The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Allan Avram Edidin - One of the best experts on this subject based on the ideXlab platform.
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deconvolution of Surface topology for quantification of initial wear in highly cross linked acetabular components for tha
Journal of Biomedical Materials Research, 2002Co-Authors: S M Kurtz, Joseph Turner, M P Herr, Allan Avram EdidinAbstract:Evaluation of the Surface morphology of short-term retrieved cross-linked acetabular components requires differentiation between the features generated during machining and the smaller-scale morphologies generated during the in vivo wear process. Previously, the distinction between the waviness of machining and the roughness of wear has been related to the grain size of the UHMWPE. Here a low-frequency cutoff is proposed, based on the maximum spectral frequency of machining marks, rather than on the grain size of the bulk UHMWPE material, as a reliable method for deconvolving machining marks from in vivo wear following short-term implantation. To this end, as-machined Articulating Surfaces of conventional (GUR 1050) and two groups of highly cross-linked UHMWPE acetabular components were examined to determine whether they exhibited a periodic Surface morphology with a well-defined spatial frequency. The Surface frequency spectra revealed low-frequency peaks associated with the machining marks, which were unique to each type of implant. Furthermore, the Surface frequency spectra appeared uniform within a single group of implants. Statistically significant differences in the Surface roughness and waviness were observed between the three groups of new implants. Our research suggests that machining marks can be effectively deconvolved from the Articulating Surface with the use of a Fourier transform algorithm with a single cutoff frequency of 0.08 1/μm, corresponding to a wavelength of 12.5 μm. The results of this study provide a unified conceptual framework for discriminating between waviness and roughness of the Articulating Surface for machined orthopedic components. The distinction between waviness and roughness is expected to be crucial for the comprehensive evaluation of wear Surfaces after short-term implantation, when machining marks may be partially worn away or plastically deformed in vivo. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 492–500, 2002
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The relationship between the clinical performance and large deformation mechanical behavior of retrieved UHMWPE tibial inserts.
Biomaterials, 2000Co-Authors: S M Kurtz, Clare M. Rimnac, Leslie A Pruitt, C W Jewett, Victor M Goldberg, Allan Avram EdidinAbstract:Abstract Many aspects of the proposed relationship between material properties and clinical performance of UHMWPE components remain unclear. In this study, we explored the hypothesis that the clinical performance of tibial inserts is directly related to its large-deformation mechanical behavior measured near the Articulating Surface. Retrieval analysis was performed on three conventional UHMWPE and three Hylamer™-M tibial components of the same design and manufacturer. Samples of material were then obtained from the worn regions of each implant and subjected to mechanical characterization using the small punch test. Statistically significant relationships were observed between the metrics of the small punch test and the total damage score and the burnishing damage score of the implants. We also examined the near-Surface morphology of the retrievals using transmission electron microscopy. TEM analysis revealed lamellar alignment at and below the wear Surfaces of the conventional UHMWPE retrievals up to a maximum depth of approximately 8 μm, consistent with large-deformation crystalline plasticity. The depth of the plasticity-induced damage layer varied not only between the retrievals, but also between the conventional UHMWPE and Hylamer™-M components. Thus, the results of this study support the hypothesis that the clinical performance of UHMWPE tibial inserts is related to the large-deformation mechanical behavior measured near the Articulating Surface.
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plasticity induced damage layer is a precursor to wear in radiation cross linked uhmwpe acetabular components for total hip replacement
Journal of Arthroplasty, 1999Co-Authors: Allan Avram Edidin, C W Jewett, Lisa A Pruitt, Deborah J Crane, Daniel Roberts, Steven M. KurtzAbstract:Abstract The mechanism for the improved wear resistance of cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) remains unclear. This study investigated the effect of cross-linking achieved by gamma irradiation in nitrogen on the tribologic, mechanical, and morphologic properties of UHMWPE. The goal of this study was to relate UHMWPE properties to the wear mechanism in acetabular-bearing inserts. Wear simulation of acetabular liners was followed by detailed characterization of the mechanical behavior and crystalline morphology at the Articulating Surface. The wear rate was determined to be directly related to the ductility, toughness, and strain-hardening behavior of the UHMWPE. The concept of a plaasticity-induced damage layer is introduced to explain the near-Surface orientation of the crystalline lamellae observed in the wear-tested acetabular liners. Cross-linking reduces abrasive wear of acetabular components by substantially reducing—but not eliminating—the plasticity-induced damage layer that precedes abrasive wear.
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a miniature specimen mechanical testing technique scaled to Articulating Surface of polyethylene components for total joint arthroplasty
Journal of Biomedical Materials Research, 1999Co-Authors: S M Kurtz, C W Jewett, Jude R Foulds, Allan Avram EdidinAbstract:The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (<14 mg) measuring 0.5 mm in thickness and 6.4 mm in diameter. The objective of this study was to demonstrate the feasibility and reproducibility of the small punch test when applied to clinically relevant polyethylenes. Mechanical behavior was characterized during 66 tests performed on GUR4150HP and GUR4120 specimens following alternate sterilization methods and 4 weeks of accelerated aging at 80°C. The small punch test was found to be highly reproducible with regard to characterizing the ductility, ultimate strength, and fracture resistance of sterilized and aged polyethylene. In the future, the small punch test can be used to directly measure mechanical properties near the Articulating Surface of retrieved components. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 48: 75–81, 1999
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A miniature specimen mechanical testing technique scaled to Articulating Surface of polyethylene components for total joint arthroplasty.
Journal of biomedical materials research, 1999Co-Authors: S M Kurtz, C W Jewett, Jude R Foulds, Allan Avram EdidinAbstract:The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (
Clare M. Rimnac - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Retrieved Ultra–High-Molecular-Weight Polyethylene Tibial Components From Rotating-Platform Total Knee Arthroplasty
Journal of Arthroplasty, 2008Co-Authors: Ryan M. Garcia, Matthew J. Kraay, Patrick J. Messerschmitt, Victor M Goldberg, Clare M. RimnacAbstract:Abstract Mobile-bearing total knee Arthroplasties (TKAs) were designed to increase conformity, decrease contact stresses, and decrease polyethylene damage. Our objective was to evaluate the performance of retrieved mobile-bearing TKAs with respect to wear damage of the polyethylene in a series of components obtained at revision surgery. Tibial component polyethylene superior and inferior Surface damage and radiographic radiolucency analysis was conducted on 40 retrieved mobile-bearing TKAs. Higher levels of superior Articulating Surface damage were found to be associated with higher levels of inferior Surface damage in this retrieval study. Greater levels of damage were present on both Surfaces in components with greater radiographic radiolucency scores and mechanically loose components. The mobile-bearing TKA remains vulnerable to polyethylene wear damage at the superior Surface and introduces an independent inferior Surface also vulnerable to wear damage.
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The relationship between the clinical performance and large deformation mechanical behavior of retrieved UHMWPE tibial inserts.
Biomaterials, 2000Co-Authors: S M Kurtz, Clare M. Rimnac, Leslie A Pruitt, C W Jewett, Victor M Goldberg, Allan Avram EdidinAbstract:Abstract Many aspects of the proposed relationship between material properties and clinical performance of UHMWPE components remain unclear. In this study, we explored the hypothesis that the clinical performance of tibial inserts is directly related to its large-deformation mechanical behavior measured near the Articulating Surface. Retrieval analysis was performed on three conventional UHMWPE and three Hylamer™-M tibial components of the same design and manufacturer. Samples of material were then obtained from the worn regions of each implant and subjected to mechanical characterization using the small punch test. Statistically significant relationships were observed between the metrics of the small punch test and the total damage score and the burnishing damage score of the implants. We also examined the near-Surface morphology of the retrievals using transmission electron microscopy. TEM analysis revealed lamellar alignment at and below the wear Surfaces of the conventional UHMWPE retrievals up to a maximum depth of approximately 8 μm, consistent with large-deformation crystalline plasticity. The depth of the plasticity-induced damage layer varied not only between the retrievals, but also between the conventional UHMWPE and Hylamer™-M components. Thus, the results of this study support the hypothesis that the clinical performance of UHMWPE tibial inserts is related to the large-deformation mechanical behavior measured near the Articulating Surface.
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Wear of polyethylene in total joint replacements. Observations from retrieved PCA knee implants.
Clinical orthopaedics and related research, 1992Co-Authors: Timothy M. Wright, Clare M. Rimnac, S. D. Stulberg, L. Mintz, A. K. Tsao, R. W. Klein, C. MccraeAbstract:Observations of wear damage were performed on 12 retrieved porous coated anatomic (PCA) tibial components, all of which were removed because of excessive polyethylene wear. Density measurements of the remaining polyethylene were obtained as a function of depth from the Surface of the components. Comparison to previous results from similar studies of total condylar type knee components and total hip acetabular components revealed distinct differences between the types and severity of damage, emphasizing the influence of design factors on the corresponding wear damage. These results confirm previous conclusions that nonconforming Articulating Surfaces on thin polyethylene components will be at higher risk of damage than more conforming Surfaces on thicker components. It also appears that the high cyclic loads to which polyethylene implants are subjected in vivo are most responsible for the degradation in properties of the material near the Articulating Surface, although the heat pressing of the Articulating Surface of the PCA components may contribute to the problem.
S M Kurtz - One of the best experts on this subject based on the ideXlab platform.
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deconvolution of Surface topology for quantification of initial wear in highly cross linked acetabular components for tha
Journal of Biomedical Materials Research, 2002Co-Authors: S M Kurtz, Joseph Turner, M P Herr, Allan Avram EdidinAbstract:Evaluation of the Surface morphology of short-term retrieved cross-linked acetabular components requires differentiation between the features generated during machining and the smaller-scale morphologies generated during the in vivo wear process. Previously, the distinction between the waviness of machining and the roughness of wear has been related to the grain size of the UHMWPE. Here a low-frequency cutoff is proposed, based on the maximum spectral frequency of machining marks, rather than on the grain size of the bulk UHMWPE material, as a reliable method for deconvolving machining marks from in vivo wear following short-term implantation. To this end, as-machined Articulating Surfaces of conventional (GUR 1050) and two groups of highly cross-linked UHMWPE acetabular components were examined to determine whether they exhibited a periodic Surface morphology with a well-defined spatial frequency. The Surface frequency spectra revealed low-frequency peaks associated with the machining marks, which were unique to each type of implant. Furthermore, the Surface frequency spectra appeared uniform within a single group of implants. Statistically significant differences in the Surface roughness and waviness were observed between the three groups of new implants. Our research suggests that machining marks can be effectively deconvolved from the Articulating Surface with the use of a Fourier transform algorithm with a single cutoff frequency of 0.08 1/μm, corresponding to a wavelength of 12.5 μm. The results of this study provide a unified conceptual framework for discriminating between waviness and roughness of the Articulating Surface for machined orthopedic components. The distinction between waviness and roughness is expected to be crucial for the comprehensive evaluation of wear Surfaces after short-term implantation, when machining marks may be partially worn away or plastically deformed in vivo. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 492–500, 2002
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The relationship between the clinical performance and large deformation mechanical behavior of retrieved UHMWPE tibial inserts.
Biomaterials, 2000Co-Authors: S M Kurtz, Clare M. Rimnac, Leslie A Pruitt, C W Jewett, Victor M Goldberg, Allan Avram EdidinAbstract:Abstract Many aspects of the proposed relationship between material properties and clinical performance of UHMWPE components remain unclear. In this study, we explored the hypothesis that the clinical performance of tibial inserts is directly related to its large-deformation mechanical behavior measured near the Articulating Surface. Retrieval analysis was performed on three conventional UHMWPE and three Hylamer™-M tibial components of the same design and manufacturer. Samples of material were then obtained from the worn regions of each implant and subjected to mechanical characterization using the small punch test. Statistically significant relationships were observed between the metrics of the small punch test and the total damage score and the burnishing damage score of the implants. We also examined the near-Surface morphology of the retrievals using transmission electron microscopy. TEM analysis revealed lamellar alignment at and below the wear Surfaces of the conventional UHMWPE retrievals up to a maximum depth of approximately 8 μm, consistent with large-deformation crystalline plasticity. The depth of the plasticity-induced damage layer varied not only between the retrievals, but also between the conventional UHMWPE and Hylamer™-M components. Thus, the results of this study support the hypothesis that the clinical performance of UHMWPE tibial inserts is related to the large-deformation mechanical behavior measured near the Articulating Surface.
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a miniature specimen mechanical testing technique scaled to Articulating Surface of polyethylene components for total joint arthroplasty
Journal of Biomedical Materials Research, 1999Co-Authors: S M Kurtz, C W Jewett, Jude R Foulds, Allan Avram EdidinAbstract:The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (<14 mg) measuring 0.5 mm in thickness and 6.4 mm in diameter. The objective of this study was to demonstrate the feasibility and reproducibility of the small punch test when applied to clinically relevant polyethylenes. Mechanical behavior was characterized during 66 tests performed on GUR4150HP and GUR4120 specimens following alternate sterilization methods and 4 weeks of accelerated aging at 80°C. The small punch test was found to be highly reproducible with regard to characterizing the ductility, ultimate strength, and fracture resistance of sterilized and aged polyethylene. In the future, the small punch test can be used to directly measure mechanical properties near the Articulating Surface of retrieved components. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 48: 75–81, 1999
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A miniature specimen mechanical testing technique scaled to Articulating Surface of polyethylene components for total joint arthroplasty.
Journal of biomedical materials research, 1999Co-Authors: S M Kurtz, C W Jewett, Jude R Foulds, Allan Avram EdidinAbstract:The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (
C W Jewett - One of the best experts on this subject based on the ideXlab platform.
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The relationship between the clinical performance and large deformation mechanical behavior of retrieved UHMWPE tibial inserts.
Biomaterials, 2000Co-Authors: S M Kurtz, Clare M. Rimnac, Leslie A Pruitt, C W Jewett, Victor M Goldberg, Allan Avram EdidinAbstract:Abstract Many aspects of the proposed relationship between material properties and clinical performance of UHMWPE components remain unclear. In this study, we explored the hypothesis that the clinical performance of tibial inserts is directly related to its large-deformation mechanical behavior measured near the Articulating Surface. Retrieval analysis was performed on three conventional UHMWPE and three Hylamer™-M tibial components of the same design and manufacturer. Samples of material were then obtained from the worn regions of each implant and subjected to mechanical characterization using the small punch test. Statistically significant relationships were observed between the metrics of the small punch test and the total damage score and the burnishing damage score of the implants. We also examined the near-Surface morphology of the retrievals using transmission electron microscopy. TEM analysis revealed lamellar alignment at and below the wear Surfaces of the conventional UHMWPE retrievals up to a maximum depth of approximately 8 μm, consistent with large-deformation crystalline plasticity. The depth of the plasticity-induced damage layer varied not only between the retrievals, but also between the conventional UHMWPE and Hylamer™-M components. Thus, the results of this study support the hypothesis that the clinical performance of UHMWPE tibial inserts is related to the large-deformation mechanical behavior measured near the Articulating Surface.
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plasticity induced damage layer is a precursor to wear in radiation cross linked uhmwpe acetabular components for total hip replacement
Journal of Arthroplasty, 1999Co-Authors: Allan Avram Edidin, C W Jewett, Lisa A Pruitt, Deborah J Crane, Daniel Roberts, Steven M. KurtzAbstract:Abstract The mechanism for the improved wear resistance of cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) remains unclear. This study investigated the effect of cross-linking achieved by gamma irradiation in nitrogen on the tribologic, mechanical, and morphologic properties of UHMWPE. The goal of this study was to relate UHMWPE properties to the wear mechanism in acetabular-bearing inserts. Wear simulation of acetabular liners was followed by detailed characterization of the mechanical behavior and crystalline morphology at the Articulating Surface. The wear rate was determined to be directly related to the ductility, toughness, and strain-hardening behavior of the UHMWPE. The concept of a plaasticity-induced damage layer is introduced to explain the near-Surface orientation of the crystalline lamellae observed in the wear-tested acetabular liners. Cross-linking reduces abrasive wear of acetabular components by substantially reducing—but not eliminating—the plasticity-induced damage layer that precedes abrasive wear.
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a miniature specimen mechanical testing technique scaled to Articulating Surface of polyethylene components for total joint arthroplasty
Journal of Biomedical Materials Research, 1999Co-Authors: S M Kurtz, C W Jewett, Jude R Foulds, Allan Avram EdidinAbstract:The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (<14 mg) measuring 0.5 mm in thickness and 6.4 mm in diameter. The objective of this study was to demonstrate the feasibility and reproducibility of the small punch test when applied to clinically relevant polyethylenes. Mechanical behavior was characterized during 66 tests performed on GUR4150HP and GUR4120 specimens following alternate sterilization methods and 4 weeks of accelerated aging at 80°C. The small punch test was found to be highly reproducible with regard to characterizing the ductility, ultimate strength, and fracture resistance of sterilized and aged polyethylene. In the future, the small punch test can be used to directly measure mechanical properties near the Articulating Surface of retrieved components. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 48: 75–81, 1999
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A miniature specimen mechanical testing technique scaled to Articulating Surface of polyethylene components for total joint arthroplasty.
Journal of biomedical materials research, 1999Co-Authors: S M Kurtz, C W Jewett, Jude R Foulds, Allan Avram EdidinAbstract:The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (
Steven M. Kurtz - One of the best experts on this subject based on the ideXlab platform.
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plasticity induced damage layer is a precursor to wear in radiation cross linked uhmwpe acetabular components for total hip replacement
Journal of Arthroplasty, 1999Co-Authors: Allan Avram Edidin, C W Jewett, Lisa A Pruitt, Deborah J Crane, Daniel Roberts, Steven M. KurtzAbstract:Abstract The mechanism for the improved wear resistance of cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) remains unclear. This study investigated the effect of cross-linking achieved by gamma irradiation in nitrogen on the tribologic, mechanical, and morphologic properties of UHMWPE. The goal of this study was to relate UHMWPE properties to the wear mechanism in acetabular-bearing inserts. Wear simulation of acetabular liners was followed by detailed characterization of the mechanical behavior and crystalline morphology at the Articulating Surface. The wear rate was determined to be directly related to the ductility, toughness, and strain-hardening behavior of the UHMWPE. The concept of a plaasticity-induced damage layer is introduced to explain the near-Surface orientation of the crystalline lamellae observed in the wear-tested acetabular liners. Cross-linking reduces abrasive wear of acetabular components by substantially reducing—but not eliminating—the plasticity-induced damage layer that precedes abrasive wear.
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Simulation of initial frontside and backside wear rates in a modular acetabular component with multiple screw holes
Journal of biomechanics, 1999Co-Authors: Steven M. Kurtz, Jorge A. Ochoa, Chad B. Hovey, Christopher WhiteAbstract:Abstract A sliding distance-based finite element formulation was implemented to predict initial wear rates at the front and back Surfaces of a commercially available modular polyethylene component during in vitro loading conditions. We found that contact area, contact stress, and wear at the back Surface were more sensitive to the liner/shell conformity than the presence of multiple screw holes. Furthermore, backside linear and volumetric wear rates were at least three orders of magnitude less than respective wear estimates at the Articulating Surface. This discrepancy was primarily attributed to the difference in maximum sliding distances at the Articulating Surfaces (measured in mm) versus the back Surface (measured in μm). This is the first study in which backside wear has been quantified and explicitly compared with frontside wear using clinically relevant metrics established for the Articulating Surface. The results of this study suggest that with a polished metal shell, the presence of screw holes does not substantially increase abrasive backside wear when compared with the effects of backside nonconformity.
