The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Eduardo A. Salvati - One of the best experts on this subject based on the ideXlab platform.
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A New Radiographic Sign in Total Hip Arthroplasty
2003Co-Authors: Peter W. Callander, Eduardo A. SalvatiAbstract:The production of Metallic Debris from the wear of nonbearing surfaces of a total hip arthroplasty is encountered frequently. We describe a case of extreme generation of Metallic Debris that resulted in the radiographic outlining of the joint cavity. A 71-year-old woman with a total hip arthroplasty experienced dislodgment of the polyethylene liner from its acetabular shell, resulting in metal-on-metal articulation of the femoral head and the cup. This articulation created severe metallosis that could be seen on preoperative radiographs, producing the described bubble sign. At the time of revision surgery, copious Metallic Debris was seen macroscopically. This newly described radiographic sign should alert the arthroplasty surgeon to the extent of Metallic wear. Key words: Metallic Debris, metallosis, total hip arthroplasty (THA), modularity. Copyright 2003, Elsevier Science (USA). All rights reserved.
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The bubble sign: a new radiographic sign in total hip arthroplasty.
The Journal of arthroplasty, 2003Co-Authors: Peter W. Callander, Eduardo A. SalvatiAbstract:The production of Metallic Debris from the wear of nonbearing surfaces of a total hip arthroplasty is encountered frequently. We describe a case of extreme generation of Metallic Debris that resulted in the radiographic outlining of the joint cavity. A 71-year-old woman with a total hip arthroplasty experienced dislodgment of the polyethylene liner from its acetabular shell, resulting in metal-on-metal articulation of the femoral head and the cup. This articulation created severe metallosis that could be seen on preoperative radiographs, producing the described bubble sign. At the time of revision surgery, copious Metallic Debris was seen macroscopically. This newly described radiographic sign should alert the arthroplasty surgeon to the extent of Metallic wear.
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Particulate Metallic Debris in cemented total hip arthroplasty.
Clinical orthopaedics and related research, 1993Co-Authors: Eduardo A. Salvati, F. Betts, Stephen B. DotyAbstract:Several studies conducted by the authors in the last six years demonstrate that the generation of Metallic Debris is more severe with titanium alloy than with cobalt-chrome alloy femoral components in cemented total hip arthroplasty (THA). The Debris is generated from the articulating surface, particularly if entrapped acrylic Debris produces three-body wear, and from the stem surface when the component loosens and abrades against fragmented cement. In selected cases in which the titanium Metallic Debris is copious, premature failure and severe progressive bone loss occurs. Electron microscopy demonstrates that the particles of Metallic Debris can be extremely small (a few hundredths of 1 micron). They are phagocytized by the macrophages and transported to the phagolysosomes. In this highly corrosive environment, the very high surface area of the particles may release toxic concentrations of the constituents of the alloy intracellularly, probably leading to progressive cell degeneration and death, with subsequent release of intracellular enzymes and ingested Metallic Debris. This cycle most likely repeats itself, leading to tissue necrosis. The results presented do not support the use of titanium alloy femoral components for cemented THA, particularly for the articulating surface.
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Metallic Debris in femoral endosteolysis in failed cemented total hip arthroplasties.
Clinical orthopaedics and related research, 1992Co-Authors: Michael H. Huo, Eduardo A. Salvati, F. Betts, Jay R. Lieberman, Manjula BansalAbstract:A prospective study was undertaken to quantitate Metallic and cement Debris in 12 consecutive patients with femoral endosteolysis (FE) and aseptic loosening of a cemented total hip arthroplasty. The mean interval between primary and revision surgery was 9.6 years. The average time to onset of FE was 8.9 years. There were four stems each of cobalt-chromium (Co-Cr), stainless steel (SS), and titanium alloy. At revision, tissue was retrieved from FE, the femoral bone-cement pseudomembrane, and the joint pseudocapsule. Histology of these tissues was studied using light and polarized microscopy. Metal and barium levels were measured by atomic absorption spectrophotometry. A histiocytic reaction and particulate cement Debris were seen in every case. Polyethylene wear Debris was noted in 11 of 12 cases (92%), and Metallic Debris in four cases (33%). Detectable metal levels were found in the FE in all cases. Metal levels were on average 2.5 times higher in FE than in femoral pseudomembrane, and 4.2 times higher than in joint pseudocapsule. This difference was statistically significant for the Co-Cr and SS groups. Barium levels in areas of FE were on average 1.7 times and 42.4 times higher than in femoral pseudomembrane and joint pseudocapsule, respectively. The difference seen between the FE and the joint pseudocapsule tissue was significant for all three alloy groups. The authors' data demonstrated higher metal and barium levels in FE than in the other tissue sites. Polyethylene and cement Debris were noted in nearly every case. Cement, polyethylene, and Metallic particulate wear Debris may contribute to the pathogenesis and progression of FE.
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Wear Debris in cemented total hip arthroplasty.
Orthopedics, 1991Co-Authors: Michael H. Huo, Eduardo A. Salvati, Robert L. BulyAbstract:One of the most prevalent clinical problems in long-term follow up of total hip arthroplasty patients is loosening of prosthetic fixation. Factors contributing to mechanical failure of total hip reconstruction are complex and multiple. It has become increasingly apparent that wear Debris from the prosthetic components may contribute significantly to this process. The authors summarize some of the current concepts concerning the detrimental effects of Metallic Debris in total hip arthroplasty.
P.h. Shipway - One of the best experts on this subject based on the ideXlab platform.
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Evolution of plasticity-based wear damage in gross sliding fretting of a Ti-6Al-4V non-conforming contact
Tribology International, 2017Co-Authors: A. L. Mohd Tobi, Wei Sun, P.h. ShipwayAbstract:This paper examines the evidence for a plasticity based wear mechanism in the fretting wear of Ti-6Al-4V. Driven by near-surface plastic strain accumulation, the generation of wear Debris evolves from coarse Metallic Debris towards loose fine oxide Debris generating W-shape wear scar. The overall wear effect however, is less pronounced at the later stages of wear due to a reduced propensity for plastic deformation in the contact associated with wear induced contact pressure reduction. The evidence suggests that the high wear rate at the early stages of a fretting test are due to Debris = generation associated with gross plasticity whilst at the later stages, lower wear is associated with less plasticity accumulation.
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Evolution of plasticity-based wear damage in gross sliding fretting of a non-conforming Ti-6Al-4V contact
2016Co-Authors: A. L. Mohd Tobi, Wei Sun, P.h. ShipwayAbstract:This paper examines the evidence for a plasticity based wear mechanism in the fretting wear of Ti-6Al-4V. Driven by near-surface plastic strain accumulation, the generation of wear Debris evolves from coarse Metallic Debris towards loose fine oxide Debris generating W-shape wear scar. The overall wear effect however, is less pronounced at the later stages of wear due to a reduced propensity for plastic deformation in the contact associated with reductions in the contact pressure due to wear in the contact. The evidence suggests that the high wear rate at the early stages of a fretting test are due to Debris generation associated with gross plasticity whilst at the later stages, lower wear is associated with less plasticity accumulation.
William J Maloney - One of the best experts on this subject based on the ideXlab platform.
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Human macrophage response to retrieved titanium alloy particles in vitro.
Clinical orthopaedics and related research, 1996Co-Authors: William J Maloney, Ron James, Robert L. SmithAbstract:Titanium alloy particles were isolated from membranes obtained at revision arthroplasty. Addition of these retrieved particles to human monocytes/macrophages in cell culture resulted in morphologic change and metabolic activation. Cells exposed to these particles actively phagocytized the Metallic Debris, resulting in an increase in cytoplasm and a polarization of ingested metal. The metabolic response of the macrophages included increased release of prostaglandin E2, interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha, and increased hexosaminidase activity. Increased release of interleukin-1 beta was maximal 6 to 12 hours after particle exposure. These data show that retrieved titanium alloy particles activate macrophages in vitro in an analogous fashion to that observed around failed arthroplasties.
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Effects of Metallic Debris on adult bovine articular chondrocyte metabolism in vitro
Journal of Applied Biomaterials, 1994Co-Authors: William J Maloney, David J Schurman, Frank Castro, R. Lane SmithAbstract:The purpose of this study was to examine the effects of particles, derived from metals commonly used in joint prostheses, on chondrocyte proliferation, metabolism, and morphology in vitro. Chondrocyte viability was influenced by the type and concentration of metal particle added. Cobalt was toxic to chondrocytes at all particle concentrations (0.83–0.000083%, v/v), whereas the chromium, titanium and titanium-aluminum particles only effected chondrocyte viability at high concentrations. The metabolic response of chondrocytes to particulate Debris as assessed by caseinase, collagenase, and hexosaminidase activities were variable at low concentrations but were always reduced at high concentrations (0.83% v/v). Prostaglandin E2 levels in the medium showed a steady increase when particle load increased, except in the medium of chondrocytes exposed to titanium-aluminum. Scanning electron microscopy of chondrocytes exposed to titanium showed ruffled cell borders and frequent membrane blebbings. This was in contrast to chondrocytes exposed to cobalt, where the crenated appearance indicated cell death, and titanium-aluminum, where the cells appeared quiescent. These findings show that metal particles alter chondrocyte viability and metabolism and suggest that particulate Debris may influence the integrity and stability of articular cartilage following hemiarthroplasty. © 1994 John Wiley & Sons, Inc.
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fibroblast response to Metallic Debris in vitro enzyme induction cell proliferation and toxicity
Journal of Bone and Joint Surgery American Volume, 1993Co-Authors: William J Maloney, R L Smith, F Castro, David J SchurmanAbstract:Bovine synovial fibroblasts in primary monolayer culture were exposed to particulate Metallic Debris. The effects of the Metallic particles on the synthesis and secretion of proteolytic enzymes and on cell proliferation and viability were examined. Uniform suspensions of titanium, titanium-aluminum, cobalt, and chromium particles, ranging in size from approximately 0.1 to ten micrometers (average, one to three micrometers), were prepared; the particle concentrations (the volume of particles divided by the total volume of the suspension) ranged from 0.0005 to 5 per cent. Aliquots of the particle suspensions were added to the synovial fibroblast cultures. The final particle concentrations in the media ranged from 0.0000083 to 0.83 per cent. After seventy-two hours of exposure, each medium was harvested and was assayed for proteolytic and collagenolytic activity and for hexosaminidase levels. Neutral metalloproteases, quantified by collagenolytic and caseinolytic (proteolytic) activity, represent enzymes, secreted by cells, that are capable of degrading extracellular matrix. Hexosaminidase is a marker for lysosomal enzyme activity that can include more than thirty enzymes, such as proteases, lipases, nucleases, and phosphatases. Cell proliferation was quantified by uptake of 3H-thymidine. Cell morphology was examined by scanning electron microscopy. Titanium, titanium-aluminum, and chromium significantly stimulated 3H-thymidine uptake at low particle concentrations (p < 0.01, p < 0.002, and p < 0.002, respectively). Exposure to cobalt, even at the lowest particle concentration, resulted in a significant decrease in thymidine uptake (p = 0.027). At the highest particle concentrations, all particles were toxic, as evidenced by the absence of thymidine uptake. At high particle concentrations, all of the metals caused a decrease in caseinolytic (proteolytic) and collagenolytic activity in the culture media. Titanium elevated the lysosomal enzyme marker, hexosaminidase, except at high concentrations. Chromium and titanium-aluminum had no significant effect on hexosaminidase at any particle concentration, while cobalt decreased all enzyme markers at mid-particle to high-particle concentrations. Scanning electron microscopy demonstrated that the morphological response of fibroblasts to titanium included membrane-ruffling and extension of filopodia, typical of active fibroblasts. In contrast, exposure to cobalt at the same concentration resulted in cell crenation, indicative of cell death.
A. L. Mohd Tobi - One of the best experts on this subject based on the ideXlab platform.
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Evolution of plasticity-based wear damage in gross sliding fretting of a Ti-6Al-4V non-conforming contact
Tribology International, 2017Co-Authors: A. L. Mohd Tobi, Wei Sun, P.h. ShipwayAbstract:This paper examines the evidence for a plasticity based wear mechanism in the fretting wear of Ti-6Al-4V. Driven by near-surface plastic strain accumulation, the generation of wear Debris evolves from coarse Metallic Debris towards loose fine oxide Debris generating W-shape wear scar. The overall wear effect however, is less pronounced at the later stages of wear due to a reduced propensity for plastic deformation in the contact associated with wear induced contact pressure reduction. The evidence suggests that the high wear rate at the early stages of a fretting test are due to Debris = generation associated with gross plasticity whilst at the later stages, lower wear is associated with less plasticity accumulation.
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Evolution of plasticity-based wear damage in gross sliding fretting of a non-conforming Ti-6Al-4V contact
2016Co-Authors: A. L. Mohd Tobi, Wei Sun, P.h. ShipwayAbstract:This paper examines the evidence for a plasticity based wear mechanism in the fretting wear of Ti-6Al-4V. Driven by near-surface plastic strain accumulation, the generation of wear Debris evolves from coarse Metallic Debris towards loose fine oxide Debris generating W-shape wear scar. The overall wear effect however, is less pronounced at the later stages of wear due to a reduced propensity for plastic deformation in the contact associated with reductions in the contact pressure due to wear in the contact. The evidence suggests that the high wear rate at the early stages of a fretting test are due to Debris generation associated with gross plasticity whilst at the later stages, lower wear is associated with less plasticity accumulation.
Vincent D. Pellegrini - One of the best experts on this subject based on the ideXlab platform.
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Particulate titanium and cobalt-chrome Metallic Debris in failed total knee arthroplasty: A quantitative histologic analysis
The Journal of arthroplasty, 1994Co-Authors: Jackson K. La Budde, John F. Orosz, Thomas A. Bonfiglio, Vincent D. PellegriniAbstract:Histologic examination of synovial tissue from the revisions of six cobalt-chrome and six titanium alloy total knee arthroplasties was made. Aseptic polyethylene wear-through had resulted in metal-on-metal contact of bearing surfaces and was the primary indication for revision surgery in all knees. The cobalt-chrome alloy prostheses failed at the femorotibial articulation at a mean of 92 months, while the titanium prostheses experienced patellofemoral failure at a mean of 39 months after implantation. Neither alloy was associated with any meaningful inflammatory infiltrate, and cement Debris was comparable in both groups. Titanium alloy knees generated significantly more Metallic Debris than the cobalt-chrome alloy knees (P < .001). Cobalt-chrome alloy knees had more polyethylene Debris (P < .01) and a greater number of histiocytes (P < .005). Titanium and polyethylene Debris were associated with a prominent giant cell reaction. Titanium exhibited greater abrasive wear and elicited a different cellular response than cobalt-chrome under conditions of polyethylene failure allowing metal-on-metal contact. The variability of this foreign body reaction may be due to important differences in particle size and number, as well as in the material properties of the two alloys.