Дисертації з теми "Femoral implants"
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Tirunagari, Prashanthi. "Nanomechanical characterization of femoral head materials." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/5906.
Повний текст джерелаThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 30, 1981) Includes bibliographical references.
Cook, Juliette Emma. "Fretting wear of total hip replacement femoral stems." Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263286.
Повний текст джерелаSchmitz, Mark James. "Exploration of mechanical factors in the failure of femoral hip implants." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425795.
Повний текст джерелаCarli, Alberto. "FGF 18 augments bone healing & osseointegration of intra-medullary femoral implants in osteopenic bone." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110402.
Повний текст джерелаIntroduction: La fixation interne de fractures dans la présence de l'ostéopénie a été associée à un taux d'échec aussi élevé que 25%. Amélioration de la formation osseuse et l'ostéo-intégration de matériel orthopédique est une priorité pour le traitement de patients. Facteur de croissance des fibroblastes (FGF) 18 régit le développement squelettique et pourrait donc avoir des applications dans intégration de l'implant. Cette étude a été conçue pour déterminer si le FGF 18 favorise la formation osseuse et l'ostéo-intégration dans le ostéopénique FGFR3-/- souris et d'examiner son effet sur la moelle osseuse provenant de cellules souches mésenchymateuses (CSM).Méthodes: Implants intramédullaires ont été fabriqués à partir de tiges de nylon 10mm x 0,4 revêtus de 300nm de titane par dépôt de vapeur physique. Les souris de type FGFR3-/- et souris de type sauvage a reçu des implants intramédullaires au femurs. Les fémurs gauche ont reçu une injection intra-médullaire de 0.1μg de FGF 18 (Merck Serono), et les fémurs droit ont reçu une solution saline seule. Après six semaines, les fémurs ont été récoltés, analysé par les micro CT, et préparé pour l'histologie. Les CSM ont été récoltées à partir de fémurs et les tibias de souris de type FGFR3-/ - et de type sauvage. Les cellules ont été cultivées dans 'Alpha Modified Eagle's Medium' (aMEM) pour surveiller la proliferation, ou cultivées dans un milieu 'aMEM' complété avec de l'acide ascorbique et de sodium bêta-glycérophosphate pour surveiller la différenciation. La prolifération a été évaluée par dénombrement des cellules et l'activité métabolique aux jours 3, 6 et 9. Différenciation a été évaluée par coloration pour les ostéoblastes et les dépôts minéraux aux jours 6, 9 et 12.Résultats: Les souris de type sauvage ont produit plus d'os péri-implantaire par rapport à FGFR3-/ - souris. La formation osseuse péri-implantaire à la jonction proximale métaphysodiaphysaire a été augmenté en fémurs traités avec FGF18 par rapport aux fémurs de contrôle controlatéraux dans de type sauvage (p > 0.05) et FGFR3-/ - (p = 0.04). L'analyse histologique a corroboré les conclusions micro CT. Les femurs FGFR3-/ - qui ont recus FGF 18 traités fémurs ont formé l'os autour de l'implant au lieu de la réponse fibreuse vu dans les contrôles. Des études in vitro ont montré que la proliferation du MSC ont été augmenté avec FGF18 d'une manière dose-dépendante pour les type sauvage et les type FGFR3-/ -. La différenciation des ostéoblastes a été inhibée par FGF18 pour les CSM du type sauvage. Aucun effet significatif sur la différenciation a été observé dans les cellules récoltées à partir de souris FGFR3-/ -.Conclusion: FGF 18 augmente la formation osseuse et l'ostéo-intégration des implants intramédullaires chez la souris ostéopéniques. FGF 18 augmente la prolifération des CSM à la présence et l'absence de FGFR3. FGF18 inhibe également la différenciation ostéoblastique a la présence de FGFR3. Les effets de FGF 18 sur le prolifération des CSM et l'ostéogenèse est probablement dû à la signalisation grâce à un FGFR alternative, probablement FGFR1 ou 2. Des travaux in vivo supplémentaires sont nécessaires pour confirmer l'identité de l'autre FGFR et d'évaluer sa capacité à améliorer la cicatrisation de l'os en environnements défavorable
Feldt, Christian E. "Stress shielding minimized in femoral hip implants a finite element model optimized by virtual compatibility." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4892.
Повний текст джерелаID: 030423147; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 86-91).
Ph.D.
Doctorate
Mechanical, Materials, and Aerospace Engineering
Engineering and Computer Science
Arsiwala, Ali, and Vatsal Shukla. "FE Modelling Of Two Femur Fixation Implants." Thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-180127.
Повний текст джерелаWang, Allan W. "Femoral bone remodelling following cemented hip arthroplasty in a sheep model /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phw2462.pdf.
Повний текст джерелаKhaw, Fu-Meng. "Osseointegration of hydroxyapatite coated femoral prostheses : a clinicopathological and biomechanical study of human autopsy retrieved implants." Thesis, University of Newcastle upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289162.
Повний текст джерелаBrumby, Scott Andrew. "The effect of surface roughness and a collar on fixation of cemented femoral stems in vivo /." Title page, table of contents and summary only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phb8934.pdf.
Повний текст джерелаShultz, Travis R. "The effects of cortical bone viscoelasticity on the fixation/stability of cemented and cementless femoral implants a finite element analysis /." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2550.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains vii, 79 p. : ill. Includes abstract. Includes bibliographical references (p. 71-79).
Kazemian, Marvi Salman. "Biomechanical rationale of episiotomy for removal of femoral components: In vitro investigation for removal of well-fixed implants. An artificial implantation model for the simulation of implant-bone interface." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/115801/1/Salman_Kazemian%20Marvi_Thesis.pdf.
Повний текст джерелаParker, Trevor Wayne. "Functional outcome and complications after treatment of moderate to severe slipped upper femoral Epiphysis with a modified Dunn procedure." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5447.
Повний текст джерелаHazlehurst, Kevin Brian. "The adoption of laser melting technology for the manufacture of functionally graded cobalt chrome alloy femoral stems." Thesis, University of Wolverhampton, 2014. http://hdl.handle.net/2436/332114.
Повний текст джерелаVan, den Heever David Jacobus. "Development of patient-specific knee joint prostheses for unicompartmental knee replacement (UKR)." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17942.
Повний текст джерелаENGLISH ABSTRACT: The knee is the largest, most complicated and incongruent joint in the human body. It sustains very high forces and is susceptible to injury and disease. Osteoarthritis is a common disease prevalent among the elderly and causes softening or degradation of the cartilage and subcondral bone in the joint, which leads to a loss of function and pain. This problem can be alleviated through a surgical intervention commonly termed a “knee replacement”. The aim of a knee replacement procedure is to relieve pain and restore normal function. Ideally, the knee replacement prosthesis should have an articulating geometry similar to that of the patient’s healthy knee, and must allow for normal motion. Unfortunately, this is often problematic since knee prostheses are supplied in standard sizes from a variety of manufacturers and each one has a slightly different design. Furthermore, commercial prostheses are not always able to restore the complex geometry of an individual patient’s original articulating surfaces. This dissertation shows that there is a significant variation between knee geometries, regardless of gender and race. This research aims to resolve the problem in two parts: Firstly by presenting a method for preoperatively selecting the optimal knee prosthesis type and size for a specific patient, and secondly by presenting a design procedure for designing and manufacturing patient-specific unicompartmental knee replacements. The design procedure uses mathematical modelling and an artificial neural network to estimate the original and healthy articulating surfaces of a patient’s knee. The models are combined with medical images from the patient to create a knee prosthesis that is patient-specific. These patient-specific implants are then compared to conventional implants with respect to contact stresses and kinematics. The dissertation concludes that patient-specific implants can have characteristics that are comparable to or better than conventional prostheses. The unique design methodology presented in this dissertation introduces a significant advancement in knee replacement technology, with the potential to dramatically improve clinical outcomes of knee replacement surgery.
AFRIKAANSE OPSOMMING: Die knie is die grootste, mees komplekse en mees ongelyksoortige gewrig in die liggaam. Osteoarthritis is ’n siekte wat algemeen by bejaardes voorkom en die versagting of agteruitgang van die kraakbeen en subchondrale bene in die gewrig tot gevolg het, wat tot ’n verlies van funksionering en pyn lei. Hierdie probleem kan verlig word deur ’n chirurgiese ingryping wat algemeen as ’n “knievervanging” bekend staan. Die doel van ’n knievervangingsprosedure is om pyn te verlig en normale funksionering te herstel. Ideaal gesproke behoort die knievervangingsprostese ’n gewrigsgeometrie te hê wat soortgelyk aan die pasiënt se gesonde knie is, en normale beweging moontlik maak. Ongelukkig is dit dikwels problematies aangesien knieprosteses in standaardgroottes en deur ’n verskeidenheid vervaardigers verskaf word, wat elkeen se ontwerp effens anders maak. Verder kan kommersiële prosteses nie altyd die komplekse geometrie van ’n individuele pasiënt se oorspronklike gewrigsoppervlakke vervang nie. Hierdie proefskrif wys dat daar ’n betekenisvolle variasie tussen knieafmetings is, afgesien van geslag en ras. Hierdie navorsing is daarop gemik om die problem op tweërlei wyse te benader: Eerstens deur ’n metode aan te bied om die optimal knieprostesetipe en -grootte vir ’n spesifieke pasiënt voor die operasie uit te soek, en tweedens om ’n ontwerpprosedure aan te bied vir die ontwerp en vervaardiging van pasiëntspesifieke unikompartementele knievervangings. Die ontwerpprosedure gebruik wiskundige modellering en ’n kunsmatige neurale netwerk om die oorspronklike en gesonde gewrigsoppervlakke van ’n pasiënt se knie te bepaal. Die modelle word met mediese beelde van die pasiënt gekombineer om ’n knieprostese te skep wat pasiëntspesifiek is. Hierdie pasiëntspesifieke inplantings word dan met konvensionele inplantings vergelyk wat kontakstres en kinematika betref. Daar word tot die slotsom gekom dat die pasiëntspesifieke inplantings oor eienskappe kan beskik wat vergelykbaar is met of selfs beter is as dié van konvensionele prosteses. Die unieke ontwerpmetodologie wat in hierdie proefskrif aangebied word, stel beduidende vordering in knievervangingstegnologie bekend, met die potensiaal om die kliniese uitkomste van knievervangingsoperasies dramaties te verbeter.
Shao, Fei. "Natural frequency analysis for osseointegration trans-femoral implant." Thesis, University of Surrey, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443397.
Повний текст джерелаVieira, Eugénio Vítor Caldeira. "Desenvolvimento de um novo conceito de implante patelo-femoral." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/9943.
Повний текст джерелаO joelho é uma das articulações mais importantes do corpo humano, permite a mobilidade e a estabilidade em simultâneo. Algumas patologias como a síndrome patelo-femoral podem conduzir à necessidade da realização da artroplastia patelo-femoral. Vários efeitos comprometem a longevidade desta artroplastia, sendo os mais frequentes o efeito de stress shielding, responsável pela reabsorção óssea localizada, o efeito de fadiga por sobrecarga associado à geração de microfissuras e colapso do osso de suporte, e a osteólise provocada pela fratura e libertação de micropartículas do cimento-ósseo. Os parâmetros biomecânicos associados a estes efeitos foram estudados em três implantes comerciais; Journey PFJ (Smith & Nephew Inc), Vanguard PFR (Biomet Inc) e Zimmer PFJ (Zimmer Inc). Adicionalmente foram ainda propostos seis novos modelos de implante por forma a tentar melhorar o desempenho destes, tendo sido este o principal objetivo deste trabalho. Para a análise dos parâmetros biomecânicos (deformações no osso e tensões no cimento ósseo) foram utilizados modelos de elementos finitos desenvolvidos a partir de imagens médicas de TAC de um paciente saudável. Foram simuladas as condições de carga para três atividades fisiológicas distintas; ciclo de marcha, subir escadas e agachamento profundo. Estas análises foram realizadas por forma a serem representativas de duas situações clínicas distintas, uma representativa do curto termo, em que o cimento-ósseo foi considerado rigidamente ligado ao osso e outra representativa do longo termo, em que o cimento-ósseo foi considerado apenas em contacto com atrito com o osso, ou seja uma situação de descolamento desta interface. Após a análise comparativa dos diferentes modelos implantados relativamente aos modelos intactos, verificou-se que nas regiões de bordo dos implantes comerciais os níveis de deformação no osso esponjoso são bastante elevados tendo todos os modelos apresentando um risco de falência por fadiga, devido a sobrecarga localizada, sendo o risco mais elevado associado à atividade de agachamento. O efeito stress shielding foi observado com diferentes graus, em todos os modelos na zona central do implante. O cimento ósseo apresentou várias zonas com tensões de von Mises superiores à tensão limite de fadiga para os casos da atividade de subir escadas e agachamento. Os novos modelos de implante patelo femoral propostos apresentam comportamentos comparáveis aos observados nos implantes comerciais, no entanto uma das novas propostas de implante sugere um melhor compromisso de entre todos os implantes analisados.
The knee joint is one of the most important articulations of the human body, allowing simultaneous mobility and stability. Some pathologies such as patellofemoral syndrome can lead to patellofemoral arthroplasty. The longevity of arthroplasty is compromised by various effects, being the most frequent the effect of stress shielding, responsible for the located bone reabsorption, the effect of fatigue by overcharge associated to the generation of microfissures and the collapse of the supporting bone, and the osteolysis provoked by the fracture and release of microparticle of bone cement. The biomechanical parameters associated with these effects were studied in three commercialized implants; Journey PFJ (Smith & Nephew Inc.), Vanguard PFR (Biomet Inc.) and Zimmer PFJ (Zimmer Inc). Additionally there were also proposed six new models of implants in order to try to improve their performance, being this the main goal of this work. To analyze the biomechanical parameters (bone strain and bone cement stress) there were used the finite element models developed from CT medical images of a healthy patient. Three different loading conditions for three distinct physiological activities were simulated: gait cycle, climb stairs and deep squat. These analyzes were performed to represent two distinct clinical situations, a representative of the short term, were the bone cement was considered rigidly connected to the bone and another representative of the long term, were the bone cement was found only in frictional contact with the bone, in other words, a state of detachment of this interface. After comparative analysis of the different models implanted with the intact models, it was found that in the edge regions of the commercialized implants the levels of deformation in the cancellous bone are quite high with all models presenting a risk of fatigue failure due to localized overload, and the higher risk is associated with the squatting. The stress shielding effect was observed with varying degrees, in all models in the central area of the implant. The bone cement showed several areas with von Mises stresses above the fatigue limit stress for cases climbing stairs and squatting. The new models of patellofemoral implant proposed exhibit behaviors similar to those seen in commercial implants, however one of the new proposed implants suggests a best compromise amongst all implants analyzed.
Whatley, Stephen Charles. "Computational Simulation of a Femoral Nail Fracture." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1558645340226381.
Повний текст джерелаMcMillan, Iain A. "Development of an intervertebral disc implant, biomodelling methodology and a femoral endoprosthesis." Thesis, University of Canterbury. Mechanical Engineering, 2004. http://hdl.handle.net/10092/6537.
Повний текст джерелаRoe, John Andrew. "How important is length? : mechanical testing and measurement of a cemented, polished, tapered femoral implant." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/53200/1/John_Roe_Thesis.pdf.
Повний текст джерелаFilho, Geraldo Dantas Silvestre. "Projeto e análise estrutural de haste femoral de implante de quadril em material compósito polimérico." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-17012011-112250/.
Повний текст джерелаA design and structural analysis of a femoral stem using a polymeric composite material is proposed in this work. The work had some steps in order to achieve trusty parameters for the material behavior aiming the consistence of numerical and experimental results. In the first step, a bibliographic review of mechanical behavior of reinforced polymeric composite materials as well as failure criterion was done. Following experimental steps are presented with specimen manufacturing procedure description and the results obtained from quasi-statics tension tests of polyurethane derivated from castor oil. The next step was the development of a monotonic quasistatic test device for the polyurethane femoral stem aiming to determine the forcedisplacement curve according to ISO 7206-3 and ISO 7206-4 standards. Considering the experimental results obtained it was possible to propose a structural reinforcement, which consists on a tube, in the polyurethane femoral stem and to adopt a progressive failure analysis in order to determine its mechanical behavior. A material model using FORTRAN sub-routine was developed and compiled joint with a finite element program (ABAQUS). The conclusion is that the model developed and the structural proposed reinforcement for the femoral stem bring innovation for this contribution once it is possible to preview accurately the mechanical behavior of the reinforced femoral stem with tube in polymeric composite material.
Taylor, Stephen James Guy. "Wireless telemetry of forces from femoral replacements in man : system design and implant fixation study." Thesis, University College London (University of London), 1998. http://discovery.ucl.ac.uk/1451582/.
Повний текст джерелаBhatt, Himanshu K. "FINITE ELEMENT OPTIMIZATION OF HIP IMPLANT GEOMETRICAL PARAMETERS TO DETERMINE SAFE ZONES AND RESIST DISLOCATION." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1229659570.
Повний текст джерелаGuirao, Cano Lluis. "Valoración de un implante endomedular en la funcionalidad de los pacientes amputados femorales." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/283586.
Повний текст джерелаIntroduction Lower-limb amputation is a permanent surgical procedure that leads to a series of physical, psychological and social consequences that may affect the quality of life of the amputee.The percentage of transfemoral amputations in Europe is estimated in 20-35% of all lower limb amputations. Around 75% of the individuals who require an amputation of the lower limb are over 65 years old. Several studies have shown that individuals with a knee disarticulation have less oxygen consumption during gait performing and have less residual limb osteoporosis than individuals with a transfemoral lower limb amputation. Objective of the study The objective of this study was to investigate the functional level of individuals with a transfemoral amputation and an implant that allows distal support to the residual limb, as well as to investigate the clinical improvement in terms of pain, quality of life, residual limb control and stability, improvement of the bone mineral density and decrease of the energy expenditure when comparing with the use of a conventional socket in individuals with an above knee amputation. Materials and methods This is an experimental prospective non randomized study before-and-after intervention type developed at the Hospital de Mataró in 10 individuals with transfemoral amputation after a titanium implant placement between March 1st,2011 and March 1st, 2013. The local Ethics Committee of Hospital de Mataró approved the study and patients gave informed consent before being enrolled as participants. Results The average age was 50,3 ±16,3 years, with a higher proportion of men participating 6 (60%). The average of time since lower limb amputation was 96,9 ± 96,3 months, most of them, amputation of the right lower limb 6 (60%). The most prevalent aetiology of amputation was traumatic in 6 participants (60%). All participants had been amputated in the middle third of the femur. At the end of the 14 months of follow-up, participants significantly improved the total of meters walked in the 2 MWT, the mean was 122,5 meters (p=0,008) and they also improved the speed of gait, from 49,2 m/s before intervention to 61,3 m/s 14 months after (p=0,008). An improvement in pain was observed too after surgery (2,9 vs 0,4 p=0,04) and the number of hours using the prosthesis also improved after intervention (10,1h vs 12,9 h p=0,01). Conclusions The results of our study show an improvement in the functional capability in terms of number of meters walked and speed of gait using the 2MWT, in individuals with a lower limb amputation mainly secondary to peripheral vascular disease, 14 months after surgery for a femoral implant placement.
Harvey, Edward J. "The effective limit of implant flexibility in optimizing femoral bone remodeling and stem fixation after non-cemented total hip arthroplasty /." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29441.
Повний текст джерелаDespite the marked increase in stem flexibility with the composite stem, there was no statistically significant difference in the overall degree of femoral stress shielding, cortical area, or cortical porosity when compared with the stiffer titanium stem at either time period. Overall, the tissue response to the more flexible composite stem resulted in less bone ingrowth and more radiopaque line formation at the bone-implant interface than with the titanium stem. (Abstract shortened by UMI.)
Trubačová, Pavlína. "Pokročilá výroba individuálních ortopedických implantátů technologií selektivního tavení laserem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-256549.
Повний текст джерелаFaria, Luís Guilherme de. "Estudo biomecânico de dois modelos de implante não cimentado para a artroplastia total do quadril em modelo canino." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/152784.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste estudo foi comparar as propriedades biomecânicas de dois modelos de hastes femorais da prótese total de quadril, não cimentada, modular e nacional. A haste A, possui uma extensão na base do colo do implante, denominado “colar”, já o implante B, possui a sua porção proximal abaulada. Buscou-se determinar qual dos dois modelos de hastes femorais tem melhor desempenho ao evitar, ou impedir, o afundamento (subsidence). Para tal, utilizou-se 8 pares de fêmures de cães adultos, machos e fêmeas, de diferentes raças e massa corporal de ±25 kg. Em cada fêmur, uma ostectomia da cabeça e do colo femoral foi realizada e inserido um dos implantes selecionados. As construções foram submetidas, previamente, à radiografia e densitometria óssea, a fim de determinar a homogeneidade da amostra. Logo em seguida, divididos em dois grupos, Haste A (8 fêmures) e Haste B (8 fêmures), aplicou-se carga de flexo-compressão, no eixo axial de cada amostra, em máquina universal de ensaios. A força máxima, a deflexão, a resistência à compressão e a energia foram as variáveis analisadas nos dois sistemas, assim, o Grupo B exibiu valores significativamente maiores (p≤0,05) para as variáveis resultantes deste estudo, com exceção da rigidez que, estatisticamente, considerou-se similar entre os dois grupos (p=0,2031). A média da força máxima no teste de compressão axial para o Grupo A foi de 1347±357 N e, para o Grupo B, de 1805±123 N (p≤0,0069). A média da deflexão para o Grupo A foi de 5547±2639 mm e, para o Grupo B, de 10033±3998 mm (p≤0,0056). Para a variável energia, a média da força máxima para o Grupo A foi de 6203±3488 N.mm, já para o Grupo B, foi de 12885±5056 N.mm (p≤0,0054). A média do módulo de deformação elástica, expresso em rigidez, no Grupo A foi de 860±160 N/mm, já no Grupo B, de 1011±305 N/mm (p≤0,0054). Os dados obtidos apresentavam distribuição normal e foram submetidos ao teste t pareado (p≤0,05). Constatou-se que a Haste B possui maior força máxima, deflexão e energia. Todavia, quanto a rigidez, ambas são eficientes em amortizar o impacto das forças axiais de flexo-compressão em fêmures cadavéricos de cães.
The goal of this study was to compare the biomechanical properties of two models of femoral stems of the total hip, uncemented, modular, and national (Brazil) prosthesis. The stem A has an extension at the base of the implant, called the "collar", and the implant B, has its convex proximal portion. We sought to determine which of the two models of femoral rods perform best by avoiding, or preventing, subsidence. To this end, we used eight pairs of femurs of adult dogs, male and female, of different races and body weight ± 25 kg. In each femur, an ostectomy of the head and femoral neck was performed and inserted one of the selected implants. The constructs were previously submitted to radiography and bone densitometry, in order to determine the homogeneity of the sample. Then, divided into two groups, Stem A (8 femurs) and Stem B (8 femurs), a flexo-compression load was applied on the axial axis of each sample in a universal testing machine. Maximum strength, deflection, compressive strength and energy were the variables analyzed in both systems, thus, Group B showed significantly higher values (p≤0.05) for the variables resulting from this study, except for the rigidity that, statistically, it was considered similar between the two groups (p=0.2031). The mean maximal force in the axial compression test for Group A was 1347±357 N and, for Group B, 1805 ± 123 N (p≤0.0069). The mean deflection for Group A was 5547 ± 2639 mm and, for Group B, 10033±3998 mm (p≤0.0056). For the energy variable, the mean of the maximum force for Group A was 6203±3488 N.mm, for Group B, it was 12885±5056 N.mm (p≤0.0054). The mean elastic strain modulus, expressed as rigidity, in Group A was 860±160 N/mm, in Group B, of 1011±305 N/mm (p≤0.0054). The obtained data presented normal distribution and were submitted to paired t test (p≤0.05). It was verified that Haste B has greater maximum strength, deflection and energy. However, for stiffness, both are efficient in amortizing the impact of axial flexion-compression forces on cadaverous femurs of dogs.
Salbego, Fabiano Zanini. "Enxerto ou implante homólogo na correção de defeito ósseo segmentar femoral em cães associado a inoculação da fração de células mononucleares da medula óssea." Universidade Federal de Santa Maria, 2010. http://repositorio.ufsm.br/handle/1/4041.
Повний текст джерелаBone defects due to trauma, postoperative and mutilating surgery complications, associated to removal of neoplasia, are part of the routine of hospitals and veterinary clinics. Bone grafts, within all their variants, represent the main viable alternative in the structural correction of great bone losses. Currently, the search for alternatives to correct these problems and the great potential of cellular therapy, have led numerous researchers to ingress into this line of study. The present work aimed to evaluate the influence of the hydration of bone implants conserved in glycerin 98% over their biomechanical resistance; the viability of a bone marrow harvesting protocol, for application in the clinical surgical routine; and the effect of intralesional application of bone marrow mononuclear cell fraction, over the consolidation of graft-host interface of dogs submitted to segmental bone grafting, with bone implants conserved in glycerin 98%. This research was developed in two phases. The first, ex-vivo, in which 108 bone fragments conserved in glycerin 98% were separated in six different groups, according to hydration period, and later were submitted to axial load test for biomechanical resistance evaluation. The second phase, in-vivo, in which 20 mongrel dogs, with mean weight of 13kg, were divided in four different groups according to the type of graft employed and with or without application of bone marrow mononuclear cell fraction. All animals were submitted to a bone marrow harvesting protocol, obtaining a final volume of 5ml kg-1 of body weight. The collected bone marrow was analyzed by means of myelogram and later submitted to isolation of the mononuclear cell fraction by a technique already affirmed in the literature. A diaphyseal femoral bone defect was created and repaired with the same removed segment (groups I and III) or with a bone segment conserved in glycerin 98% (groups II and IV). The bone marrow mononuclear cell fraction, after isolation, was injected via intralesional route in dogs of the treated groups (I and II), whereas the control group (III and IV) received an injection of the same volume, however, of 0.9% sodium chloride solution. The bone consolidation progress of the graft-host interfaces was followed by serial radiographic exams up to 90 days after surgical intervention, whereas the presence of mononuclear cells was followed up to seven days after implantation, by detection of Qtracker-665 nanocrystal fluorescence, used as cell marker. According to the results obtained, it can be concluded that: hydration of bone implant conserved in glycerin 98% does not produce statistically significant alterations in the biomechanical resistance of cortical bone for the different evaluated times. However, the bone mineral density has a close relationship with this property; bone marrow harvesting protocol with reduced volume of 5ml kg-1 of body weight, obtained from different long bones, proved to be adequate for isolation of mononuclear cell fraction and for obtaining a cell button with adequate number of cells and high viability, essential for the success of its therapeutic application; the consolidation of proximal and distal graft-host interfaces at 90 days after surgery no showed clinical and radiographic difference in the groups control and treated with bone marrow mononuclear cell fraction. Nevertheless, it cannot be confirmed that the cellular therapy used in this study is not an effective bone healing adjuvant, as it is believed that the restriction of load deposition on the focus of the fracture, achieved by reduced postoperative exercise, has influenced directly on the result of the consolidation.
As falhas ósseas decorrentes de trauma, complicações pós-operatórias e cirurgias mutilantes, associadas à remoção de neoplasias, fazem parte da rotina dos hospitais e clínicas veterinárias. Os enxertos ósseos, dentre todas as suas variantes, representam a principal alternativa viável na correção estrutural de grandes perdas ósseas. Na atualidade, a busca por alternativas para corrigir estes problemas e o grande potencial da terapia celular, tem levado inúmeros pesquisadores a ingressar nesta linha de estudo. No presente trabalho, buscou-se avaliar a influência da hidratação de implantes ósseos conservados em glicerina 98% sobre a resistência biomecânica dos mesmos; a viabilidade de um protocolo de colheita de medula óssea, para aplicação na rotina clínico-cirúrgica; e o efeito da aplicação intralesional da fração de células mononucleares da medula óssea, sobre a consolidação da interface enxerto-hospedeiro de cães submetidos à enxertia óssea segmentar, com implantes ósseos conservados em glicerina 98%. Esta pesquisa foi desenvolvida em duas fases. A primeira, ex-vivo, onde 108 fragmentos ósseos conservados em glicerina 98% foram separados em seis diferentes grupos, de acordo com o período de hidratação, sendo posteriormente submetidos a teste de compressão axial para avaliação de sua resistência biomecânica. A segunda fase, in-vivo, onde 20 cães sem raça definida e peso médio de 13kg, foram separados em quatro diferentes grupos de acordo com o tipo de enxerto empregado e com a aplicação ou não da fração de células mononucleares da medula óssea. Todos os animais foram submetidos a um protocolo de colheita de medula óssea, obtendo-se um volume final de 5ml kg-1 de peso corporal. A medula óssea colhida foi analisada por meio de mielograma e posteriormente submetida ao isolamento da fração de células mononucleares por técnica já consagrada na literatura. Um defeito ósseo femoral diafisário foi criado e reparado com o próprio segmento removido (grupos I e III) ou com um segmento ósseo conservado em glicerina 98% (grupos II e IV). A fração de células mononucleares da medula óssea, após isolamento, foi injetada por via intralesional nos cães dos grupos tratados (I e II), enquanto os grupos controle (III e IV) receberam a injeção do mesmo volume, porém, de solução de cloreto de sódio a 0,9%. A progressão da consolidação óssea das interfaces enxerto-hospedeiro foi acompanhada por exames radiográficos seriados até os 90 dias após a intervenção cirúrgica, enquanto a presença das células mononucleares, até os primeiros sete dias após a implantação, foi acompanhada pela detecção da fluorescência do nanocristal Qtracker-665, utilizado como marcador celular. De acordo com os resultado obtidos, pode-se concluir que: a hidratação do implante ósseo conservado em glicerina 98%, não produz alteração estatisticamente significativa na resistência biomecânica do osso cortical para os diferentes tempos avaliados. Contudo, a densidade mineral óssea possui estreita relação com esta propriedade; O protocolo de colheita de medula óssea em volume reduzido a 5ml kg-1 de peso corporal, obtidos de diferentes ossos longos, demonstrou-se adequado para isolamento da fração de células mononucleares e obtenção de um botão celular com adequado número de células e alta viabilidade, essenciais ao sucesso de sua aplicação terapêutica; a consolidação das interfaces enxerto-hospedeiro proximal e distal aos 90 dias após a cirurgia não apresentou diferença clínica e radiográfica entre os grupos controle e tratados com a fração de células mononucleares da medula óssea. Porém, não se pode afirmar que a terapia celular empregada neste estudo, não seja bom adjuvante da cicatrização óssea, pois se acredita, que a restrição na deposição de carga no foco de fratura, proveniente do reduzido exercício pós-operatório, tenha influenciado diretamente no resultado da consolidação.
Marques, Lins Esdras. "Membrana de biopolímero de cana-de-açúcar como remendo em arterioplastias femorais em cães." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/3198.
Повний текст джерелаObjetivo: O objetivo deste estudo foi avaliar a utilização da membrana de biopolímero de cana-de-açúcar como remendo em arterioplastias femorais em cães. Material e método: Oito cães adultos mestiços foram anestesiados por via endovenosa com cloridrato de cetamina na dose de 2,5 mg / Kg e brometo de pancurônio na dose de 0,2 mg / Kg, após indução com tiopental sódico na dose de 12,5 mg / Kg. Foi realizada tricotomia das regiões inguinais e a seguir procedeu-se a velocimetria Doppler percutânea das artérias femorais direita e esquerda para controle pré-operatório. Sob condições de assepsia e anti-sepsia os cães foram submetidos à dissecção das artérias femorais seguida da medida do diâmetro arterial e de uma arteriotomia longitudinal com retirada de um fragmento elíptico da parede arterial medindo 1,5 cm por um terço do diâmetro da artéria. Para a correção do defeito da parede arterial, os animais foram submetidos à arterioplastia femoral bilateral com remendos da membrana de biopolímero de cana-de-açúcar no lado esquerdo (grupo experimental) e de PTFE expandido (grupo controle) no lado direito. As suturas foram contínuas com fio de prolene ® 7.0. As membranas utilizadas como remendos são constituídas de um biopolímero obtido por síntese bacteriana a partir do melaço de cana-de-açúcar, produzidas na Estação Experimental de Cana-de-Açúcar de Carpina da Universidade Federal Rural de Pernambuco e processadas para aplicação como prótese cirúrgica no Núcleo de Cirurgia Experimental do Centro de Ciências da Saúde da Universidade Federal de Pernambuco. Na primeira semana pós-operatória os cães foram submetidos a avaliação clínica diária e semanal a partir do oitavo dia. A avaliação clínica consistiu no exame dos pulsos femorais, na avaliação da marcha e na observação da presença de tumor pulsátil, hematoma ou hemorragia e infecção da ferida operatória. Após 180 dias das arterioplastias, sob anestesia geral, foi realizada tricotomia das regiões inguinais e abdominal e procedeu-se nova fluxometria Doppler percutânea das artérias femorais . Os animais foram submetidos à dissecção das artérias femorais, medido o diâmetro arterial e realizada velocimetria Doppler trans-operatória em pontos proximal e distal à arterioplastia. A seguir foi realizada laparotomia e exposição da aorta abdominal para acesso arteriográfico. Através da velocimetria Doppler e da arteriografia foi pesquisada a ocorrência de trombose, aneurisma e falso-aneurisma. Os segmentos das artérias femorais com os remendos foram retirados para estudo histopatológico e os animais foram mortos com dose tóxica de anestésico. Resultados: No período de avaliação de 180 dias, nos dois grupos, não foram observados casos de infecção da ferida operatória , dilatação, ruptura, falso-aneurisma ou trombose. Nos dois grupos foi encontrada uma resposta inflamatória crônica com neutrófilos e linfócitos. Nas superfícies externa e interna dos remendos foi encontrada fibrose. No grupo controle ocorreu invasão dos remendos de e-PTFE por fibroblastos. Conclusões: Com base nos resultados obtidos com o modelo experimental utilizado, conclui-se que a membrana de biopolímero de cana-de-açúcar pode ser utilizada como remendo em arterioplastias femorais em cães
Carrillo, Luis Ramon Virgen. "Estudo piloto do impacto da terapia antiproliferativa com everolimus administrado por via oral na diminuição de reestenose após implante de stent auto-expansível de nitinol para tratamento de lesões oclusivas da artéria femoral superficial." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-08092009-132807/.
Повний текст джерелаINTRODUCTION: The implantation of a self-expanding of nitinol stent in the treatment of femoropopliteal occlusive lesions has been associated with a poor outcome in a long term setting. Everolimus administered orally to inhibit restenosis of the stent was investigated recently in animals with good results, but its safety and efficacy has not been studied in humans. The purpose of this pilot study was to evaluate the impact of antiproliferative therapy with everolimus administered orally for 28 days in the reduction of restenosis after implantation of self-expandable nitinol stent for treatment of occlusive lesions of the superficial femoral artery. METHODS AND RESULTS: Thirty-four patients were recruited for this randomized, prospective study. The group that received oral Everolimus was consisted of 15 patients and the group that received no medication was 19 patients. The baseline characteristics and procedure were similar in both groups. All the patients had chronic lower limb ischemia and occlusion of the superficial femoral artery (mean of the lesion of 83.14 mm in the group without medication and 105 mm in the everolimus group). The primary objective of the study was to evaluate the reduction of the average percentage of the diameter of in-stent restenosis six months after angioplasty assessed by quantitative angiography. The in-stent mean percent diameter stenosis was 46.9% in the group treated with everolimus and 44.5% in the group that received no medication (p = 0.81). There were no serious side effects seen in either group in the clinical follow up at 24 months. There was no significant difference between groups in relation to clinical events. The primary patency, assisted primary and secondary in 24 months was 42%, 74% and 79% in the group without medication and 27%, 73% and 73% in the group treated with Everolimus. CONCLUSION: Everolimus administered orally for 28 consecutive days to stent implantation in high doses proves to be safe and well tolerated, with low rate of side effects, but it is not effective in reducing the average percentage of diameter of in-stent restenosis in patients with implantation of self-expandable nitinol stent in complex occlusive lesions of the superficial femoral artery.
ETTORE, PIERRE-PAUL. "Influence de l'etendue du revetement en hydroxyapatite sur la fixation des implants femoraux sur mesure non cimentes : etude radioclinique comparative de deux series homogenes portant sur 556 cas." Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX20702.
Повний текст джерелаSouza, Rodrigo de Lima e. "Qualidade da analgesia utilizando bloqueio femoral por injeção única com ropivacaína ou bupivacaína para as operações de reconstrução do ligamento cruzado anterior e de implante de prótese total de joelho." Universidade Federal de Minas Gerais, 2007. http://hdl.handle.net/1843/ECJS-779MNH.
Повний текст джерелаAs operações ortopédicas de grande porte têm como característica o difícil controle da dor pós-operatória. Nesse sentido, o bloqueio femoral (BF) tem sido utilizado, em diversos serviços no mundo, promovendo analgesia do membro inferior com eficiência, segurança e poucos efeitos colaterais. Baseando-se nisso, o presente estudo avaliou a qualidade da analgesia em 90 pacientes submetidos às operações de reconstrução do ligamento cruzado anterior (RLCA) e de implante de prótese total do joelho (IPTJ), sendo distribuídos, aleatoriamente, em três grupos: grupo ropivacaína, composto por 32 pacientes submetidos ao BF com ropivacaína a 0,25%; grupo bupivacaína, composto por 30 pacientes submetidos ao BF com bupivacaína a 0,25% e grupo-controle, composto por 28 pacientes que receberam analgesia oral e venosa intermitente com antiinflamatórios não esteróides e opióides, sem BF. De acordo com a escala verbal de dor, dor moderada ou intensa, avaliada em repouso, foi mais freqüente no grupo-controle do que nos grupos ropivacaína e bupivacaína, nos tempos T1 (até 6h após o BF; p = 0,002) e T2 (entre 6h e 10h após o BF; p = 0,001). Também durante o movimento, dor moderada ou intensa foi mais freqüente no grupo-controle do que nos grupos ropivacaína e bupivacaína, nos tempos T1 (p = 0,001) e T2 (p = 0,000). Já em relação à satisfação com a analgesia pós-operatória, o grupo-controle referiu menor satisfação comparando com os grupos ropivacaína e bupivacaína, nos tempos T2 (p = 0,001) e T3 (após 10h e até 24h após o BF; p = 0,047). No que diz respeito à necessidade de opióides, os pacientes do grupo- controle apresentaram, no tempo T2, maior consumo de opióides do que os pacientes dos grupos submetidos ao BF (p = 0,03). Conclui-se, portanto, que os pacientes submetidos ao BF por injeção única com bupivacaína a 0,25% ou ropivacaína a 0,25% apresentam melhor qualidade de analgesia e maior satisfação, comparando aos pacientes do grupo-controle, após as operações de RLCA e IPTJ. Entre os grupos ropivacaína e bupivacaína não se observa diferença em relação à qualidade e satisfação com a analgesia pósoperatória. Além disso, há maior duração do BF com bupivacaína em relação à ropivacaína (p < 0,05).
Schopper, Clemens Oliver [Verfasser]. "Biomechanical evaluation of the femoral neck fracture fixation technique with the new implant FNS in comparison to DHS Blade, DHS Screw with antirotation screw and Three Cannulated Screws / Clemens Schopper." Ulm : Universität Ulm, 2018. http://d-nb.info/1151938327/34.
Повний текст джерелаSchopper, Clemens [Verfasser]. "Biomechanical evaluation of the femoral neck fracture fixation technique with the new implant FNS in comparison to DHS Blade, DHS Screw with antirotation screw and Three Cannulated Screws / Clemens Schopper." Ulm : Universität Ulm, 2018. http://d-nb.info/1151938327/34.
Повний текст джерелаSequeira, Sara Raquel Marques. "Development of zirconia composites for orthopedic." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/21527.
Повний текст джерелаZircónia e alumina são biocerâmicos bastante conhecidos, e são usados principalmente em aplicações ortopédicas. Estes materiais têm sido aplicados em implantes de anca e joelho graças à reduzida taxa de desgaste e à excelente biocompatibilidade que apresentam. No entanto, estes cerâmicos apresentam também algumas limitações: a fragilidade da alumina ao impacto e a sensibilidade da zircónia ao envelhecimento. Devido a estas limitações, o objectivo passou por desenvolver implantes mais resistentes e com uma resposta inflamatória menos intensa. Surgiram, então, estudos de compósitos de zircónia e alumina. Neste estudo, foram desenvolvidas três diferentes composições de Alumina reforçada com Zircónia (ZTA) com 80 wt% a 90 wt% de alumina, e três composições de Zircónia reforçada com Alumina (ATZ) com 80 wt% a 90 wt% de zircónia. Foram usados dois tipos diferentes de zircónia estabilizada: zircónia estabilizada com 3 mol% de yttria (3YSZ) que foi usada nos compósitos ATZ, e zircónia estabilizada com 2 mol% de yttria (2YSZ) aplicada nos compósitos ZTA. A composição ATZ com o melhor conjunto de propriedades foi também testada com a zircónia 2YSZ, de forma a produzir um compósito com melhores propriedades mecânicas e uma resistência à degradação semelhante à apresentada pelo compósito ATZ, com a zircónia 3YSZ. Foram seleccionados dois aditivos, óxido de lântanio e pentóxido de tântalo, que foram depois adicionados aos compósitos ATZ e ZTA com o melhor conjunto de propriedades (composição 80:20), com o objectivo de melhorar a resistência ao envelhecimento e as propriedades mecânicas dos materiais produzidos. Após uma etapa de moagem, os pós compósitos foram obtidos por atomização, a partir de suspensões estabilizadas, com uma distribuição de tamanho de partícula nanométrica controlada. Estes pós foram caracterizados através de várias técnicas tais como microscopia electrónica de varrimento, difracção de raios-X, fluorescência de raios-X, densidade real, e área superficial específica. De forma a aumentar a densidade dos corpos em verde, foram efectuadas duas diferentes prensagens, prensagem uniaxial e prensagem isostática a frio (CIP). Foram obtidos cerâmicos com uma elevada densidade (com densidade relativa entre 97% e 99%) a uma baixa temperatura de sinterização (1400ºC). O tamanho de grão das amostras sinterizadas foi observado por SEM e, de forma a verificar as fases cristalográficas presentes, foi realizada difracção de raios-X. Em todos os compósitos foi obtida uma microestrutura dispersa, com um tamanho de grão nanométrico (abaixo dos 500 nm). Este conjunto de etapas de produção aplicado levou à obtenção de compósitos com propriedades mecânicas melhoradas. Foram estudadas a dureza de Vickers, a tenacidade à fratura e resistência à flexão das amostras sinterizadas. Os compósitos ATZ atingiram os melhores valores de tenacidade à fractura e resistência à flexão (acima de 5 MPa.m1/2 e 1394 MPa respetivamente), enquanto os compósitos ZTA apresentaram os melhores valores de dureza (acima de 1846 HV). Como era esperado, o compósito ATZ com zircónia 2YSZ apresentou melhores propriedades mecânicas, tendo sido obtidos 7.94 MPa.m1/2 de tenacidade à fratura e 1498 MPa para a resistência à flexão. A aplicação dos dopantes nos compósitos ZTA e ATZ induziram alterações nas suas propriedades. A adição de Ta2O5 melhorou, com sucesso, as propriedades mecânicas dos dois tipos de compósitos. Foi verificado um aumento dos valores de dureza, tenacidade à fratura e resistência à flexão em relação às amostras sem dopantes. A adição de La2O3 não levou a melhorias nas propriedades mecânicas mas, no entanto, também não teve um efeito prejudicial, o que levou à sua preservação. Foram realizados testes de envelhecimento de acordo com a norma ISO13356 (2008) em todos os compósitos produzidos. A quantidade de zircónia monoclínica, indicador de degradação, foi determinada por difracção de raios-X após 5,12,24,48 e 96 horas de testes de envelhecimento. Foi determinado que os compósitos ZTA não dopados, não apresentaram zircónia monoclínica após 96 horas em ambiente agressivo. Para os compósitos ATZ, apesar de a quantidade de zircónia monoclínica aumentar proporcionalmente ao conteúdo de zircónia presente no compósito, foi verificado que a extensão da degradação foi mínima, e relegada apenas para a superfície do material. Esta evidência permitiu que as propriedades mecânicas se mantivessem durante todo o período dos testes de degradação. Como era esperado, o compósito com a zircónia menos estável, o ATZ com a zircónia 2YSZ, apresentou o conteúdo mais elevado de zircónia monoclínica. No entanto, o facto de as propriedades mecânicas se manterem ao longo dos testes de degradação, confirmou que a degradação, mais uma vez, não se expandiu para o interior do material. A adição dos dois dopantes levou a melhorias na resistência à degradação dos compósitos ATZ, que apresentaram um conteúdo de zircónica monoclínica menor em comparação com as amostras não dopadas, após 96 horas de testes de degradação. No entanto, a adição de Ta2O5 teve um efeito desestabilizador na zircónia 2YSZ presente no compósito ZTA, sendo que foi detectada 10% de zircónia monoclínica após as 96 horas de testes de degradação. De novo, foi confirmado que esta degradação esteve presente apenas à superfície do material, visto que as propriedades mecânicas se mantiveram após estes testes. Foi também testada a biocompatibilidade destes compósitos. Células MG63 foram cultivadas nas amostras sinterizadas e foram realizados ensaios MTT e ensaios de atividade da fosfatase alcalina. Para todos os compósitos produzidos foi verificado que a viabilidade/proliferação celular aumentou significativamente desde o dia 1 para o dia 4. Os compósitos ZTA, que possuíam um maior número de locais de adesão, apresentaram uma maior adesão e proliferação celular, em comparação com os compósitos ATZ. A adição de La2O3 e Ta2O5 não induziu diferenças significativas na viabilidade celular dos compósitos ATZ. No entanto, no compósito ZTA, a adição de Ta2O5 levou a um pior desempenho devido à sua verificada hidrofobicidade. O presente estudo mostra que podem ser obtidas composições óptimas destes compósitos, com excelentes propriedades mecânicas, resistência à degradação e biocompatibilidade satisfatória.
Zirconia and alumina are well known bioceramics, used in the field of orthopedics. These materials have been used as hip and knee bearings thanks to their reduced wear rate and excellent biocompatibility. However, these ceramics presented some limitations: the brittleness of alumina and the aging sensitivity of zirconia. The aim became to develop long-lasting hip implants, with less inflammatory response and better designs. Zirconia alumina composites were then studied. In this study, three different grades of alumina toughened zirconia composites (ATZ) from 80 wt% to 90 wt% of zirconia, and three grades of zirconia toughened alumina (ZTA) from 80 wt% to 90 wt% of alumina were developed. Two different types of stabilized zirconia were used: 3 mol% yttria stabilized zirconia (3YSZ) was applied on the ATZ samples, and a 2 mol% yttria stabilized zirconia (2YSZ) on the ZTA samples. The ATZ with the best set of properties (80Z20A) was also tested with the 2YSZ, in order to produce a composite with improved mechanical properties and similar aging resistance to the ATZ with 3YSZ. Two selected additives, lanthanum oxide and tantalum pentoxide were added to the best ATZ and ZTA composite (80:20 composition) with the aim of enhance the aging resistance and mechanical properties of the produced materials. After a wet milling stage, the composite powders were achieved by spray-drying, from stabilized suspensions with a controlled nanometric particle distribution. The obtained composite powders were characterized through several techniques, such as scanning electron microscopy, X-ray diffraction, X-ray fluorescence, true density and specific surface area. Two stages of pressing, uniaxial pressing and cold isostatic pressing, were performed in order to improve the density of the green pieces. High density ceramics (with a relative density between 97% and 99%) were achieved with a low sintering temperature (1400ºC). The grain size of the sintered pieces was determined by SEM, and X-ray diffraction was performed in order to verify the present crystallographic phases. A disperse microstructure was obtained for all composites, with a nanometric grain size (under 500 nm). This set of producing stages, lead to the obtention of composites with enhanced mechanical properties. The Vickers Hardness, fracture toughness and flexural strength of the sintered samples were evaluated. Higher values of fracture toughness and flexural strength were achieved for the ATZ samples (up to 5 MPa.m1/2 and 1394 MPa respectively), while ZTA samples presented higher values of hardness (up to 1846 HV). As expected, the ATZ with 2YSZ presented enhanced mechanical properties, with an outstanding fracture toughness of 7.94 MPa.m1/2, and 1498 MPa of flexural strength. The addition of the two dopants to both ZTA and ATZ composites induced changes in their properties. The addition of Ta2O5 successfully improved the mechanical properties of both composites. In comparison with the undoped ATZ and ZTA composites, improvements of the hardness, fracture toughness and flexural strength were verified. The addition of La2O3 did not lead to an enhancement of the mechanical properties; however, it did not led to a deleterious effect either, and these properties were maintained. Accelerated aging tests were made on all produced composites, accordingly to ISO13356 (2008). The amount of monoclinic zirconia, which is an indicator of degradation on these composites, was quantified by X-ray diffraction analysis for 5,12,24,48 and 96 hours of aging tests. It was determined that, the undoped ZTA samples did not present monoclinic zirconia after 96 hours on an aggressive environment. Regarding the ATZ composites, even though the monoclinic zirconia content increased proportionally to the zirconia content present in the composite, it was found that the extent of degradation was minimal, since it was relegated to the material surface. This fact allowed the maintaining of the mechanical properties of the material throughout all the duration of the aging tests. As expected, the less stable composite, the ATZ with 2YSZ, presented the highest content of monoclinic zirconia. Nonetheless, the mechanical properties tested on the aged composite confirmed that the degradation did not expand to the material bulk. The addition of both dopants, successfully improved the aging resistance of the ATZ composite, presenting a lower amount of monoclinic zirconia after 96 hours of aging tests in comparison with the undoped ones. However, the addition of Ta2O5 destabilized the 2YSZ present on the ZTA composites, and 10% of monoclinic zirconia was detected after 96 hours of aging tests. Still, the mechanical properties were maintained on all the doped composites, which again confirmed the presence of degradation only at the material surface. The biocompatibility of these composites was also tested. MG63 cells were seeded on the sintered samples and MTT and alkaline phosphatase activity (ALP) assays were performed. The cell viability/proliferation increased significantly from day 1 to day 4 for all the produced composites. The ZTA composites, with more anchorage sites, presented higher cell adhesion and proliferation in comparison with the ATZ composites. The addition of La2O3 and Ta2O5 did not induced significant changes on the cell viability of the ATZ composites. However, the addition of Ta2O5 on the ZTA composite led to a poor performance, due to its verified hydrophobicity. The present study shows that optimal compositions of these composites can be achieved, with improved mechanical properties, hydrothermal degradation resistance and satisfactory biocompatibility.
Seel, Matthias. "Ergebnissse nach arthroskopisch assistiert durchgeführter vorderer Kreuzbandplastik mit Semitendinosussehne als Triple-Implantat in Single-Incision-Technik und femoraler Endobutton-Fixation Nachuntersuchungen über einen Zeitraum von einem Jahr /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=970726953.
Повний текст джерелаDubory, Arnaud. "Interface os-implant titane et ingénierie tissulaire A cadaveric validation of a method based on impact analysis to monitor the femoral stem insertion Bone marrow mesenchymal stem cells predict radiographic osseointegration of cementeless titanium hip cups Survival, adhesion, and expression of osteoblastic genes of human derived-bone marrow mesenchymal stromal cells on PEEK and titanium-coated PEEK lumbar interbody cages." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC0067.
Повний текст джерелаIntroduction: Titanium, both used as a mean of fixing an implant to its biomechanical properties close to the bone and as a mean of osseointegration has taken a prominent place. The implant stability is essential for the durability of a titanium implant (TI); it depends on 2 phases: a primary phase, MECHANICAL, corresponding to the impaction or primary holding of the TI and a secondary phase, BIOLOGICAL, corresponding to the colonization of TI by bone tissue.The objective of this work was to evaluate and improve during these two phases the osseointegration of the titanium implant:(1) To evaluate the primary stability of uncemented titanium femoral stems by impact analysis corresponding to the measurement of impact over time.(2) To evaluate whether the amount of mesenchymal stromal cells (MSCs) contained in the iliac crest is correlated with the non-recovery survival of acetabular implants impacted in a context of aseptic osteonecrosis of the femoral head.(3) To improve the osseointegration of TI by cell therapy methods in vitro by studying the survival and division of human MSCs in contact with interbody lumbar cages coated with rough titanium alloy.Methods: The evaluation of the primary stability of cementless titanium femoral stems according to the impact analysis was carried out using a hammer equipped with a piezoelectric force sensor on 20 anatomical subjects, i.e. 40 hips. The number of hammer strokes was compared to obtain the ideal impaction of the prosthesis according to 3 different evaluation methods: number of impacts required by the surgeon (Nsurg), number of impacts required by the video analysis of the depression of the stem in the femur (Nvid), numbers of impacts needed by the impact analysis (Ni).To determine whether the amount of MSCs in the iliac crest could reflect the osseointegration of impacted acetabular implants and the risk of surgical revision. The rate of MSCs measured when performing a surgical cell therapy for aseptic osteonecrosis of the femoral head and the clinical and radiographic outcome of acetabular implants subsequently established for these same patients (n = 90), who had total hip arthroplasty in fine were compared. The mean follow-up was 15 years.The cell survival of bone marrow-derived MSCs was evaluated on lumbar interbody cages coated with titanium. Three groups (n = 5) were formed: a control group, a cage group with titanium surface, a cage group without titanium. On each implant, 1 microliter containing 106 human bone MSCs was cultured. The analysis of cell survival, cell proliferation and expression of osteoblastic genes were performed and compared.Results: Regarding the impact analysis of the cementless femoral stem impaction, the difference between NI, Nchir and Nvid was lower than 3 for more than 85% of the configurations performed.For the second study, a small number of MSCs in the iliac crest was a risk factor for surgical revision in patients treated with a cementless acetabular implant.The third study showed that MSCs could grow until 96 hours and could express osteoblastics genes 21 days after cell seed. No difference between PEEK cage and Titanium-coated PEEK has been found.Conclusion: The impact analysis provides objective data on the primary holding of the titanium impacted femoral stem. Titanium is also a favored biomaterial for the survival and proliferation of bone marrow-derived MSC predestined to become osteforming cells, especially since a small number of MSCs seems to be a risk of failure of osseointegration of cementless acetabular implants
Lin, Bing-You, and 林炳佑. "Design Improvements and Mechanical Evaluations of Orthopaedic Implants for Proximal Femoral Fractures." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/5hweba.
Повний текст джерела國立臺灣科技大學
機械工程系
99
There are two main methods of the operative treatment of proximal femoral fractures, one is intramedullary, and the other one is extramedullary. Gamma nail (GN) is the standard treatment of intramedullary fixation, and the Dynamic hip screw (DHS) is the standard treatment of extramedullary fixation. These two fracture fixation devices are widely used in the treatment of proximal femoral fractures, but clinical failures of those implants are still to be found. So there were many studies to propose the improved designs to reduce the risk of implant failure for the DHS and GN. The purpose of this study is to develop three-dimensional finite element models to investigate and improve the biomechanical performances of GN and DHS. The FEM was used to evaluate the improvement of DHS and GN in the biomechanical performances under three types of the proximal femoral fractures (neck fracture, subtrochanteric fracture, and subtrochanteric fracture with gap).Improvement of the DHS is increasing length of bone plate, using the locking or non-locking bone plates, and increasing diameter of distal screw. Improvement of GN is increasing length of nail, and increasing length of nail tip. The maximum distortion energy criterion and the maximum deflection criterion were used to discuss the merits of their biomechanical implant performance. Finally, this study will also compare optimum improvement of DHS and GN with DSN. The results showed that DHS with longest length, will increase the risk of the implant failure, but the fracture fixation stability will enhance. However, maximal von Mises stress was found in the distal screw. So the diameter of the distal locking screw was increased to reduce the stress. The above improvement (ILDHS) could increase the stability of fracture fixation and reduce the risk of implant failure. The isthmus can protect the Gamma Nail as the long Gamma nail (LGN) was designed. So the risk of implant failure and the fracture fixation stability can be improved simultaneously. This study showed that the improved designs have greater biomechanical performance in the neck fracture and subtrochanteric fracture. However, in subtrochanteric fracture with gap fracture the risk of implant failure and the fixation stability of ILDHS were inferior to that of the LGN and DSN. It can be speculated that for unstable fractures intramedullary implants are superior than extramedullary implants.
Wang, Allan W. (Allan Wen Li). "Femoral bone remodelling following cemented hip arthroplasty in a sheep model / Allan W. Wang." 1998. http://hdl.handle.net/2440/19343.
Повний текст джерелаxii, 219 leaves : ill. (chiefly col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Examines the effect of implant design on the femoral bone remodelling response in a sheep cemented hip arthroplasty model. The clinical section of the thesis also indicates the importance of biological factors in the femoral bone remodelling response.
Thesis (Ph.D.)--University of Adelaide, Dept. of Orthopaedics and Trauma, 1998
Wang, Allan W. (Allan Wen Li). "Femoral bone remodelling following cemented hip arthroplasty in a sheep model / Allan W. Wang." Thesis, 1998. http://hdl.handle.net/2440/19343.
Повний текст джерелаxii, 219 leaves : ill. (chiefly col.) ; 30 cm.
Examines the effect of implant design on the femoral bone remodelling response in a sheep cemented hip arthroplasty model. The clinical section of the thesis also indicates the importance of biological factors in the femoral bone remodelling response.
Thesis (Ph.D.)--University of Adelaide, Dept. of Orthopaedics and Trauma, 1998
Brumby, Scott Andrew. "The effect of surface roughness and a collar on fixation of cemented femoral stems in vivo / by Scott Andrew Brumby." Thesis, 1996. http://hdl.handle.net/2440/18921.
Повний текст джерелаxiii, 206 leaves : ill. (chiefly col.) ; 30 cm.
This thesis investigates the effect of femoral stem surface roughness and a collar on the fixation of cemented hip hemi-arthroplasty femoral stems in an in vivo sheep model up to nine months following implantation. Plain radiography, micromotion between prosthesis and bone during mechanical testing and histology are used.
Thesis (Ph.D.)--University of Adelaide, Dept. of Orthopaedics and Trauma, 1997?
Olsen, Michael. "Optimizing Femoral Head Preparation in Hip Resurfacing Arthroplasty." Thesis, 2009. http://hdl.handle.net/1807/26474.
Повний текст джерелаSeel, Matthias [Verfasser]. "Ergebnissse nach arthroskopisch assistiert durchgeführter vorderer Kreuzbandplastik mit Semitendinosussehne als Triple-Implantat in Single-Incision-Technik und femoraler Endobutton-Fixation : Nachuntersuchungen über einen Zeitraum von einem Jahr / vorgelegt von Matthias Seel." 2004. http://d-nb.info/970726953/34.
Повний текст джерела