- MeSH
- Cartilage transplantation MeSH
- Endothelium transplantation MeSH
- Glottis physiology transplantation MeSH
- Cochlear Implants MeSH
- Bone Substitutes classification MeSH
- Blood MeSH
- Blood Substitutes therapeutic use MeSH
- Humans MeSH
- Nanoparticles utilization MeSH
- Joint Prosthesis classification MeSH
- Hearing physiology MeSH
- Stem Cell Transplantation utilization MeSH
- Skin Transplantation MeSH
- Corneal Transplantation MeSH
- Skin, Artificial MeSH
- Check Tag
- Humans MeSH
Zavedení umělých kloubních náhrad představuje pro miliony lidí na celém světě převratnou metodu léčby závažných kloubních postižení. Ročně narůstá počet primoimplantací a rostou nároky na životnost kloubních náhrad. S tím se ale také zvyšují nároky na odolnost artikulačních povrchů vůči opotřebení. Nejužívanějším materiálem pro jejich výrobu je stále vysokomolekulární polyetylén (UHMWPE – ultra-high molecular weight polyethylene). Ten byl zaveden do klinické praxe již v 60. letech 20. století. Fyzikálně chemické vlastnosti UHMWPE jsou předmětem mnoha výzkumů, které postupně vedou k jeho vyšší odolnosti vůči otěru při zachování stability vůči oxidativní degradaci.
The introduction of artificial joint replacement constitutes a breakthrough method of treatment for severe joint disease for millions of people worldwide. Annual increase in the number of primary replacement and also increasing demands on the longevity of joint replacements are leading to increased demands on wear resistance of articular surface. Ultra-high molecular weight polyethylene (UHMWPE) is still most commonly used material for the production of articular surface. It was introduced into clinical practice in the 60s of the 20th century. Physical-chemical properties of UHMWPE are subject of many studies. These lead gradually to its improvement in terms of higher wear resistance while maintaining the stability against oxidative degradation. The main objective of this review is to summarize the basic properties of high-molecular weight polyethylene which are important for its use in orthopaedic practice and to explain the possibilities of its modification and sterilization. Knowledge of the latest trends about this material helps to orthopaedic surgeons get oriented in the issues and then to choose for their patients implants with the highest implant longevity.
- Keywords
- vysokomolekulární polyethylen, UHMWPE,
- MeSH
- Ethylene Oxide chemistry MeSH
- Humans MeSH
- Arthroplasty, Replacement, Hip methods MeSH
- Polyethylene * chemistry MeSH
- Joint Prosthesis classification trends MeSH
- Sterilization methods MeSH
- Vitamin E chemistry MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
PURPOSE OF THE STUDY: Each method of sterilisation has some effect on the structure and properties of UHMWPE and thus also on joint replacement longevity. This study was designed to compare, using objective methods of measurement, several kinds of sterilisation and to recommend the one which has the best prospect for making joint replacements last longer. MATERIAL AND METHODS: Two groups of UHMWPE samples were tested. Group 1 included virgin GUR 1020 polyethylene, non-modified and non-sterilised (Meditech, Germany). Group 2 comprised of three sets of samples sterilised with formaldehyde, gamma irradiation and ethylene oxide, respectively. In both groups, physicochemical properties were assessed by infrared spectroscopy (IR), and the oxidation (OI) and trans-vinyl (VI) indices, which show the degree of oxidation of a material, were determined. Free-radical concentrations were measured by the method of electron spin resonance (ESR). The mechanical properties of each sample were studied using small punch tests (SPT) and testing microhardness (MH). Any change in mechanical properties can affect, to various degrees, the quality and longevity of a prosthetic joint. RESULTS: The samples sterilised by gamma irradiation showed higher values of both the OI (0.37) and the VI index (0.038) than the other samples (OI, 0.02 to 0.05 and VI, 0). Also, the free-radical concentration was detectable only in the gamma-sterilised sample. Values obtained for mechanical properties were as follows: peak load in the range of 58.48 N (gamma irradiation) to 59.60 N (ethylene oxide); ultimate load in the range of 46.69 N (gamma irradiation) to 57.50 N (ethylene oxide); ultimate displacement in the range of 4.29 mm (gamma irradiation) to 4.58 mm (virgin polyethylene and formaldehyde); and work to failure in the range of 185.18 mJ (gamma irradiation) to 205.89 mJ (virgin polyethylene). Microhardness values were obtained in the following ranges: 41.2 to 44.6 MPa (virgin polyethylene); 40.2 to 44.1 MPa (formaldehyde); 46.1 to 49.3 MPa (gamma irradiation); and 40.3 to 44.2 MPa (ethylene oxide). DISCUSSION: The samples sterilised with formaldehyde and ethylene oxide have mechanical properties very similar to virgin polyethylene, they are not damaged by oxidation and do not contain free radicals. Owing to these characteristics, the immediate and long-term oxidation stability of the three samples is higher. The sample sterilised by gamma irradiation showed the presence of free radicals and immediate and long-term oxidative degradation. This results in the deterioration of mechanical properties and the growth of crystallinity due to enhanced oxidation and leads to higher polyethylene microhardness. CONCLUSIONS: Sterilisation with gamma irradiation results in oxidative degradation and mechanical property deterioration, which is one of the potential risks of a shorter life span of joint replacements. The use of ethylene oxide or formaldehyde does not change polymer properties nor has any effect on oxidation of materials. Therefore, a longer life expectancy of the joint replacements sterilised with ethylene oxide can be expected. The life span of their joint replacements is a key issue for the patients. Prosthetic joint loosening is painful and the patient often requires re-implantation. A higher number of re-implantations is associated with higher costs for the institution involved and, consequently, for the whole health care system. Although this study basically deals with chemical issues, it informs the surgeon of the latest developments leading to the improvement of implanted materials, which can increase the life expectancy of joint replacements and patients' satisfaction.
- MeSH
- Arthroplasty, Replacement methods MeSH
- Ethylene Oxide pharmacology MeSH
- Formaldehyde pharmacology MeSH
- Humans MeSH
- Polyethylene therapeutic use MeSH
- Joint Prosthesis * adverse effects classification MeSH
- Prosthesis Failure MeSH
- Spectrophotometry, Infrared methods MeSH
- Comparative Effectiveness Research MeSH
- Sterilization methods MeSH
- Materials Testing methods MeSH
- Gamma Rays * MeSH
- Check Tag
- Humans MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
- Comparative Study MeSH
Cíl studie Bikonická závitořezná jamka Zweymüller od svého zavedení na trh v roce 1993 prošla tvarovými úpravami. Na obvodu jamky se snižovaly počty zářezů sloužících pro dokonalé usazení jamky. Pro zvýšené nebezpečí nalomení či rozlomení objímky v místech zářezů se původní počet 8 snížil na 4, poslední inovovaný typ je již bez zářezů. Cílem práce je srovnávající pevnostní analýza původních jamek se zářezy s inovovanými bez zářezů. Materiál Autoři uvádějí přednosti bikonické závitořezné jamky. Popisují materiál objímky i polyetylenové vložky. Zdůvodňují snížení zářezů na obvodu objímky. Hlavní autor udává zkušenosti s implantací téměř 400 bikonů se 4 zářezy v období od března 1996 do prosince 2007. Od ledna 2008 již používá výhradně objímky bez zářezů. Uvádí kazuistiku s rozlomenou jamkou. Metody Pro pevnostní analýzu byl vybrán systém Pro/ENGINEER, který umožňuje vytvoření 3D animace modelů jednotlivých typů objímek včetně PE vložky a jejich umístění do acetabula. Po vydefinování výpočtových modelů na podkladě jejich mechanických vlastností systém Pro/ENGINEER vypočítal špičky napětí v místech zářezů a na obvodu objímek. Výsledky Provedené analýzy jednoznačně prokázaly nepříznivý vliv zářezů na rozložení a velikost napětí v bikonických jamkách. Varianta objímky bez zářezů má příznivější mechanické vlastnosti. Závěr Pevnostní analýzy potvrdily hlavnímu autorovi jeho správné rozhodnutí implantovat pouze nové typy objímek bez zářezů. Snižuje tím riziko mechanického selhání implantátu. Dokonalá mechanická stabilita implantátu prodlužuje životnost celé totální náhrady.
Study objective Since it was first introduced onto the market in 1993, several modifications have been made in the shape of the biconical threaded Zweymüller cup. The number of indentations on the perimeter, intended for perfect positioning of the cup, has been decreased. Due to an increased risk of possible warping or breakage of the rim at the place of indentations, the original number of 8 indentations was reduced to 4. The last innovated type is without indentations. The aim of the study is to perform a strength analysis of new cups without indentations and compare them with the control cups with indentations. Material The authors point out the advantages of biconical threaded cup, describe the material of the rim and the polyethylene liner. The decreased number of indentations on the rim perimeter has been justified. Main author presents his experience with implanting almost 400 biconical cups with 4 indentations from March 1996 to December 2007. Since January 2008, he has been only using rims without indentations. A case-report of a broken cup is also included. Methods The strength analysis was performed using Pro/ENGINEER system, enabling a creation of 3 D animated models of individual cup types, including the PE liner, and their positioning in the acetabulum. Once the calculating models were defined on the basis of mechanical characteristics, the system calculated the strain peaks in the place of indentations on the perimeters of the rims. Results The analysis clearly showed an adverse effect of indentations upon the distribution and size of strain in biconical cups. The type with no indentations showed better mechanical properties. Conclusion The strength analysis confirmed that the decision of the main author to implant only new types of rims without indentations was correct. It results in reducing the risk of mechanical failure of the implant. A perfect mechanical stability of the implant prolongs durability of the whole total hip replacement.
- MeSH
- Femoral Neck Fractures surgery therapy MeSH
- Hip Fractures surgery therapy MeSH
- Humans MeSH
- Arthroplasty, Replacement, Hip classification methods utilization MeSH
- Orthopedic Procedures methods utilization MeSH
- Tensile Strength physiology MeSH
- Postoperative Complications etiology surgery MeSH
- Joint Prosthesis classification trends utilization MeSH
- Robotics methods utilization MeSH
- Models, Theoretical MeSH
- Treatment Outcome MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Case Reports MeSH
Aseptic loosening and osteolysis are the most frequent causes of total hip or total knee arthroplasty failure. Osteolysis is induced predominantly by polyethylene particles that are produced by adhesive wear of the prosthesis. The particles trigger a complex host's reaction varying in intensity even in response to the same number of particles. These differences indicate that individual predisposition may have an important role in the pathogenesis of osteolysis. The major key mediators of wear-induced osteolysis include the cytokines RANKL, TNF-a, IL-1, IL-6 and IL-8. The inter-individual differences in the extent of bone destruction may therefore be related to variation in the amount and/or activity of these cytokines based on their gene polymorphism. Our pilot study suggests an association of some variants of the cytokine genes (e.g., IL1A-889) with a predisposition to development of severe osteolysis. If this assumption is confirmed by future investigations, this approach can facilitate the pre-operative identification of patients at risk of the development of severe periprosthetic osteolysis and premature failure of the implant.
- MeSH
- Cytokines genetics immunology MeSH
- Research Support as Topic MeSH
- Humans MeSH
- Disease Susceptibility immunology MeSH
- Osteolysis genetics immunology physiopathology MeSH
- Polymorphism, Genetic genetics immunology MeSH
- Joint Prosthesis classification MeSH
- Prosthesis Failure MeSH
- Check Tag
- Humans MeSH
V poslednej dobe stúpa výskyt osteoartrotických ochorení, ktoré svojou závažnosťou, terapeutickými úskaliami a pomerne častou invalidizáciou postihnutého predstavujú významný medicínsky, spoločenský a ekonomický problém. Na druhej strane však pokroky dosiahnuté v ortopédii, najmä v oblasti rekonštrukčných operácií, umožňujú čiastočný, resp. úplný návrat postihnutých jednotlivcov do normálneho života. Jedným z takýchto zákrokov je aj aplikácia totálnej endoprotézy bedrového kĺbu. Vlastná operácia však predstavuje za č iatok tohto procesu. Po nej nasleduje rehabilita č ná liečba, ktorá výraznou mierou prispieva k znovuobnoveniu funkcie postihnutého kĺbu. Z praxe, ako aj z citovanej literatúry vyplýva, že spôsob a kvalita rehabilitačnej liečby sú určujúcimi faktormi miery obnovenia činnosti operovaného kĺbu. Vo svojej práci sa zaoberám porovnaním výsledkov pooperačnej rehabilitačnej liečby pacientov, ktorí absolvovali trojtýždňovú predoperačne indikovanú pohybovú liečbu, so súborom pacientov, ktorí túto predoperačnú pohybovú liečbu neabsolvovali.
The number of osteo-arthrotic diseases is being increased in the last time. These diseases with their severity, therapeutic problems and relatively frequ- ent disablement of affected person represent very significant medical, social and economic problem. On the other side, achieved advances in orthope- dics, especially in the region of reconstructive ope- rations, have enabled partial or complete recur- rence of affected persons to normal life. One of these operation is application of total hip joint replace- ment. Nevertherless, proper operation is only be- ginning of whole process. After this operation a rehabilitation treatment follows, contributing sub- stantialy to functional restoration of affected joint. The way and quality of rehabilitation treatment could be regarded as determining factors of degree of operated joint functional restoration. In this paper the results of postoperative rehabilitation treatment in patients absolving pre-operative three- week movement treatment are compared with ones in patients without this pre-operative treatment.
- MeSH
- Osteoarthritis, Hip surgery rehabilitation therapy MeSH
- Arthroplasty, Replacement, Hip methods rehabilitation utilization MeSH
- Osteoarthritis surgery therapy MeSH
- Postoperative Care methods psychology rehabilitation MeSH
- Preoperative Care methods psychology rehabilitation MeSH
- Joint Prosthesis classification utilization MeSH
- Rehabilitation methods MeSH
