgado. « Computational hip joint simulator for wear and heat generation ». Journal of Biomechanics 40, n^o 11 (janvier 2007) : 2358–66. http://dx.doi.org/10.1016/j.jbiomech.2006.12.005.

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Saikko, V., P. Paavolainen, M. Kleimola et P. Slätis. « A Five-Station Hip Joint Simulator for Wear Rate Studies ». Proceedings of the Institution of Mechanical Engineers, Part H : Journal of Engineering in Medicine 206, n^o 4 (décembre 1992) : 195–200. http://dx.doi.org/10.1243/pime_proc_1992_206_291_02.

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The aim of the work has been the development of a hip joint simulator for comparative wear rate studies of long duration. A five-station apparatus has been designed, constructed and tested. Five total hip joints can be tested at the same time in identical conditions. The flexion-extension motion and the superior-inferior component of the joint contact force are incorporated. The motion is electromechanical and the loading pneumatic. The angle and load waveforms are fixed and simulate level walking. For accurate wear measurements each station employs a control prosthesis. The conditions of the control prosthesis in regard to loading, exposure to lubricant and environment temperature (37 ± 1°C) are identical to those of the test prosthesis. The acetabular cups can be readily removed for periodic wear measurements and reassembled in exactly the original position. Extensive tests have shown that the simulator is a practical and reliable instrument in the wear rate studies of various designs of total hip joint.

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