<p>U prvom poglavlju je ukazano na potrebu ugradnje implantata u cilju ponovnog<br />uspostavljanja normalnog funkcionisanja lokomotornog sistema čoveka. Na osnovu<br />analize broja i strukture ugrađenih endoproteza zgloba kuka za 2014. i 2015. godinu na<br />IOHB „Banjica“, Beograd, i Kliničkom centru Vojvodine Novi Sad, Klinika za ortopediju<br />i traumatologiju, zaključuje se da ovi pokazatelji ukazuju na sličnost i uporedivost, sa<br />podacima iz SAD, u odnosu na broj stanovnika.<br />Drugo poglavlje, u uvodnom delu, sadrži sistematizaciju endoproteza zgloba kuka u skladu sa standardom ISO 7216. Nakon toga, dat je prikaz dosadašnjih rezultata primene tumorskih modularnih endoproteza. Pažnja je poklonjena opisu i varijantnosti konstrukcionih elemenata modularnih endoproteza zgloba kuka, kao i analizi izvedenih konstrukcionih rešenja. Prikaz dosadašnjih istraživanja je upotpunjen analizom patentnih rešenja modularnih endoproteza zgloba kuka. Na kraju, polazeći od prethodno sumiranih saznanja, i iskustva u razvoju protetičkih pomagala je definisan cilj istraživanja, osnovne hipoteze, materijal i metode.<br />Treće poglavnje sadrži kratak prikaz koštanih tumora i istorijat tumorske<br />endoproteze. Ukazuje se na komplikacije nakon ugradnje kao i na kriterijume za ugradnju<br />tumorske endoproteze. Primarni i sekundarni tumori, neuspela aloartroplastika,<br />prelomi preko ili ispod trohantera, patološki prelom, često prouzrukuju totalno<br />razaranje gornjeg dela butne kosti, i ovi uslovi predstavljaju indikaciju za zamenu<br />gornjeg dela butne kosti tumorskom endoprotezom. Cilj ugradnje tumorske endoproteze<br />zgloba kuka je da se spase ekstremitet, očuva estetika i obezbedi zadovoljavajuća<br />funkcionalnost i neutrališe prisustvo bola. Ne može se očekivati da endoprotetski<br />sistem ima neograničen vek. Za pojedine delove koji su izloženi intenzivnom habanju u<br />toku eksplatacije potrebno je obezbediti mogućnost jednostavne zamene uz minimalan<br />hirurški zahvat.</p><p>Sa biomehaničkog aspekta projektovanja, sistem fiksacije i konfiguracija tela<br />endoproteze mora biti takav da minimizira naponsko stanje ili obezbedi povoljniju<br />raspodelu napona.<br />Četvrto poglavlje je posvećeno definisanju strukture i dimenzija komponenti sistema<br />tumorske modularne endoproteze zgloba kuka. Ukazuje se na postupak i uticajne faktore<br />na proces projektovanja, kao i na pouzdanost projektovanog rešenja. Posebna pažnja je<br />posvećena dimenzionisanju donje komponente endoproteze sa stanovišta pojave<br />koncentracije napona, kao i elementima za vezu i stezanje komponenti u jedinstven<br />mehanički sistem. Dimenzije pojedinih komponenti su definisane na bazi statističkih<br />razultata do sada ugrađenih tumorskih monolitnih endoproteza na IOHB „Banjica“<br />Beograd.<br />U okviru petog poglavlja, prikazani su rezultati računarske analize statičkog<br />ponašanja tela monolitne, odnosno donje komponente tumorske modularne endoproteze<br />zgloba kuka. Prvo su prikazana preliminarna ipsitivanja pri statičkom opterećenju, i to<br />računarsko simuliranje eksperimentalnih ispitivanja i sama eksperimentalna<br />ispitivanja za obe vrste tumorskih endoproteza. Na bazi ovih rezultata izvršeno je<br />remodelovanje donje komponente i umesto radijusa prelaza između kragne i tela - mesto<br />maksimalnih napona u implantatu, definisan je optimalni bionički profil prelaza.<br />Nakon izrade donjih komponenti od različitih materijala i različitih profila prelaza<br />realizovana su završna ispitivanja komponenti tumorske modularne endoproteze pri<br />statičkom opterećenju. I kod završnog ispitivanja prvo je izvršeno računarsko<br />modelovanje a nakon toga i eksperimentalno ispitivanje. Pri eksperimentalnom<br />ispitivanju meren je napon u jedanaest mernih tačaka po profilu prelaza između kragne<br />i tela. Dobijeni rezultati su poređeni sa računarskim modeliranjem i konstatovano je<br />zadovoljavajuće poklapanje raspodele i maksimalnih napona po profilu prelaza između<br />kragne i tela endoproteze. Za slučaj delovanja dinamičkog opterećenja izvršena su<br />eksperimentalna laboratorijska ispitivanja. Pri ovom ispitivanju definisane su<br />sledeće promenljive: 1. vrsta endoproteze: monolitna i modularna, 2. materijal:<br />superlegure čelika 316LVM i titanijuma Ti6Al4V, 3. oblik prelaza: sa radijusom i<br />optimizirani prelaz. Cilj ovog ispitivanja ja da se utvrdi broj ciklusa koji će dovesti<br />do početka razlabavljenja tela endoproteze pri maksimalnim uslovima opterećenja, tj.<br />da li navedene promenljive daju statistički značajnu razliku u broju ciklusa do pojave<br />razlabavljenja, kasne mehaničke komplikacije koja prethodi lomu usled zamora<br />materijala, ili zahteva reviziju. Pri ovom ispitivanju fizički prototipovi<br />endoproteza su, izloženi jednosmerno promenljivoj sili, Fmax=2500N, amplitude 2000N i<br />frekvencije 15-20 Hz. Vršena je vizuelena kontrola pojave radiolucentne linije između<br />tela endoproteze i koštanog cementa, odnosno kosti, kao pouzdani znak početka<br />razlabavljenja, kao i Rtg snimaka od strane ortopedskih hirurga nakon svakih 500.000<br />ciklusa, za sve uzorke. Analiza rezultata nakon ispitivanja pri dinamičkom opterećenju<br />uzoraka izrađenih od superlegure čelika 316LVM i uzoraka izrađenih od superlegure<br />titanijuma Ti6Al4V ukazuje na visoku pouzdanost odnosno nizak nivo rizika da može doći<br />do razlabavljenja i do pojave loma usled zamora materijala. Profil prelaza sa velikog<br />na mali prečnik za slučaj radijusa i optimizirani bionički profil nisu pokazali<br />značajnu statističku razliku kod ispitivanja pri dinamičkom opterećenju. Na kraju je<br />pojava razlabavlja utvrđivana i inženjerskom metodom. Nakon ispitivanja dinamičkim<br />opterećenjem fizički prototipovi endoproteza su ponovo izloženi statičkom<br />opterećenju i konstatovano je da nema značajnijih promena u raspodeli i vrednostima<br />maksimalnih napona, što ukazuje da nije došlo da pojave razlabavljenja.<br />Kroz šesto poglavlje dat je kratak opis biokompatabilnih materijala, legura čelika<br />316LVM, kobalta CoCrMo, titanijuma Ti6A14V „eli“, poroznih i keramičkih materijala,<br />materijala od plastične mase, kompozita i bioreseptivih materijala. Nakon toga su<br />prikazani rezultati ispitivanja biokompatabilnosti materijala koji su primenjeni za<br />izradu elemenata modularnog sistema endoproteza. Rezultati ispitivanja su pokazali<br />da materijali i tehnološki proces proizvodnje zadovoljavaju sa stanovišta<br />biokompatabilnosti.<br />Sedmo poglavlje sadrži zaključke, na osnovu rezultata pojedinih poglavlja i<br />izvedenih istraživanja. Nakon toga dati su pravci budućih istraživanja.<br />Osmo poglavlje sadrži pregled korišćene literature, koju čini 68 literaturnih<br />naslova od kojih je najveći broj citiran u radu.</p> / <p>In the first chapter, the need of implant insertion was apostrophed, with the purpose to achieve<br />normal functioning of human locomotory system. On the base of analysis of the number and the<br />structure of implanted hip endoprosthesis during the years 2014. and 2015. at IOHB “Banjica”,<br />Belgrade, and at Clinical center of Vojvodina, Novi Sad, Clinic of orthopedy and traumatology, it<br />was concluded that the data, related to the number of citizens, show to be similar and<br />comparable with those from the USA.<br />In the second chapter, in the preface section, the systematization of hip endoprosthesis<br />according to the norm ISO 7216 was presented. After that, the results of historical application of<br />modular tumor endoprosthesis was presented. The attention was paid to the description and<br />structure element variants of modular hip endoprosthesis, and also to the analyses of existing<br />prosthesis constructions. The results of up to now conducted research were additionally enriched<br />with patented variants of modular hip endoprosthesis. At the end, based on previously summed<br />knowledge and experiences in the field of development of prosthetic aids, the goal of the<br />research was determined, so as basic hypothesis, materials and methods.<br />Third chapter comprises short description of bone tumors and historic development of tumor<br />endoprosthesis. The complications after implantation were discussed and also the criteria for the<br />implantation of tumor prosthesis. Primary and secondary tumors, failed arthroplasty, fractures<br />across or beneath trochanter and pathologic fractures are frequent causes of total destruction of<br />the upper portion of the femur and require the replacement of it with tumor prosthesis. The aim of<br />hip tumor prosthesis implantation is to save the limb, to preserve esthetic, to provide satisfactory<br />functionality and to neutralize the pain. It is not possible to expect that endoprosthetic system<br />achieves en infinitely long service life. For some of the components, which are during the service<br />exposed to intensive wear and tear, it is necessary to provide the possibility of simple<br />replacement, with the need for a minimal surgical intervention. From the aspect of biomechanical</p><p>design, the fixation system and body configuration of an endoprosthesis must be such, as to<br />minimize stress level and to provide for a convenient stress distribution.<br />The fourth chapter is dedicated to the definition of the structure and components’ dimensions<br />for a system of modular hip endoprosthesis. It was dealt with the procedure and with the<br />influencefull factors on a design process and also with the reliability of a designed solution.<br />Special care was devoted to the dimensioning of the upper portion of endoprosthesis from the<br />standpoint of stress concentration and to the elements for the connection and joining the<br />elements in a compact mechanical system. The measures of certain components were defined<br />on the base of statistic analysis of up to now implanted monolithic tumor endoprosthesis at IOHB<br />“Banjica”, Belgrade.<br />Within fifth chapter, the results of computer analysis of static behavior of the body of monolithic<br />component (lower section) of modular tumor hip endoprosthesis was presented. As the first, the<br />results of preliminary examinations with static load were presented, both the computer simulation<br />of experimental testing and the results of real experimental testing, for both types of tumor<br />endoprosthesis. On the base of these results, the remodeling of the lower component was<br />undertaken so that instead of the connection of a collar and the prosthesis body with the shape<br />of a constant radius (the spot with the maximum stress in the prosthesis), an optimal bionically<br />shaped connection was defined. After the production of lower prosthesis components from<br />different materials and with the different shapes, the final examinations of the components of<br />modular tumor hip endoprosthesis under static load were performed. For the final examinations,<br />in the first step also the computer modeling was performed, and consequently experimental<br />testing. When performing experimental testing, the stress level was determined at eleven<br />measuring spots, on the prosthesis section between the collar and the body. Acquired results<br />were compared to the results acquired through computer modeling and an adequate overlapping<br />of stress distribution and maximum stress in the region between the collar and the prosthesis<br />body was detected. For the case of dynamic load, the laboratory experimental examinations<br />were performed. For these examinations the following variables were determined: 1.<br />endoprosthesis type: monolithic and modular, 2. material: steel superalloy 316LVM and of<br />titanium Ti6Al4V, 3. shape of a connection between the collar and prosthesis body: with constant<br />radius and with the optimized shape. The aim of this examination was to determine the number<br />of cycles which would lead to the beginning of the loosening of the prosthesis body under the<br />conditions of maximum load or, with other words, it was to be determined if mentioned variables<br />provide for significant statistic difference in cycle numbers to the point of prosthesis loosening, to<br />the consequent mechanic complication predicting material fatigue failure or demanding surgical<br />revision. When conducting the examination, physical models of endoprosthesis were exposed to<br />the influence of unidirectionally changing force with the parameters of Fmax = 2500N, Fampl =<br />2000N, frequency 15-20 Hz. After every 500.000 load cycles, for all the samples, the appearance<br />of a radiolucent line between the prosthesis body and bone cement and the bone itself, as the<br />reliable sign of the loosening onset, was visually checked on Rtg shots by orthopedic surgeons.<br />The analysis of the results for behavior under dynamic load, for the samples from steel<br />superalloy 316LVM and from titanium Ti6Al4V shows that they posses high reliability and that<br />there is a low probability that the loosening and the fatigue failure will occur. When examined<br />under dynamic load, prosthesis section with the change from small diameter to large diameter,<br />for the case with constant radius and for the case with optimized bionic profile, have not shown<br />statistically significant difference. At the end, the loosening appearance was examined under the<br />application of engineering methods. After exposing the prosthesis to the dynamic load, physical<br />prototypes of prosthesis were anew exposed to static load and it was confirmed that there is no<br />significant change in the distribution and the level of maximum stress, what was the proof that no<br />loosening has occurred.<br />Within the sixth chapter, the short description of biocompatible materials was given, of steel<br />alloy 316LVM, cobalt CoCrMo, titanium Ti6Al4V “eli”, of porous and ceramic materials, plastic<br />materials, composites and bioreceptive materials. Subsequently, the results of biocompatibility<br />examination of materials which were applied for the production of the elements of modular<br />endoprosthesis system were presented. The acquired results have proved that the materials and<br />the production process are satisfactory from the standpoint of biocompatibility.<br />Seventh chapter comprises the conclusions, based on specific previous chapters and the<br />research results. After that, the suggestions for the future research were outlined.<br />Eight chapter comprises an overview of used literature, with 68 titles, most of which were cited<br />in this work.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)105333 |
| Date | 24 February 2018 |
| Creators | Grujić Jovan |
| Contributors | Zeljković Milan, Tabaković Slobodan, Milankov Miroslav, Baloš Sebastian, Baščarević Zoran, Živković Aleksandar |
| Publisher | Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, University of Novi Sad, Faculty of Technical Sciences at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | Unknown |
| Type | PhD thesis |
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