Articoli di riviste: "Artificial hip joints"

1

Puccio, Francesca Di. "Biotribology of artificial hip joints". World Journal of Orthopedics 6, n. 1 (2015): 77. http://dx.doi.org/10.5312/wjo.v6.i1.77.

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Unsworth, A., M. J. Pearcy, E. F. T. White e G. White. "Frictional Properties of Artificial Hip Joints". Engineering in Medicine 17, n. 3 (luglio 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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Pezzotti, Giuseppe, e Kengo Yamamoto. "Artificial hip joints: The biomaterials challenge". Journal of the Mechanical Behavior of Biomedical Materials 31 (marzo 2014): 3–20. http://dx.doi.org/10.1016/j.jmbbm.2013.06.001.

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4

Shi, Ruimin, Bukang Wang, Jiquan Liu, Zhiwei Yan e Lei Dong. "Influence of Cross-Shear and Contact Pressure on Wear Mechanisms of PEEK and CFR-PEEK in Total Hip Joint Replacements". Lubricants 10, n. 5 (30 aprile 2022): 78. http://dx.doi.org/10.3390/lubricants10050078.

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With the increasing market demand for artificial hip joints, total hip joint replacement has gradually become an effective means of treating a series of hip joint diseases. In order to improve the service life of artificial hip joints, some new artificial hip joint materials, including polyetheretherketone (PEEK) and carbon fiber reinforced polyetheretherketone (CFR-PEEK), have been developed. In this paper, pin-on-plate wear tests under different cross-shear ratios and contact pressures were carried out to study the wear mechanism and worn surface topography of PEEK and CFR-PEEK. The experimental results showed that the wear of PEEK was associated with cross-shear, while CFR-PEEK was not. When the cross-shear ratio was 0.039 and contact pressure was 3.18 MPa, PEEK had poor wear resistance and its wear factor was about eight times that of ultra-high molecular weight polyethylene (UHMWPE). The wear resistance of CFR-PEEK had a significant advantage, since its wear factor was about 30% of that of PEEK. The wear factors of PEEK and CFR-PEEK increased as the contact pressure increased. The arithmetic average of the height amplitude of the surface, Sa, also increased gradually according to the topography of the worn surface. The wear mechanisms of PEEK and CFR-PEEK were scratching, plough cutting, and abrasion Since CFR-PEEK had good wear resistance and insensitivity to cross-shear motion, it is suitable for making artificial hip joints under low contact pressure condition.

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5

Fitzgerald, Robert H. "Infections of Hip Prostheses and Artificial Joints". Infectious Disease Clinics of North America 3, n. 2 (giugno 1989): 329–38. http://dx.doi.org/10.1016/s0891-5520(20)30266-x.

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6

Pearcy, M. J. "A New Generation of Artificial Hip Joints". Engineering in Medicine 17, n. 4 (ottobre 1988): 199–201. http://dx.doi.org/10.1243/emed_jour_1988_017_049_02.

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7

COHEN, J. "Wear of polyethylene in artificial hip joints". Journal of Bone and Joint Surgery. British volume 81-B, n. 1 (gennaio 1999): 179. http://dx.doi.org/10.1302/0301-620x.81b1.0810179b.

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8

Weiss, Cornelius, Arne Hothan, Michael Morlock e Norbert Hoffmann. "Friction-Induced Vibration of Artificial Hip Joints". GAMM-Mitteilungen 32, n. 2 (dicembre 2009): 193–204. http://dx.doi.org/10.1002/gamm.200910016.

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9

Unsworth, A., M. J. Pearcy, E. F. T. White e G. White. "Soft layer lubrication of artificial hip joints". Journal of Synthetic Lubrication 5, n. 1 (aprile 1988): 55–72. http://dx.doi.org/10.1002/jsl.3000050105.

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10

Ilincic, S., N. Tungkunagorn, A. Vernes, G. Vorlaufer, P. A. Fotiu e F. Franek. "Finite and boundary element method contact mechanics on rough, artificial hip joints". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 225, n. 11 (26 settembre 2011): 1081–91. http://dx.doi.org/10.1177/1350650111406776.

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An extremely small roughness of constant height magnitude is considered on the femoral head of an artificial hip joint in order to determine the consequences of various regular shapes and clearances on the mechanical performance of this hip prosthesis via a properly coupled finite and boundary element method. In addition, different material combinations typical for widely used hard-on-hard and hard-on-soft hip joint replacements are also taken into account. By analysing the calculated pressure distribution and contact area between the femoral head and the acetabular cup in frictionless dry contact irrespective of material pairings in hip joints, it is shown that both the wavelength of roughness and the clearance significantly affect these mechanical quantities and accordingly too loose or too tight hip implants have to be avoided. Finally, in terms of all numerical findings a suitable optimal design of hip implants is also discussed.

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11

Pezzotti, Giuseppe, Ian C. Clarke, C. Jobe, T. Donaldson, Kengo Yamamoto, Toshiyuki Tateiwa, T. Kumakura, R. Tsukamoto e Junji Ikeda. "Confocal Raman Spectroscopic Analysis of Ceramic Hip Joints". Key Engineering Materials 309-311 (maggio 2006): 1211–14. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.1211.

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A survey of confocal Raman/fluorescence microprobe spectroscopic techniques is presented with emphasis placed on surface analysis of artificial hip joints. Suitable instrumental configurations are first explained in some details in order to describe the versatility of the spectroscopic microprobes to biomedical materials analyses. Then, these notions, which represent the foundation for structural and mechanical analyses of joint surfaces, are applied to selected cases of paramount importance in hip arthroplasty.

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12

Yao, J. Q., T. V. Parry, A. Unsworth e J. L. Cunningham. "Contact Mechanics of Soft Layer Artificial Hip Joints: Part 2: Application to Joint Design". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 208, n. 4 (dicembre 1994): 206–15. http://dx.doi.org/10.1243/pime_proc_1994_208_290_02.

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In this paper, the general solutions previously obtained for the contact mechanics of a soft layer artificial hip joint have been applied to the design of such joints. In particular, simple power-law design formulae have been generated for the prediction of the contact radius and the maximum Tresca shear stress within the elastomeric layer, when the aspect ratio varied from 1 to 20 (which covered the entire range of the aspect ratio for soft layer artificial hip joints). The effects of the layer thickness, Young's modulus of the layer and the equivalent radius of the joint upon the contact area and the maximum Tresca shear stress have all been examined for physiological loading conditions which would be experienced by hip joint prostheses in the body. Furthermore, the shear strain field was calculated so that the level of strain expected for such joints under physiological loading conditions can be estimated. With these data, relevant fatigue tests can be devised to assess the long-term performance of any particular design of soft layer hip joint. Finally, the effect of the friction between articular surfaces upon the stress field within soft layers has been examined using a newly developed asymptotic analytical theory. It was shown that, for a low coefficient of friction, the maximum Tresca shear stress occurred at layer-substrate bonding interface. With an increase in the coefficient of friction, however, the maximum Tresca shear stress increased its magnitude and moved towards the centre of the contact area along the articular surface.

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13

Tang, Gang, Hong Jiang Yang, Dao Fang Chang, Dong Mei Wang e Gao Feng Wei. "Human Kinematic Characteristics during Stair Descent". Applied Mechanics and Materials 155-156 (febbraio 2012): 545–49. http://dx.doi.org/10.4028/www.scientific.net/amm.155-156.545.

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To design and manufacture better artificial joints, it is necessary to obtain the motion range of lower limb statistically. General Staircase as an experimental device had been designed; motion capture system and plantar force measurement system were used to establish a systematic measurement method during stairs descent. The variation and range of hip, knee and ankle joints of 40 samples along different directions in a cycle have been calculated. During stair decent, motion range of hip, knee and ankle joints reach maximum in the sagittal plane and are larger comparing to joint motion range in walking and jogging.

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14

Singh, Ranjeet Kumar, e Swati Gangwar. "An assessment of biomaterials for hip joint replacement". International Journal of Engineering, Science and Technology 13, n. 1 (8 luglio 2021): 25–31. http://dx.doi.org/10.4314/ijest.v13i1.4s.

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Hip replacement is a surgical process where natural hip joints are replaced by artificial hip joint that helps the human being for getting better lifestyle by reduction in the unavoidable pain and better leg movement. The selection of material and durability of the hip joint replacement are serious significance for the implantation, because it determines how load is transferred through the stem. In the selection of materials, various problems related to hip joint replacement are found like adverse tissue reaction, allergic reaction, wear and corrosion resistance etc. To overcome this problem one has to create different new biomaterial. This review gives brief description about the different biomaterial used for hip joint replacement.

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15

Takadama, Hiroaki, e Mineo Mizuno. "A Simulated Synovial Fluid for Wear Characterization of Artificial Hip Joints by a Hip Joint Simulator". Key Engineering Materials 309-311 (maggio 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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Triyono, Joko, Aditya Rio Prabowo e Jung Min Sohn. "Investigation of Meshing Strategy on Mechanical Behaviour of Hip Stem Implant Design Using FEA". Open Engineering 10, n. 1 (23 agosto 2020): 769–75. http://dx.doi.org/10.1515/eng-2020-0087.

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AbstractHip joint is an important human joints system. The damaged hip joints need to be replaced with artificial hip joints. The Study of the hip joint is very costly therefore another calculation method is demanded to produce good result in acceptable time and cost. Considering this problem, a series of study to assess hip joint performance is conducted using numerical approach. Important parameter for example applied materials are used in the modelling by idealizing Ti-6Al-4V compared to SS 316 L, and stemlengthwas chosen to be 128 mm. ANSYS software was used to analyze models, and designed element size variations were set to be in range 1 to 2.5 mm. The magnitude of force was placed on the femoral head with an angle of 16∘C from the vertical axis. Results showed that SS 316 L material has smaller deformation than Ti material. Whereas Central Processing (CP) time decreases in increasing element size for both materials. In addition, more variations in mesh size are needed to get more accurate convergent results.

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JIN, Zhongmin, Sophie WILLIAMS, Joanne TIPPER, Eileen INGHAM e John FISHER. "Tribology of Hip Joints from Natural Hip Joints, Cartilage Substitution, Artificial Replacements to Cartilage Tissue Engineering". Journal of Biomechanical Science and Engineering 1, n. 1 (2006): 69–81. http://dx.doi.org/10.1299/jbse.1.69.

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18

Nakanishi, Takefumi, Kunihide Shikata, Yu Cong Wang, Mikio Iwamoto e Makoto Kondo. "The Characteristics of the New Ceramic Material for Artificial Joints". Key Engineering Materials 309-311 (maggio 2006): 1235–38. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.1235.

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A new zirconia-toughened alumina ceramic (JMM-ZTA) for a ceramic-on-ceramic hip replacement has been developed. The JMM-ZTA has a fracture toughness superior to zirconia, and the JMM-ZTA/JMM-ZTA combination has superior wear-resistant performance to alumina/alumina. Moreover, the JMM-ZTA shows an excellent crystalline phase stability. Therefore, the JMM-ZTA is believed to be useful for artificial hip prostheses.

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19

Auger, D. D., D. Dowson, J. Fisher e Z.-M. Jin. "Friction and Lubrication in Cushion Form Bearings for Artificial Hip Joints". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 207, n. 1 (marzo 1993): 25–33. http://dx.doi.org/10.1243/pime_proc_1993_207_265_02.

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Two hip joint prostheses were designed and constructed to be elastohydrodynamically equivalent producing approximately equal initial contact areas and theoretical film thicknesses. One was made from conventional UHMWPE (ultra-high molecular weight polyethylene) and the other was a cushion component which had a low modulus layer introduced into the joint space. Friction measurements were carried out on a pendulum simulator apparatus and the two joints were compared. In addition the experimental results were compared with theoretical values of friction predicted from elastohydrodynamic lubrication theory. Values for the friction factor at peak load and peak velocity in the cushion cup (0.003–0.009) were much lower than in the UHMWPE cup (0.017–0.042). The low friction values in the cushion cup are consistent with fluid film lubrication in the contact with the thin lubricating film being preserved by microelastohydrodynamic action.

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20

Yao, J. Q. "Contact Mechanics of Soft Layer Artificial Hip Joints: Part 1: General Solutions". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 208, n. 4 (dicembre 1994): 195–205. http://dx.doi.org/10.1243/pime_proc_1994_208_289_02.

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Unlike natural synovial joints, which are lubricated with a full fluid film lubrication mechanism, conventional artificial hip joints are lubricated with a mixed lubrication mechanism. Recently, however, a new generation of artificial hip joints employing compliant layers to mimic the compliance of articular cartilage in natural synovial joints have been developed to provide fluid film lubrication in these joints. While satisfactory lubrication can be achieved by employing soft layers, compliant thin layers are susceptible to the debonding between the soft layer and its stiffer substrate and long-term mechanical fatigue failure. Stress analyses for different designs of such joints are therefore important. In the present paper, the circular contact between a rigid sphere and an elastomeric layer bonded on to a rigid substrate has been analysed with a novel semi-analytical approach. The detailed contact parameters (the contact radius, the maximum surface deformation, the contact pressure and the contact stress inside the layer) have been examined for a wide range of aspect ratios (0 ≤ a/ht ≤ 100).

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21

ZHANG, Lei-Lei, Tao HU, He-Jun LI, Jin-Hua LU, Xue-Tao SHEN, Wei-Feng CAO e Bin WANG. "Wear Particles of Carbon/Carbon Composite Artificial Hip Joints". Journal of Inorganic Materials 25, n. 4 (5 maggio 2010): 349–53. http://dx.doi.org/10.3724/sp.j.1077.2010.00349.

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22

NARITA, Hirohisa, Kakeru HARUSAWA, Makoto YAGIHASHI e Hideo FUJIMOTO. "521 A Wear Prediction System for Artificial Hip Joints". Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2008.21 (2009): 225–26. http://dx.doi.org/10.1299/jsmebio.2008.21.225.

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23

Jin, Z. M. "Theoretical studies of elastohydrodynamic lubrication of artificial hip joints". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 220, n. 8 (agosto 2006): 719–27. http://dx.doi.org/10.1243/13506501jet144.

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24

Jangid, Vivek, Abhishek Kumar Singh e 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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25

Unsworth, A., R. M. Hall, I. C. Burgess, B. M. Wroblewski, R. M. Streicher e M. Semlitsch. "Frictional resistance of new and explanted artificial hip joints". Wear 190, n. 2 (dicembre 1995): 226–31. http://dx.doi.org/10.1016/0043-1648(95)06653-5.

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26

Zhang, Xingen, Gang Shi, Xianjie Sun, Wei Zheng, Xueping Lin e Guiqian Chen. "Factors Influencing the Outcomes of Artificial Hip Replacements". Cells Tissues Organs 206, n. 4-5 (2018): 254–62. http://dx.doi.org/10.1159/000500518.

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Hip replacement is one of the most successful surgeries in the clinic for the removal of painful joints. Hip osteoarthritis and femoral head necrosis are the 2 main reasons for hip replacement. Several factors are associated with the outcomes of surgery. Nonsurgical factors include gender, age, body mass index, prosthetic material, and risk factors. Surgical factors are anesthesia, postoperative complications, and rehabilitation. Considering the increasing demand for hip arthroplasty and the rise in the number of revision operations, it is imperative to understand factor-related progress and how modifications of these factors promotes recovery following hip replacement. In this review, we first summarize recent findings regarding crucial factors that influence the outcomes of artificial hip replacement surgery. These findings not only show the time-specific effect for the treatment and recovery from hip arthroplasty in the clinic, but also provide suitable choices for different individuals for clinicians to consider. This, in turn, will help to develop the best possible postoperative program for specific patients.

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Chen, Shibiao, Gang Cheng e Yusong Pang. "Dynamic Analysis and Trajectory Tracking Control for a Parallel Manipulator with Joint Friction". Applied Sciences 12, n. 13 (1 luglio 2022): 6682. http://dx.doi.org/10.3390/app12136682.

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To overcome the bearing capacity deficiencies of traditional serial hip joint simulators, complex trajectory simulation, among others, as well as a parallel manipulator with two pairs of artificial hip joints and two moving platforms are proposed. The movements and driving forces of the parallel manipulator under the required motion and loading are studied to provide a basis for further research. In this study, the modeling and analysis of inverse kinematics and dynamics for a parallel manipulator with joint friction are derived. In the inverse kinematic model, kinematic relationships between the linear module slider and the moving platform are established, and expressions for the slider are deduced. Subsequently, by analyzing the frictional forces of the artificial hip joint and thrust ball bearing, a rigid body dynamics model of the parallel manipulator with joint friction is established, which is subsequently decomposed into four driving torques associated with the moving platform, joint lever, slider, and screw. Finally, the difference in the kinematic performance between the two moving platforms is analyzed using numerical simulations and experiments, and the accuracy of the established model is verified.

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Wang, F. C., e Z. M. Jin. "Elastohydrodynamic Lubrication Modeling of Artificial Hip Joints Under Steady-State Conditions". Journal of Tribology 127, n. 4 (22 marzo 2005): 729–39. http://dx.doi.org/10.1115/1.1924460.

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A general steady-state elastohydrodynamic lubrication model was developed for artificial hip joints, with particular reference to the effect of the anatomical position of the cup and the three-dimensional physiological loading and motion experienced during walking. Appropriate spherical coordinates and mesh grids were employed to facilitate the numerical solution. A specific hip implant employing an ultrahigh molecular-weight polyethylene acetabular cup against a metallic femoral head was chosen to demonstrate the general applicability of the lubrication model and the effects of both the cup inclination angle and the combined flexion-extension and internal-external rotation on the lubrication were analyzed.

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OTSUKA, Kouichi, Yoshitaka NAKANISHI e Hidehiko HIGAKI. "Influence of standing phase on wear of artificial hip joints". Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2002.14 (2002): 71–72. http://dx.doi.org/10.1299/jsmebio.2002.14.71.

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Mattei, L., F. Di Puccio, B. Piccigallo e E. Ciulli. "Lubrication and wear modelling of artificial hip joints: A review". Tribology International 44, n. 5 (maggio 2011): 532–49. http://dx.doi.org/10.1016/j.triboint.2010.06.010.

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Dowson, D., J. Fisher, Z. M. Jin, D. D. Auger e B. Jobbins. "Design Considerations for Cushion Form Bearings in Artificial Hip Joints". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 205, n. 2 (giugno 1991): 59–68. http://dx.doi.org/10.1243/pime_proc_1991_205_269_02.

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Maehara, Katsuhiko, Kenji Doi, Tomiharu Matsushita e Yoshio Sasaki. "Application of Vanadium-Free Titanium Alloys to Artificial Hip Joints". MATERIALS TRANSACTIONS 43, n. 12 (2002): 2936–42. http://dx.doi.org/10.2320/matertrans.43.2936.

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Scholes, S. C., A. Unsworth, J. M. Blamey, I. C. Burges, E. Jones e N. Smith. "Design aspects of compliant, soft layer bearings for an experimental hip prosthesis". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 219, n. 2 (1 febbraio 2005): 79–87. http://dx.doi.org/10.1243/095441105x9318.

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Abstract (sommario):

Currently, an artificial hip joint can be expected to last, on average, in excess of 15 years with failure due, in the majority of cases, to late aseptic loosening of the acetabular component. A realistic alternative to the problem of wear in conventional joints is the introduction of bearing surfaces that exhibit low wear and operate in the full fluid-film lubrication regime. Contact analyses and friction tests were performed on compliant layer joints (metal-on-polyurethane) and the design of a prototype ovine arthroplasty model was investigated. When optimized, these components have been shown to achieve full fluid-film lubrication.

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Oberbach, Thomas, Sabine Begand e Christian Kaddick. "Surface Resistance of Dispersion Ceramics against Third Body Abrasion". Key Engineering Materials 396-398 (ottobre 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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Tipper, J. L., A. Hatton, J. E. Nevelos, E. Ingham, C. Doyle, R. Streicher, A. B. Nevelos e J. Fisher. "Alumina–alumina artificial hip joints. Part II: Characterisation of the wear debris from in vitro hip joint simulations". Biomaterials 23, n. 16 (agosto 2002): 3441–48. http://dx.doi.org/10.1016/s0142-9612(02)00048-0.

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Malakhov, O. A., A. K. Morozov, E. V. Ogarev e I. A. Kosovo. "Development of the hip joint in children and adolescents (experimental anatomical and radiological study)". N.N. Priorov Journal of Traumatology and Orthopedics 9, n. 3 (2 febbraio 2022): 70–75. http://dx.doi.org/10.17816/vto99952.

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Forty1 eight cadaveric hip joints from humans aged 0 to 18 years were examined to study the process of the joint formation. Polypositional radiologic and CT examinations with and without application of various techniques of artificial contrast were conducted as the first step of the study. Data obtained enabled to define more precisely the dynamics of anatomical changes during the hip joint growth, to detect the method of choice for their diagnosis and the alternative method of radiologic examination. All that is of great importance for the early detection of the pathologic changes as well as for the elaboration of diagnostic and curative management.

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TANABE, Y., T. UCHIYAMA, H. YAMAOKA e H. OHASHI. "LOAD TRANSMISSION THROUGH ARTIFICIAL HIP JOINTS DUE TO STRESS WAVE LOADING". International Journal of Modern Physics B 22, n. 09n11 (30 aprile 2008): 1789–94. http://dx.doi.org/10.1142/s0217979208047420.

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Since wear of the polyethylene (Ultra High Molecular Weight Polyethylene or UHMWPE) acetabular cup is considered to be the main cause of loosening of the artificial hip joint, the cross-linked UHMWPE with high durability to wear has been developed. This paper deals with impact load transmission through the complex of an artificial hip joint consisting of a UHMWPE acetabular cup (or liner), a metallic femoral head and stem. Impact compressive tests on the complex were performed using the split-Hopkinson pressure bar apparatus. To investigate the effects of material (conventional or cross-linked UHMWPE), size and setting angle of the liner, and test temperature on force transmission, the impact load transmission ratio (ILTR) was experimentally determined. The ILTR decreased with an increase of the setting angle independent of material and size of the liner, and test temperature. The ILTR values at 37°C were larger than those at 24 °C and 60°C. The ILTR also appeared to be affected by the type of material as well as size of the liner.

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Kalayarasan, M., V. Prabhu Raja, V. Nithin, S. Vivinkumar e M. Vishwaanth. "Comparative Study of Wear Behavior of Multilayer Coatings for Human Hip Prosthesis". Applied Mechanics and Materials 787 (agosto 2015): 528–33. http://dx.doi.org/10.4028/www.scientific.net/amm.787.528.

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Artificial hip joints have been implanted throughout the world into patients suffering from disabling hip joint disease, to restore their painless joint function. This means replacing the femoral head and acetabular socket with artificial prosthetic components. In order to obtain artificial implants with enhanced physical, chemical, mechanical, biological and tribological properties resulting in the accelerated self-adaptation of human body and long term performance, it is necessary to combine the advantages of materials with various properties; biocompatibility, bioactivity, excellent corrosion resistance, high fatigue and tensile strength, low modulus of elasticity, coefficient of friction, and high wear resistance. The present work focuses on investigating the wear rate of multi-layer coatings for different combinations in order to reduce the wear rate of the prosthesis. Three different combinations of multilayer coating were deposited by plasma arc spraying technique on titanium. It was found that the multi-layer coating consists of Alumina as a primary coating and Zirconia as the secondary coating provides lower wear rate and higher hardness compared to other combinations which would give optimal performance and thereby increasing its longevity.

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Yang, Jianyu, Guanchao Li, Xiaofei Zhao e Hualong Xie. "Research on Joint-Angle Prediction Based on Artificial Neural Network for Above-Knee Amputees". Sensors 21, n. 21 (29 ottobre 2021): 7199. http://dx.doi.org/10.3390/s21217199.

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In the current study, our research group proposed an asymmetric lower extremity exoskeleton to enable above-knee amputees to walk with a load. Due to the absence of shank and foot, the knee and ankle joint at the amputation side of the exoskeleton lack tracking targets, so it is difficult to realize the function of assisted walking when going up and downstairs. Currently, the use of lower-limb electromyography to predict the angles of lower limb joints has achieved remarkable results. However, the prediction effect was poor when only using electromyography from the thigh. Therefore, this paper introduces hip-angle and plantar pressure signals for improving prediction effect and puts forward a joint prediction method of knee- and ankle-joint angles by electromyography of the thigh, hip-joint angle, and plantar pressure signals. The generalized regression neural network optimized by the golden section method is used to predict the joint angles. Finally, the parameters (the maximum error, the Root-Mean-Square error (RMSE), and correlation coefficient (γ)) were calculated to verify the feasibility of the prediction method.

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LI, He-Jun, Lei-Lei ZHANG, Jin-Hua LU, Ke-Zhi LI, Qian-Gang FU, Xue-Ni ZHAO e Sheng CAO. "Wear Mechanism of Biomedical Carbon/Carbon Composites for Artificial Hip Joints". Journal of Inorganic Materials 25, n. 9 (30 agosto 2010): 999–1002. http://dx.doi.org/10.3724/sp.j.1077.2010.10144.

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41

SUN, ZHUO YAN, Kazuyoshi ISHIDA e Katsuzo OKADA. "213 A Fundamental Study on Sliding Friction of Artificial Hip Joints". Proceedings of Conference of Kanto Branch 2001.7 (2001): 363–64. http://dx.doi.org/10.1299/jsmekanto.2001.7.363.

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KENMOTSU, Masashi, Kazuyoshi ISHIDA e Katsuzo OKADA. "428 The effect of lubricants on wear for artificial hip joints." Proceedings of Yamanashi District Conference 2001 (2001): 139–40. http://dx.doi.org/10.1299/jsmeyamanashi.2001.139.

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43

Wang, F., C. Brockett, S. Williams, Z. Jin e J. Fisher. "Friction and lubrication modelling of metal-on-metal artificial hip joints". Journal of Biomechanics 39 (gennaio 2006): S139. http://dx.doi.org/10.1016/s0021-9290(06)83461-5.

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44

Wilches, L. V., J. A. Uribe e A. Toro. "Wear of materials used for artificial joints in total hip replacements". Wear 265, n. 1-2 (giugno 2008): 143–49. http://dx.doi.org/10.1016/j.wear.2007.09.010.

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Kaulgud, A., A. Crugnola, T. Vasilos e C. Sung. "Microstructural Characterization of a New Polytetrafluoroethylene for Artificial Hip Prosthesis". Microscopy and Microanalysis 6, S2 (agosto 2000): 1124–25. http://dx.doi.org/10.1017/s1431927600038113.

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All joints in the human body are subject to destruction by disease and trauma. Although the modem concept of joint replacements dates back to 1800's, polymeric material were not utilized till 1940's [1]. Early experiments were conducted with polymethacrylate and polytetrafluoroethylene. The results were disappointing with the polymeric material either quick fracturing or wearing at an extreme rapid rate. Microstructures were not well investigated as a function of processing conditions.The goal of this research is to eliminate the presence of oxygen within the components during its processing operations, which is responsible for early failure of polytetrafluoroethylene. One approach to eliminate or reduce the amount of oxygen would be processing the PTFE resin in vacuum conditions. This research is aimed towards investigating the microstructure of PTFE when processed under vacuum conditions using SEM and TEM along with EDXS.The fabricated PTFE billet samples were received from Dewal Industries, NJ and the PTFE components in vacuum conditions, processed at University of Massachusetts Lowell (UML) were studied using microscopic techniques.

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Priyana Soemardi, Tresna, Agri Suwandi, Cholid Badri, Anwar Soefi Ibrahim, Sastra Kusuma Wijaya e Januar Parlaungan Siregar. "Development of Total Hip Joint Replacement Prostheses Made by Local Material: An Introduction". E3S Web of Conferences 130 (2019): 01032. http://dx.doi.org/10.1051/e3sconf/201913001032.

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Total Hip Joint Replacement Surgery is the procedure of surgical removal of cartilage in the hip joints damaged by disease osteoarthritis to replaced with artificial components. Total Hip Joint Replacement has been indicated to relieve pain in the pelvis due to degenerative joint disease. In Indonesia, this procedure has been practised, but due to the cost of expensive products resulting in limited only to upper classify patients. The high prices caused by importing prostheses products, the technological capabilities and the difficulty to meet the standards of medical devices. The regulation of the Minister of Health of the Republic of Indonesia Number 52, 2016 for standard rates in organising health services Health Assurance Program, explained that the action of these operations entered into the insurance claims BPJS program, but not for the prostheses. This paper discusses the introduction of the development of the hip joint prostheses made from a local material that’s SS 316L, PEEK and Ceramic Dental Stone. The result of this development is the product of the hip joint prostheses has a reasonable price with good quality so that it can become affordable for middle to lower patients.

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Aota, Shigeo, Shin-ichi Kikuchi, Hironori Ohashi, Naoko Kitano, Michiyuki Hakozaki e Shin-ichi Konno. "Soft tissue reinforcement with a Leeds-Keio artificial ligament in revision surgery for dislocated total hip arthroplasty". HIP International 28, n. 3 (16 ottobre 2017): 324–29. http://dx.doi.org/10.5301/hipint.5000573.

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Introduction: Since dislocation after total hip arthroplasty (THA) greatly diminishes patient’s quality of life, the THA frequently needs revision. However, it is common for the dislocation not to heal even after reconstruction, but rather to become intractable. Methods: The 17 patients with dislocated THA, mean age of 71 years (range 51-87 years), who underwent a revision THA together with soft tissue reinforcement with a Leeds-Keio (LK) ligament were enrolled. The purposes of reinforcement with LK ligament were to restrict the internal rotation of the hip joint, and to encourage the formation of fibrous tissue in the posterior acetabular wall to stabilise the femoral head. We determined the success rate of surgical treatment for dislocation, the Harris Hip Score (HHS), a factor of recurrent dislocation. Results: There was no recurrent dislocation in 82% of the cases (14 joints) during the mean postoperative follow-up period of 63.5 months (15-96 months). The HHS was 82 ± 18 points preoperatively and 82 ± 14 points postoperatively. Recurrent dislocation after this surgical procedure occurred in 2 hips with breakage of the LK ligaments, and intracapsular dislocation in 1 hip with loosening of the LK ligament. Conclusions: Although the risk of recurrent dislocation still exists with this procedure, when performed to provide reinforcement with an LK ligament for dislocated THA it may be useful in intractable cases with soft tissue defects around the hip joint.

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Ingham, E., J. Fisher e M. H. Stone. "Wear of Historical Polyethylenes in Hip Prostheses. Biomechanical Success and a Biological Failure". HIP International 13, n. 2_suppl (gennaio 2003): 17–27. http://dx.doi.org/10.1177/112070000301302s05.

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Polyethylene wear debris induced osteolysis is a major cause of failure in artificial hip joints. Sub micrometre size particles are taken up by macrophages which are stimulated to release osteolytic cytokines such as TNFα. This leads to bone resorption, loosening and failure. In vitro cell culture studies have shown particles in the size range 0.1 to 1 micrometre to be at least six times more reactive than larger particles. Studies of historically used gamma irradiated in air polyethylene show increased wear rate with damaged femoral heads and with aged and oxidised polyethylene. The aged and oxidised polyethylene also produced a greater percentage of smaller particles leading to increased osteolytic potential. Combined tribological and biological simulation models have been developed for pre-clinical assessment of osteolytic potential of artificial hip joints.

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Fouly, Ahmed, Ibrahim A. Alnaser, Abdulaziz K. Assaifan e Hany S. Abdo. "Evaluating the Performance of 3D-Printed PLA Reinforced with Date Pit Particles for Its Suitability as an Acetabular Liner in Artificial Hip Joints". Polymers 14, n. 16 (15 agosto 2022): 3321. http://dx.doi.org/10.3390/polym14163321.

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Off-the-shelf hip joints are considered essential parts in rehabilitation medicine that can help the disabled. However, the failure of the materials used in such joints can cause individual discomfort. In support of the various motor conditions of the influenced individuals, the aim of the current research is to develop a new composite that can be used as an acetabular liner inside the hip joint. Polylactic acid (PLA) can provide the advantage of design flexibility owing to its well-known applicability as a 3D printed material. However, using PLA as an acetabular liner is subject to limitations concerning mechanical properties. We developed a complete production process of a natural filler, i.e., date pits. Then, the PLA and date pit particles were extruded for homogenous mixing, producing a composite filament that can be used in 3D printing. Date pit particles with loading fractions of 0, 2, 4, 6, 8, and 10 wt.% are dispersed in the PLA. The thermal, physical, and mechanical properties of the PLA–date pit composites were estimated experimentally. The incorporation of date pit particles into PLA enhanced the compressive strength and stiffness but resulted in a reduction in the elongation and toughness. A finite element model (FEM) for hip joints was constructed, and the contact stresses on the surface of the acetabular liner were evaluated. The FEM results showed an enhancement in the composite load carrying capacity, in agreement with the experimental results.

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Fattarizka, Almira Dea, e Hernastiti Sedya Utami. "Case Study: Antero-Posterior Projection of Pelvis Radiographic Examination Techniques in the Diagnosis of Hemiarthroplasty". Proceedings Series on Health & Medical Sciences 2 (26 gennaio 2022): 133–38. http://dx.doi.org/10.30595/pshms.v2i.235.

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Hemiarthroplasty is a surgical procedure to replace half of the hip joint with a prosthesis or artificial joint. The radiology procedure for the Hemiarthroplasty at Orthopaedic Hospital Purwokerto uses Antero-posterior projection of the pelvis. This projection is different from the routine projection, namely the Unilateral Antero-posterior Hip Projection. The purpose of this study is to determine the procedure for radiographic examination in cases of Hemiarthroplasty and to find out the reasons for using the Antero-posterior Pelvis projection to establish the patient's diagnosis. This type of research was qualitative with a case study approach. Data collection conducted in December 2020 at the Radiology Installation of the Orthopaedic Hospital Purwokerto, using the methods of observation, documentation, and interviews with radiographers and radiologists. Data analysis performed with primary data taken from one patient with Hemiarthroplasty. The patient has a history of fracture (broken bone) in the right side of the femoral neck before hemiarthroplasty surgery. The results showed that the proper projection for Hemiarthroplasty is the Antero-posterior Pelvis projection. The reasons were to see a comparison between the right and left hip joints and to find if there is a space or distance from the hip joints after the surgery procedure. Radiologists can get needed anatomical information about the pelvis by performing an Antero-posterior projection.

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