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[PMID]:28278776
[Au] Autor:Sreeda P; Sathya AB; Sivasubramanian V
[Ad] Endereço:a Department of Chemical Engineering , National Institute of Technology Calicut, Kozhikode , Kerala , India.
[Ti] Título:Novel application of high-density polyethylene mesh as self-forming dynamic membrane integrated into a bioreactor for wastewater treatment.
[So] Source:Environ Technol;39(1):51-58, 2018 Jan.
[Is] ISSN:0959-3330
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:In the present study, self-forming dynamic membrane (SFDM) on rigid high-density polyethylene (HDPE) mesh with a large pore size of 2 mm is reported for the first time. The system was investigated for utilisation in simulated wastewater treatment by integrating the mesh with an aerobic bioreactor. The SFDM was analysed using Fourier transform infra-red (FT-IR) spectroscopy and visualised by scanning electron microscopy (SEM). The effect of the operating parameter on the change in composition of SFDM was also investigated. The system was used as a single unit for treatment of wastewater and showed stability over long-term treatment. The system could achieve a chemical oxygen demand (COD) reduction of 82.16 ± 6.47% at an influent COD concentration of 613.93 ± 72.13 mg/l and ammonia removal efficiency of 97.21 ± 0.62% at an influent ammonia concentration of 55.54 ± 2.23 mg/l. The reactor generated high-quality effluent and the turbidity recorded was less than 2NTU. In addition, the operational parameters, namely hydraulic retention time and organic loading rate, were optimised.
[Mh] Termos MeSH primário: Reatores Biológicos
Filtração/instrumentação
Polietileno/química
Eliminação de Resíduos Líquidos/métodos
[Mh] Termos MeSH secundário: Espectroscopia de Infravermelho com Transformada de Fourier
Águas Residuais/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Waste Water); 9002-88-4 (Polyethylene)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180308
[Lr] Data última revisão:
180308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170311
[St] Status:MEDLINE
[do] DOI:10.1080/09593330.2017.1294623


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[PMID]:29437054
[Au] Autor:Hexter AT; Hislop SM; Blunn GW; Liddle AD
[Ad] Endereço:Institute of Orthopaedics and Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
[Ti] Título:The effect of bearing surface on risk of periprosthetic joint infection in total hip arthroplasty: a systematic review and meta-analysis.
[So] Source:Bone Joint J;100-B(2):134-142, 2018 Feb.
[Is] ISSN:2049-4408
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:AIMS: Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty (THA). Different bearing surface materials have different surface properties and it has been suggested that the choice of bearing surface may influence the risk of PJI after THA. The objective of this meta-analysis was to compare the rate of PJI between metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC) bearings. PATIENTS AND METHODS: Electronic databases (Medline, Embase, Cochrane library, Web of Science, and Cumulative Index of Nursing and Allied Health Literature) were searched for comparative randomized and observational studies that reported the incidence of PJI for different bearing surfaces. Two investigators independently reviewed studies for eligibility, evaluated risk of bias, and performed data extraction. Meta-analysis was performed using the Mantel-Haenzel method and random-effects model in accordance with methods of the Cochrane group. RESULTS: Our search strategy revealed 2272 studies, of which 17 met the inclusion criteria and were analyzed. These comprised 11 randomized controlled trials and six observational studies. The overall quality of included studies was high but the observational studies were at high risk of bias due to inadequate adjustment for confounding factors. The overall cumulative incidence of PJI across all studies was 0.78% (1514/193 378). For each bearing combination, the overall incidence was as follows: MoP 0.85% (1353/158 430); CoP 0.38% (67/17 489); and CoC 0.53% (94/17 459). The meta-analysis showed no significant difference between the three bearing combinations in terms of risk of PJI. CONCLUSION: On the basis of the clinical studies available, there is no evidence that bearing choice influences the risk of PJI. Future research, including basic science studies and large, adequately controlled registry studies, may be helpful in determining whether implant materials play a role in determining the risk of PJI following arthroplasty surgery. Cite this article: 2018;100-B:134-42.
[Mh] Termos MeSH primário: Artroplastia de Quadril
Prótese de Quadril
Infecções Relacionadas à Prótese/etiologia
[Mh] Termos MeSH secundário: Cerâmica
Seres Humanos
Incidência
Metais
Polietileno
Desenho de Prótese
Infecções Relacionadas à Prótese/epidemiologia
Fatores de Risco
Propriedades de Superfície
[Pt] Tipo de publicação:JOURNAL ARTICLE; META-ANALYSIS; REVIEW
[Nm] Nome de substância:
0 (Metals); 9002-88-4 (Polyethylene)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180216
[Lr] Data última revisão:
180216
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:180214
[St] Status:MEDLINE
[do] DOI:10.1302/0301-620X.100B2.BJJ-2017-0575.R1


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[PMID]:29182016
[Au] Autor:Wang D; Wu X; Long L; Yuan X; Zhang Q; Xue S; Wen S; Yan C; Wang J; Cong W
[Ad] Endereço:a School of Food Engineering and Biological Technology , Tianjin University of Science & Technology , Tianjin , P.R. China.
[Ti] Título:Improved antifouling properties of photobioreactors by surface grafted sulfobetaine polymers.
[So] Source:Biofouling;33(10):970-979, 2017 11.
[Is] ISSN:1029-2454
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:To improve the antifouling (AF) properties of photobioreactors (PBR) for microalgal cultivation, using trihydroxymethyl aminomethane (tris) as the linking agent, a series of polyethylene (PE) films grafted with sulfobetaine (PE-SBMA) with grafting density ranging from 23.11 to 112 µg cm were prepared through surface-initiated atom transfer radical polymerization (SI-ATRP). It was found that the contact angle of PE-SBMA films decreased with the increase in the grafting density. When the grafting density was 101.33 µg cm , it reached 67.27°. Compared with the PE film, the adsorption of protein on the PE-SBMA film decreased by 79.84% and the total weight of solid and absorbed microalgae decreased by 54.58 and 81.69%, respectively. Moreover, the transmittance of PE-SBMA film recovered to 86.03% of the initial value after cleaning, while that of the PE film recovered to only 47.27%. The results demonstrate that the AF properties of PE films were greatly improved on polySBMA-grafted surfaces.
[Mh] Termos MeSH primário: Betaína/análogos & derivados
Incrustação Biológica/prevenção & controle
Microalgas/efeitos dos fármacos
Fotobiorreatores
[Mh] Termos MeSH secundário: Adsorção
Betaína/farmacologia
Microalgas/fisiologia
Polietileno/química
Polímeros/química
Polímeros/farmacologia
Proteínas
Propriedades de Superfície
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Polymers); 0 (Proteins); 3SCV180C9W (Betaine); 8CVU22OCJW (sulfobetaine); 9002-88-4 (Polyethylene)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180215
[Lr] Data última revisão:
180215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171129
[St] Status:MEDLINE
[do] DOI:10.1080/08927014.2017.1394457


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[PMID]:28462822
[Au] Autor:Moon KC; Lee JS; Han SK; Lee HW; Dhong ES
[Ad] Endereço:Department of Plastic Surgery, Korea University College of Medicine, Seoul, South Korea.
[Ti] Título:Effects of human umbilical cord blood-derived mesenchymal stromal cells and dermal fibroblasts on diabetic wound healing.
[So] Source:Cytotherapy;19(7):821-828, 2017 07.
[Is] ISSN:1477-2566
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND AIMS: A previous study demonstrated that human umbilical cord blood-derived mesenchymal stromal cells (hUCB-MSCs) have superior wound-healing activity compared with fibroblasts in vitro. However, wound healing in vivo is a complex process that involves multiple factors. The purpose of this study was to compare the effects of hUCB-MSCs and fibroblasts on diabetic wound healing in vivo. This study especially focused on collagen synthesis and angiogenesis, which are considered to be the important factors affecting diabetic wound healing. METHODS: Porous polyethylene discs were loaded with either fibroblasts or hUCB-MSCs, and a third group, which served as a control, was not loaded with cells. The discs were then implanted in the back of diabetic mice. During the first and the second week after implantation, the discs were harvested, and collagen level and microvascular density were compared. RESULTS: In terms of collagen synthesis, the hUCB-MSC group showed the highest collagen level (117.7 ± 8.9 ng/mL), followed by the fibroblast group (83.2 ± 5.2 ng/mL) and the no-cell group (60.0 ± 4.7 ng/mL) in the second week after implantation. In terms of angiogenesis, the microvascular density in the hUCB-MSC group was 56.8 ± 16.4, which was much higher than that in the fibroblast group (14.3 ± 4.0) and the no-cell group (5.7 ± 2.1) in the second week after implantation. CONCLUSIONS: These results demonstrate that hUCB-MSCs are superior to fibroblasts in terms of their effect on diabetic wound healing in vivo.
[Mh] Termos MeSH primário: Complicações do Diabetes/terapia
Sangue Fetal/citologia
Transplante de Células-Tronco Mesenquimais/métodos
Cicatrização/fisiologia
[Mh] Termos MeSH secundário: Animais
Colágeno/metabolismo
Diabetes Mellitus Experimental/complicações
Fibroblastos/transplante
Seres Humanos
Células Mesenquimais Estromais/fisiologia
Camundongos Endogâmicos C57BL
Polietileno
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
9002-88-4 (Polyethylene); 9007-34-5 (Collagen)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180212
[Lr] Data última revisão:
180212
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170503
[St] Status:MEDLINE


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[PMID]:29305447
[Au] Autor:Goodnough LH; Bala A; Huddleston J; Goodman SB; Maloney WJ; Amanatullah DF
[Ad] Endereço:Stanford University, 450 Broadway Street, Redwood City, California, 94063, USA.
[Ti] Título:Metal-on-metal total hip arthroplasty is not associated with cardiac disease.
[So] Source:Bone Joint J;100-B(1):28-32, 2018 01.
[Is] ISSN:2049-4408
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:AIMS: Many case reports and small studies have suggested that cobalt ions are a potential cause of cardiac complications, specifically cardiomyopathy, after metal-on-metal (MoM) total hip arthroplasty (THA). The impact of metal ions on the incidence of cardiac disease after MoM THA has not been evaluated in large studies. The aim of this study was to compare the rate of onset of new cardiac symptoms in patients who have undergone MoM THA with those who have undergone metal-on-polyethylene (MoP) THA. PATIENTS AND METHODS: Data were extracted from the Standard Analytics Files database for patients who underwent MoM THA between 2005 and 2012. Bearing surface was selected using International Classification of Diseases ninth revision codes. Patients with a minimum five-year follow-up were selected. An age and gender-matched cohort of patients who underwent MoP THA served as a comparison group. New diagnoses of cardiac disease were collected during the follow-up period. Comorbidities and demographics were identified and routine descriptive statistics were used. RESULTS: We identified 29 483 patients who underwent MoM THA and 24 175 matched patients who underwent MoP THA. Both groups had a mean Charlson comorbidity index score of 4. There were no statistically significant differences in 30 of 31 pre-existing comorbidities. Patients undergoing MoM THA had a slightly lower incidence of cardiac failure compared with those undergoing MoP THA at three years (6.60% 7.06%, odds ratio (OR) 0.93, 95% confidence interval (CI) 0.87 to 0.99) and four years (8.73% 9.49%, OR 0.91, 95% CI 0.86 to 0.97) postoperatively, with no difference in the incidence of new cardiac failure in between the groups at five years. There was no statistically significant difference in the incidence of arrhythmia, myocardial infarction and cardiomyopathy at any time between the two groups. CONCLUSION: MoM THA is not associated with cardiac complications. Initial reports may have represented individual instances of cardiac disease in patients with a failing MoM articulation rather than an emerging epidemiological trend. Cite this article: 2018;100-B:28-32.
[Mh] Termos MeSH primário: Artroplastia de Quadril/efeitos adversos
Cardiopatias/etiologia
Prótese de Quadril/efeitos adversos
Próteses Articulares Metal-Metal/efeitos adversos
[Mh] Termos MeSH secundário: Idoso
Idoso de 80 Anos ou mais
Artroplastia de Quadril/instrumentação
Comorbidade
Bases de Dados Factuais
Feminino
Cardiopatias/epidemiologia
Seres Humanos
Incidência
Masculino
Meia-Idade
Polietileno
Desenho de Prótese
Falha de Prótese/etiologia
Estados Unidos/epidemiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
9002-88-4 (Polyethylene)
[Em] Mês de entrada:1801
[Cu] Atualização por classe:180124
[Lr] Data última revisão:
180124
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:180107
[St] Status:MEDLINE
[do] DOI:10.1302/0301-620X.100B1.BJJ-2017-0366.R1


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[PMID]:29040124
[Au] Autor:Devane PA; Horne JG; Ashmore A; Mutimer J; Kim W; Stanley J
[Ad] Endereço:1Wellington Hospital, Wellington, New Zealand 2Great Western Hospital, Swindon, United Kingdom 3Cheltenham General Hospital, Cheltenham, United Kingdom 4University of Otago, Wellington, New Zealand.
[Ti] Título:Highly Cross-Linked Polyethylene Reduces Wear and Revision Rates in Total Hip Arthroplasty: A 10-Year Double-Blinded Randomized Controlled Trial.
[So] Source:J Bone Joint Surg Am;99(20):1703-1714, 2017 Oct 18.
[Is] ISSN:1535-1386
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Highly cross-linked polyethylene (XLPE) was developed to address the problem of wear and osteolysis associated with metal-on-conventional ultra-high molecular weight polyethylene (UHMWPE) bearing surfaces. The purpose of this study was to compare in vivo wear rates and clinical and radiographic outcomes between XLPE and UHMWPE in a prospective double-blinded randomized controlled trial with a minimum of 10 years of follow-up. METHODS: We randomized 122 patients to receive either a conventional UHMWPE liner (Enduron; DePuy) or an XLPE liner (Marathon; DePuy). Ninety-one patients were assessed clinically and radiographically at a minimum of 10 years (range, 10.08 to 12.17 years). Oxford Hip Scores and Short Form-12 Health Survey scores were collected. The radiographs were analyzed for osteolysis and for 2-dimensional (2-D), 3-dimensional (3-D), and volumetric wear using validated software. RESULTS: All 122 patients were accounted for at the 10-year follow-up evaluation. Twelve patients had undergone revision surgery, 21 patients had died (1 of whom had previously undergone revision surgery), and 2 patients were unable to return for follow-up, leaving 91 patients available for clinical and radiographic evaluation. At a minimum of 10 years, 3-D wear rates were significantly lower (p < 0.001) in the XLPE group (mean, 0.03 mm/yr) than in the conventional UHMWPE group (mean, 0.27 mm/yr). The prevalence of osteolysis was also significantly lower in the XLPE group (38% versus 8%, p < 0.005), as was the revision rate (14.6% versus 1.9%, p = 0.012), with 10 of the 12 revisions being in the Enduron group. There was no significant difference between the clinical scores of the 2 groups. CONCLUSIONS: XLPE liners have significantly reduced wear and are associated with a greater implant survival rate at 10 years compared with conventional UHMWPE liners. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
[Mh] Termos MeSH primário: Artroplastia de Quadril/instrumentação
Prótese de Quadril
Osteoartrite do Quadril/cirurgia
Polietileno
Desenho de Prótese
Falha de Prótese
Reoperação/estatística & dados numéricos
[Mh] Termos MeSH secundário: Idoso
Artroplastia de Quadril/estatística & dados numéricos
Reagentes para Ligações Cruzadas
Método Duplo-Cego
Feminino
Seguimentos
Seres Humanos
Estimativa de Kaplan-Meier
Masculino
Meia-Idade
Osteoartrite do Quadril/diagnóstico por imagem
Estudos Prospectivos
Resultado do Tratamento
[Pt] Tipo de publicação:JOURNAL ARTICLE; RANDOMIZED CONTROLLED TRIAL
[Nm] Nome de substância:
0 (Cross-Linking Reagents); 9002-88-4 (Polyethylene)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171102
[Lr] Data última revisão:
171102
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:171018
[St] Status:MEDLINE
[do] DOI:10.2106/JBJS.16.00878


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[PMID]:28963149
[Au] Autor:Devane PA; Horne JG; Foley G; Stanley J
[Ad] Endereço:Capital & Coast District Health Board, Private Bag 7902, Wellington South, New Zealand.
[Ti] Título:Measuring the migration of the components and polyethylene wear after total hip arthroplasty: beads and specialised radiographs are not necessary.
[So] Source:Bone Joint J;99-B(10):1290-1297, 2017 Oct.
[Is] ISSN:2049-4408
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:AIMS: This paper describes the methodology, validation and reliability of a new computer-assisted method which uses models of the patient's bones and the components to measure their migration and polyethylene wear from radiographs after total hip arthroplasty (THA). MATERIALS AND METHODS: Models of the patient's acetabular and femoral component obtained from the manufacturer and models of the patient's pelvis and femur built from a single computed tomography (CT) scan, are used by a computer program to measure the migration of the components and the penetration of the femoral head from anteroposterior and lateral radiographs taken at follow-up visits. The program simulates the radiographic setup and matches the position and orientation of the models to outlines of the pelvis, the acetabular and femoral component, and femur on radiographs. Changes in position and orientation reflect the migration of the components and the penetration of the femoral head. Validation was performed using radiographs of phantoms simulating known migration and penetration, and the clinical feasibility of measuring migration was assessed in two patients. RESULTS: Migration of the acetabular and femoral components can be measured with limits of agreement (LOA) of 0.37 mm and 0.33 mm, respectively. Penetration of the femoral head can be measured with LOA of 0.161 mm. CONCLUSION: The migration of components and polyethylene wear can be measured without needing specialised radiographs. Accurate measurement may allow earlier prediction of failure after THA. Cite this article: 2017;99-B:1290-7.
[Mh] Termos MeSH primário: Artroplastia de Quadril
Prótese de Quadril
Polietileno/química
Tomografia Computadorizada por Raios X/métodos
[Mh] Termos MeSH secundário: Materiais Revestidos Biocompatíveis/química
Estudos de Viabilidade
Feminino
Seres Humanos
Imagem Tridimensional
Masculino
Desenho de Prótese
Falha de Prótese
Propriedades de Superfície
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Coated Materials, Biocompatible); 9002-88-4 (Polyethylene)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171012
[Lr] Data última revisão:
171012
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:171001
[St] Status:MEDLINE
[do] DOI:10.1302/0301-620X.99B10.BJJ-2016-1169.R1


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[PMID]:28963148
[Au] Autor:Rajpura A; Board TN; Siney PD; Wynn Jones H; Williams S; Dabbs L; Wroblewski BM
[Ad] Endereço:Wrightington Hospital, Hall Lane, Appley Bridge, Wigan WN6 9EP, UK.
[Ti] Título:A 28-year clinical and radiological follow-up of alumina ceramic-on-crosslinked polyethylene total hip arthroplasty: a follow-up report and analysis of the oxidation of a shelf-aged acetabular component.
[So] Source:Bone Joint J;99-B(10):1286-1289, 2017 Oct.
[Is] ISSN:2049-4408
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:AIMS: Our aim in this study was to describe a continuing review of 11 total hip arthroplasties using 22.225 mm Alumina ceramic femoral heads on a Charnley flanged femoral component, articulating against a silane crosslinked polyethylene. PATIENTS AND METHODS: Nine patients (11 THAs) were reviewed at a mean of 27.5 years (26 to 28) post-operatively. Outcome was assessed using the d'Aubigne and Postel, and Charnley scores and penetration was recorded on radiographs. In addition, the oxidation of a 29-year-old shelf-aged acetabular component was analysed. RESULTS: The mean clinical outcome scores remained excellent at final follow-up. The mean total penetration remained 0.41 mm (0.40 to 0.41). There was no radiographic evidence of acetabular or femoral loosening or osteolysis. There was negligible oxidation in the shelf-aged sample despite gamma irradiation and storage in air. CONCLUSION: These results highlight the long-term stability and durability of this type of crosslinked, antioxidant containing polyethylene when used in combination with a small diameter alumina ceramic femoral head. Cite this article: 2017;99-B:1286-9.
[Mh] Termos MeSH primário: Acetábulo/diagnóstico por imagem
Óxido de Alumínio
Previsões
Prótese de Quadril
Polietileno
Complicações Pós-Operatórias/diagnóstico
Radiografia/métodos
[Mh] Termos MeSH secundário: Acetábulo/cirurgia
Adulto
Artroplastia de Quadril/métodos
Feminino
Seguimentos
Seres Humanos
Masculino
Meia-Idade
Estudos Prospectivos
Desenho de Prótese
Falha de Prótese
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
9002-88-4 (Polyethylene); LMI26O6933 (Aluminum Oxide)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171012
[Lr] Data última revisão:
171012
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:171001
[St] Status:MEDLINE
[do] DOI:10.1302/0301-620X.99B10.BJJ-2017-0105.R1


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[PMID]:28905208
[Au] Autor:Sisko ZW; Teeter MG; Lanting BA; Howard JL; McCalden RW; Naudie DD; MacDonald SJ; Vasarhelyi EM
[Ad] Endereço:Division of Orthopaedic Surgery, Department of Surgery, London Health Sciences Centre and the Schulich School of Medicine & Dentistry at Western University, University Hospital, London, ON, Canada. Zachary.Sisko@ahn.org.
[Ti] Título:Current Total Knee Designs: Does Baseplate Roughness or Locking Mechanism Design Affect Polyethylene Backside Wear?
[So] Source:Clin Orthop Relat Res;475(12):2970-2980, 2017 Dec.
[Is] ISSN:1528-1132
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Tibial baseplate roughness and polyethylene-insert micromotion resulting from locking-mechanism loosening can lead to polyethylene backside wear in TKAs. However, many retrieval studies examining these variables have evaluated only older TKA implant designs. QUESTIONS: We used implant-retrieval analysis to examine if there were differences in: (1) backside damage scores, (2) backside damage modes, and (3) backside linear wear rates in five TKA implant designs owing to differing baseplate surface roughness and locking mechanisms. Additionally, we examined if (4) patient demographics influence backside damage and wear. METHODS: Five TKA implant models (four modern and one historical design) were selected with different tibial baseplate and/or locking mechanism designs. Six tibial inserts retrieved at the time of revision from each TKA model were matched for time in vivo, age of the patient at TKA revision, BMI, sex, revision number, and revision reason. Each insert backside was analyzed for: (1) visual total damage score and (2) individual visual damage modes, both by two observers and with an intraclass correlation coefficient of 0.66 (95% CI, 0.39-0.92), and (3) linear wear rate measured by micro-CT. Median primary outcomes were compared among the five designs. For our given sample size among five groups we could detect with 80% power a 10-point difference in damage score and an 0.11-mm per year difference in wear rate. RESULTS: The polished tibial design with a partial peripheral capture locking mechanism and anterior constraint showed a lower total damage score compared with the nonpolished tibial design with only a complete peripheral-rim locking mechanism (median, 12.5; range, 9.5-18.0; 95% CI, 9.58-16.42 versus median, 22.3; range, 15.5-27.0; 95% CI, 17.5-26.5; p = 0.019). The polished baseplate with a tongue-in-groove locking mechanism showed more abrasions than the nonpolished baseplate with a peripheral-rim capture and antirotational island (median, 7.25; range, 0.5-8.0; 95% CI, 2.67-8.99 versus median, 0.75; range, 0-1.5; 95% CI, 0.20-1.47; p = 0.016)). Dimpling was a unique wear mode to the nonpolished baseplates with the peripheral-rim capture and antirotational island (median, 5.5; range, 2.0-9.0; 95% CI, 2.96-8.38) and the peripheral-rim capture alone (median, 9.0; range, 6.0-10.0; 95% CI, 7.29-10.38). Overall, the linear wear rate for polished designs was lower than for nonpolished designs (0.0102 ± 0.0044 mm/year versus 0.0224 ± 0.0119 mm/year; p < 0.001). Two of the polished baseplate designs, the partial peripheral capture with anterior constraint (median, 0.083 mm/year; range, 0.0037-0.0111 mm/year; 95% CI, 0.0050-0.0107 mm versus median, 0.0245 mm/year; range, 0.014-0.046 mm/year; 95% CI, 0.0130-0.0414 mm; p = 0.008) and the tongue-in-groove locking mechanism (median, 0.0085 mm/year; range, 0.005-0.015 mm/year; 95% CI, 0.0045-0.0138 mm; p = 0.032) showed lower polyethylene linear wear rates compared with the nonpolished baseplate design with only a peripheral-rim capture. CONCLUSIONS: Total damage scores and linear wear rates were highest involving the nonpolished design with only a peripheral rim capture. There were no differences among the other TKA designs regarding damage and wear, but this finding should be considered in the setting of a relatively small sample size. CLINICAL RELEVANCE: Our study showed that in the complex interplay between baseplate surface finish and locking mechanism design, a polished baseplate with a robust locking mechanism had the lowest backside damage and linear wear. However, improvements in locking mechanism design in nonpolished baseplates potentially may offset some advantages of a polished baseplate. Further retrieval analyses need to be done to confirm such findings, especially analyzing current crosslinked polyethylene. Additionally, we need mid- and long-term studies comparing TKA revisions attributable to wear and osteolysis among implants before understanding if such design differences are clinically relevant.
[Mh] Termos MeSH primário: Artroplastia do Joelho/instrumentação
Articulação do Joelho/cirurgia
Prótese do Joelho
Polietileno/química
Desenho de Prótese
Falha de Prótese
[Mh] Termos MeSH secundário: Idoso
Artroplastia do Joelho/efeitos adversos
Fenômenos Biomecânicos
Remoção de Dispositivo
Feminino
Seres Humanos
Articulação do Joelho/diagnóstico por imagem
Articulação do Joelho/fisiopatologia
Masculino
Meia-Idade
Fatores de Risco
Estresse Mecânico
Propriedades de Superfície
Fatores de Tempo
Resultado do Tratamento
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
9002-88-4 (Polyethylene)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171117
[Lr] Data última revisão:
171117
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:170915
[St] Status:MEDLINE
[do] DOI:10.1007/s11999-017-5494-3


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[PMID]:28884275
[Au] Autor:Pourzal R; Hall DJ; Ehrich J; McCarthy SM; Mathew MT; Jacobs JJ; Urban RM
[Ad] Endereço:Department of Orthopedic Surgery, Rush University Medical Center, 1611 W Harrison Street, Suite 204-H, Chicago, IL, 60612, USA. robin_pourzal@rush.edu.
[Ti] Título:Alloy Microstructure Dictates Corrosion Modes in THA Modular Junctions.
[So] Source:Clin Orthop Relat Res;475(12):3026-3043, 2017 Dec.
[Is] ISSN:1528-1132
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Adverse local tissue reactions (ALTRs) triggered by corrosion products from modular taper junctions are a known cause of premature THA failure. CoCrMo devices are of particular concern because cobalt ions and chromium-orthophosphates were shown to be linked to ALTRs, even in metal-on-polyethylene THAs. The most common categories of CoCrMo alloy are cast and wrought alloy, which exhibit fundamental microstructural differences in terms of grain size and hard phases. The impact of implant alloy microstructure on the occurring modes of corrosion and subsequent metal ion release is not well understood. QUESTIONS/PURPOSES: The purpose of this study was to determine whether (1) the microstructure of cast CoCrMo alloy varies broadly between manufacturers and can dictate specific corrosion modes; and whether (2) the microstructure of wrought CoCrMo alloy is more consistent between manufacturers and has low implications on the alloy's corrosion behavior. METHODS: The alloy microstructure of four femoral-stem and three femoral-head designs from four manufacturers was metallographically and electrochemically characterized. Three stem designs were made from cast alloy; all three head designs and one stem design were made from wrought alloy. Alloy samples were sectioned from retrieved components and then polished and etched to visualize grain structure and hard phases such as carbides (eg, M C ) or intermetallic phases (eg, σ phase). Potentiodynamic polarization (PDP) tests were conducted to determine the corrosion potential (E ), corrosion current density (I ), and pitting potential (E ) for each alloy. Four devices were tested within each group, and each measurement was repeated three times to ensure repeatable results. Differences in PDP metrics between manufacturers and between alloys with different hard phase contents were compared using one-way analysis of variance and independent-sample t-tests. Microstructural features such as twin boundaries and slip bands as well as corrosion damage features were viewed and qualitatively assessed in a scanning electron microscope. RESULTS: We found broad variability in implant alloy microstructure for both cast and wrought alloy between manufacturers, but also within the same implant design. In cast alloys, there was no difference in PDP metrics between manufacturers. However, coarse hard phases and clusters of hard phases (mainly intermetallic phases) were associated with severe phase boundary corrosion and pitting corrosion. Furthermore, cast alloys with hard phases had a lower E than those without (0.46 V, SD 0.042; 0.53 V, SD 0.03, respectively; p = 0.015). Wrought alloys exhibited either no hard phases or numerous carbides (M C ). However, the corrosion behavior was mainly affected by lattice defects and banded structures indicative of segregations that appear to be introduced during bar stock manufacturing. Alloys with banding had a lower E (p = 0.008) and higher I (p = 0.028) than alloys without banding (-0.76 V, SD 0.003; -0.73 V, SD 0.009; and 1.14 × 10 mA/cm , SD 1.47 × 10 ; 5.2 × 10 mA/cm , SD 2.57 × 10 , respectively). Alloys with carbides had a slightly higher E (p = 0.046) than those without (-0.755 V, SD 0.005; -0.761 V, SD 0.004); however, alloys with carbides exhibited more severe corrosion damage as a result of phase boundary corrosion, hard phase detachment, and subsequent local crevice corrosion. CONCLUSIONS: The observed variability in CoCrMo alloy microstructure of both cast and wrought components in this study appears to be an important issue to address, perhaps through better standards, to minimize in vivo corrosion. The finding of the banded structures within wrought alloys is especially concerning because it unfavorably influences the corrosion behavior independent of the manufacturer. The findings suggest that a homogeneous alloy microstructure with a minimal hard phase fraction exhibits more favorable corrosion behavior within the in vivo environment of modular taper junctions, thus lowering metal ion release and subsequently the risk of ALTRs to corrosion products. Also, the question arises if hard phases fulfill a useful purpose in metal-on-polyethylene bearings, because they may come with a higher risk of phase boundary corrosion and pitting corrosion and the benefit they provide by adding strength is not needed (unlike in metal-on-metal bearings). CLINICAL RELEVANCE: Implant failure resulting from corrosion processes within modular junctions is a major concern in THA. Our results suggest that implant alloy microstructure is not sufficiently standardized and may also dictate specific corrosion modes and subsequent metal ion release.
[Mh] Termos MeSH primário: Artroplastia de Quadril/instrumentação
Ligas de Cromo/química
Articulação do Quadril/cirurgia
Prótese de Quadril
Polietileno/química
Falha de Prótese
[Mh] Termos MeSH secundário: Artroplastia de Quadril/efeitos adversos
Corrosão
Remoção de Dispositivo
Análise de Falha de Equipamento
Seres Humanos
Desenho de Prótese
Fatores de Risco
Propriedades de Superfície
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Chromium Alloys); 9002-88-4 (Polyethylene)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171118
[Lr] Data última revisão:
171118
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:170909
[St] Status:MEDLINE
[do] DOI:10.1007/s11999-017-5486-3



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