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EN
The paper presents results of studies pertaining to evaluation of a quality (compressive strength of mounting the implant within the bone) of mounting the implant mandrel within the osseous tissue for various relevant techniques. The presented results are related to selected techniques of mounting the implant mandrel within a bone. The comparison has been carried out for cement-less mandrels with a smooth mandrel of the endoprosthesis, porous cementless endoprostheses as well as mandrels made of bioactive materials.
PL
W artykule przedstawiono wyniki kompleksowej analizy oraz oceny jakości technologicznej (chropowatości i dokładności wymiarowo-kształtowej) głów endoprotez wykonanych z materiałów ceramicznych. Badane głowy wykonano z dwóch różnych gatunków materiałów, o właściwościach izo- i anizotropowych, które po uzyskaniu pozytywnych wyników badań medycznych będą mogły być zastosowane na implanty stawów.
EN
The paper presents results of thorough analysis and assessment of technological quality (roughness, dimensional and shaping precision) of endoprosthesis heads made of ceramic materials. Tested heads were made of two different kinds of materials with iso- and anisotropic properties. Depending on medical test results, an assessment of each material's suitability for joints, implants will be made.
EN
Most of the mechanical failures in alloplasty are caused by material fatigue. To cut down the risk of it, we can either increase the fatigue resistance of the material or decrease the load strain. All presented numerical calculations allow to draw quality conclusions concerning the influence of some parameters of endoprostheses on the values of stress and strain that are formed in polyethylene inserts.
PL
W pracy przedstawion wpływ oddzielnego i łącznego oddziaływania odkształcenia plastycznego i sterylizacji wiązką elektronów na zmiany w strukturze molekularnej i nadcząstkowej Chirulenu, stosowanego do wytwarzania panewek endoprotez Wellera.Stwierdzone efekty wewnętrznej przebudowy polimeru pozwoliły zinterpretować zmiany twardości, modułu sprężystości i podatności na odkształcenia nietrwałe. Analiza przyczynowo-skutkowa umożliwiła prognozę potencjalnych zachowań biopolimeru podczas eksploatacji implantu w zakresie: możliwości tłumienia obciążeń i wyeliminowania potencjalnych pęknięć panewki oraz intensywności zużycia tribologicznego w czasie ruchu pacjenta.
EN
The paper presents the influence of separable and additive efects of plastic deformation and sterilization by an electron beam on changes in the molecular and supermolecular structure of Chirulen used for the production of Weller endoprostheses acetabular cups. The found effects of a polymer internal structure modyfication allowed to interpretthe changes in hardness, modulus of elasticity and susceptibility to undurable deformation. A cause-effect analysis made it possible to predict potential biopolymer behaviors during implant's service in the range of load damping capability and elimination of possible cup cracking as well as the intensity of tribological wear during patient's movement.
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EN
This paper presents a finite element simulation of an oncology knee-joint endoprosthesis in a various degrees of flexion. The simulation has been made in accordance with an ISO 14243 [1-3]. A model of the knee implant (produces by ProSpon, s.r.o. [4]) consists of following parts: femoral stem, femoral replacement, femoral component, PE bushings, and tibial plateau. Results for four positions of flexion (1.53deg, 8.13deg, 15.31deg and 26.33deg) gave better understanding of strain and stress distribution along the endopros-thesis and pointed out also the most crucial areas requiring the attention. These foundlings are useful for individual design of the knee-joint prosthesis and for further development.
EN
The paper presents Finite Elements Method numerical analysis of strength of friction pairs most often used in hip and knee joints alloplasty. Analytic solutions are to indicate and define the areas where damages or premature wear of cooperating elements may occur. Analytical-experimental research states complete and thorough analysis. Accurate technical simulation of the joints of the human motor system, is difficult to conduct due to high level of complexity of human bio-bearings. All attempts to simulate the work of human joints, lead only to an approximate reflection of real human joint motion. To properly face the above problems, along with numerical analysis, there have been conducted empirical tests on the simulator of knee joint endoprosthesis.
EN
The paper presents mathematic-statistic methods defining the influence of stress on ceramic elements’ durability of hip and knee joints endoprostheses. The tests were conducted with Finite Elements Method in the ADINA System. The obtained results state the influence of load on the values of durability and stress, that get formed in ceramic parts of joints, and help to detect and solve technical problems and thus, counteract the subsequent effects resulting from premature wear of endoprosthesis elements. The paper emphasizes necessity of discovering new materials, that will be bio-compliant and wear resistant. Although ceramic materials like Al2O3, ZrO2, are brittle and less resistant to load than metallic implants, their improving mechanical parameters (excellent tribological properties), make them becoming new standard in biomaterials for clinical use. That opens new possibilities especially for hip or knee joints alloplasty.
EN
The paper presents results of the preliminary structural analysis of model of the endoprosthesis of the knee joint. Basics of anatomy and biomechanics of the knee joint were introduced. Based on data from computed tomography, the model of knee joint was constructed. The prototype of the endoprosthesis of the knee joint was designed. After determining physical properties of structural materials, the Finite Elements Analysis of the model was conducted under various load conditions. Finally the results of analysis are presented.
EN
The paper presents results of the preliminary structural analysis of model of the endoprosthesis of the hip joint. Basics of anatomy and biomechanical analysis of the hip joint were introduced. Based on data from atlas of human anatomy and medical imaging, the prototype of endoprosthesis was modelled using Solid Edge ST8 software. After determining physical properties of structural materials, the Finite Elements Analysis of the model was conducted using in SolidWorks software under various load conditions. Finally the results of analysis are presented.
PL
Celem pracy była ocena przydatności teorii zbiorów przybliżonych w analizie zużycia endoprotez. W pracy wyodrębnić można dwie zasadnicze części: w pierwszej opisano badania tribologiczne endoprotez stawu biodrowego, natomiast w drugiej dokonano analizy wyników tych badań, wykorzystując metodę generowania reguł decyzyjnych w oparciu o teorię zbiorów przybliżonych. W efekcie stwierdzono, że wygenerowane reguły decyzyjne nie są sprzeczne z aktualnym stanem wiedzy, a zaproponowana metoda analizy może być przydatna w analizie tego rodzaju zagadnień.
EN
The aim of the study was to evaluate the usefulness of rough set theory in the analysis of endoprosthesis wear. In the article, two main parts can be distinguished: the first describes the tribological study of hip endoprosthesis, while the second analyses the results of these tests using the method of generating decision rules based on rough set theory. There were generated two sets of decision rules describing the impact of roughness, friction, wear and the angle of the prosthesis head on the chromium, and cobalt ions emission. As a result, it was found that the generated decision rules are consistent with the current state of knowledge, and the proposed method of analysis may be useful in the analysis of such issues.
11
Content available remote Selected Mechanical Properties of the Endoprosthesis-Bone Joint
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EN
One presented results of experimental studies on an implant-bone joint. There is described a way of conducting experimental studies on samples that had been prepared beforehand, as well as a way of preparing the samples using animal bone tissues. On the basis of the obtained results, one determined a reaction of the bone tissue in a function of the applied load, resulted by the mandrel mounted within the tissue. The experiment revealed characteristic three phases of the behavior of the bone tissue affected by the mounted mandrel.
EN
The key requirement for the modern endoprosthesis is high durability of the friction components, which results in long and trouble-free operation in the human body. The durability of currently used endoprosthesis is often limited by tribological wear processes of friction components (e.g. between the head and the acetabular component in a hip joint endoprosthesis) [8, 19, 23, 24]. In order to compare the tribological wear, tribological tests were carried out by means of tribometer on friction pairs of the following composition: implantation steel 316 LVM/PE-UHMW and titanium alloy Ti13Nb13Zr/PE-UHMW. Determining of the friction coefficient, measured profiles of surface roughness and microscopic observation allowed to evaluate the abrasive wear of the tested biomaterials.
EN
The ceramic parameters are based on Weibull weakest link theory. Paper presents the results of the calculation of the ceramic material parameters (m, σU, σo) from the destruction test of the set of 40 pieces of the total hip joint endoprosthesis ceramic head.
EN
ObjectivesThe study evaluated the professional activity of patients after a total cementless hip replacement surgery performed at the age of ≤30 years.Material and MethodsThe study group comprised 87 patients, with 95 total cementless hip replacements. The mean age was 25.7 years. The youngest patient was 17 years old, and the oldest 30 years old. The mean length of observation was 20.1 years, ranging 5–33 years. All patients underwent clinical and radiological evaluations before the surgery, and again in the third, sixth and twelfth months after the surgery. Further follow-up visits were performed every year. The tests were scored according to the Merle d’Aubigné and Postel (MAP) classification, as recommended by the Polish Society of Orthopaedics and Traumatology. Postoperative radiographs were used to assess the position of the endoprosthesis, and the degree of implant healing in the bone tissue. The data was subjected to statistical analysis.ResultsOf the surveyed group, 67 patients were professionally active before the surgery: 34 were white-collar workers, 29 manual workers, and 4 students or school pupils. The remaining 20 had not worked for many years, and were receiving sickness or disability benefits. An excellent result, according to the Kellgren-Lawrence classification, was noted in 22 cases, a good result in 42 cases, and a satisfactory result in 6 cases. In 25 cases, a poor result was observed. All of the patients professionally active before the surgery returned to work following the procedure. A further analysis found that 15 previously-unemployed patients commenced employment following the procedure. The mean length of the sick leave was 196.2 days, and rehabilitation payments were granted in 5 cases.ConclusionsTotal cementless hip replacement is a valuable method of treating osteoarthritis in young patients. All of the patients who worked before the surgery returned to work in the same position and on the same employment conditions. Most of the previously-unemployed patients commenced employment following the procedure.
EN
The article presents the results of friction wear tests of hip joint endoprostheses. The study comprised tests of endoprostheses, commercially available on the European market, used in total hip arthroplasty. The friction pair was formed by an actual cupacetabular cup made of ultra-high molecular weight polyethylene (PE-UHMW) along with a head having a diameter of 28 mm made of stainless steel FeCrNiMnMoNbN. The friction and wear tests were performed using an SBT 01.2 hip joint simulator of the authors’ own design, which was constructed taking into account the ISO 14242-1 standard. Bovine serum was used as the lubricant. The tests of each friction pair were made up to 5·106cycles of motion. During the tests, simulator operation was interrupted every 5·105 cycles to replace the lubricating liquid, and mass control was performed every 1·106 cycles. Prior to testing, the polyethylene cup was soaked in the lubricant to minimize liquid absorption during the test. Proper preparation of the cup and testing by taking into account a control group weight measurement allowed an accurate determination of the mass loss of the polyethylene cup.
PL
Przedstawiono wyniki badań tarciowo-zużyciowych endoprotez stawu biodrowego. Materiał badany stanowiły endoprotezy komercyjne dostępne na rynku europejskim, stosowane w alloplastyce całkowitej stawu biodrowego. Parę trącą tworzyła panewka wykonana z polietylenu o ultrawysokiej masie cząsteczkowej PE-UHMW wraz z głową o średnicy 28 mm wykonaną ze stali o symbolu producenta SS (FeCrNiMnMoNbN). Badania tarciowo-zużyciowe przeprowadzono przy użyciu symulatora ruchu stawu biodrowego SBT 01.2 własnej konstrukcji, który skonstruowany został w oparciu o normę ISO 14242-1. Jako medium smarujące zastosowano surowicę bydlęcą, która przygotowywana była do testów zgodnie z wytycznymi opisanymi w normie ISO 14242-1. Dla każdej pary trącej zadana liczba cykli ruchu wynosiła 5·106. W trakcie trwania testów, co 5·105 cykli praca symulatora była przerywana celem wymiany cieczy smarującej, a co 1·106 przeprowadzano kontrolę masy próbek. Przed przystąpieniem do testów tarciowo-zużyciowych polietylenowa panewka namaczana była w cieczy smarującej celem zminimalizowania absorpcji cieczy w trakcie trwania testu. Odpowiednie przygotowanie panewek oraz przeprowadzenie testu z uwzględnieniem grupy kontrolnej pozwoliło na określenie zużycia masowego panewek polietylenowych.
EN
This paper contains the results of the load analysis of a modular hip joint endoprosthesis, performed by means of the finite elements method, using Autodesk Simulation Mechanical 2016 software. A geometric model was created based on real solutions using Autodesk Inventor Professional. The obtained results make it possible to indicate the “weak points” of the accepted solution, and thus counteract the subsequent effects resulting from premature wear of endoprosthesis elements.
EN
The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether) glycol (PTMEG), as well as from two different isocyanates 4,4′-methylenebis(cyclohexyl)isocyanate (HMDI) and 4.4′-methylenebis(phenyl isocyanate) (MDI) in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyurethane surface wettability, friction coeffi cient for different couples of the co-working materials such as polyurethane–polyurethane, polyurethane–titanium alloy, polyurethane–alumina, in comparison to commonly used polyethylene–titanium alloy. Shear strength of polyurethane–alumina joint, as well as viscosity of prepolymers were also measured. The values of friction coeffi cient were compared to literature data on commercially available polyurethane with the trade name Pellethane. Polyurethanes obtained are characterized by low abrasive wear and low friction coeffi cient in couple with the titanium alloy, what makes them attractive as possible components of ceramic-polymer endoprosthesis joints.
EN
It can be stated that over the last ten years in the European Union, the number of bone fractures caused by osteoarthritis has increased twofold. More than 100,000 hip or knee joints in total were implanted in Germany during one year. Within ten years, 5% of them have failed by aseptic loosening. The non-invasive determination of friction forces and control of their values during lubrication of cartilage cells on the superficial layer of human joint surfaces before implantation has a significant but not sufficient impact on the observation of the early abrasive wear of the cartilage joint and development of osteoporosis. From this fact was drawn the inspiration for the performed investigations related to the endoprosthesis surface parameters because knowledge of the roughness of prosthesis surfaces and friction forces and their control methods permits provision of a necessary standard deviation of the gap height and finally information about the implantation possibility. This article has been prepared based on the objective of European Project UE Grant IRSES,612593, 2013-2016 to represent the methodology and goal of the idea described in and make a wider discussion possible on this subject for further developments during the realization. To the research methods and materials used in this article realization belong: Rank Taylor Hobson-Talyscan 150 Apparatus implemented by Talymap Expert and Microsoft Excel Computer Program connected with the Mathcad 15 Professional Program and a new semi-analytical methods of probabilistic and statistic prognosis applied for theory of hydrodynamic lubrication of the curvilinear orthogonal surface and coordinates extended to the friction and wear problems of the endoprosthesis surfaces during the exploitation.
EN
The paper presents the numerical analysis of stress occurring in the most wearable parts of knee joint endoprostheses. That applies to the pair: sled - spherical insert. The Finite Elements Method makes it possible to calculate the stress in particular elements of the tested model. The interaction between the two parts of endoprosthesis takes place on a comparatively small contact surface.
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Content available remote Polyurethanes from the crystalline prepolymers resistant to abrasive wear
75%
EN
The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether) glycol (PTMEG), as well as from two different isocyanates 4,4′-methylenebis(cyclohexyl)isocyanate (HMDI) and 4.4′-methylenebis(phenyl isocyanate) (MDI) in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyurethane surface wettability, friction coefficient for different couples of the co-working materials such as polyurethane-polyurethane, polyurethane-titanium alloy, polyurethane-alumina, in comparison to commonly used polyethylene-titanium alloy. Shear strength of polyurethane-alumina joint, as well as viscosity of prepolymers were also measured. The values of friction coefficient were compared to literature data on commercially available polyurethane with the trade name Pellethane. Polyurethanes obtained are characterized by low abrasive wear and low friction coefficient in couple with the titanium alloy, what makes them attractive as possible components of ceramic-polymer endoprosthesis joints.
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