Untersuchungen an Oberfl�chen und Neogelenkkapseln getragener McKee-Farrar-Endoprothesen

Täger, K. H.

doi:10.1007/bf00415308

Cited by 11 publications

(2 citation statements)

References 14 publications

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“…Briefly, the collection consists of 42 retrieved McKee‐Farrar prostheses from five manufacturers worn by 14 male and 28 female patients. All prostheses were implanted and retrieved by a single surgeon 21. The average patient age at implantation was 61 (range: 38–82) years, and the prostheses lasted for 13.6 (range: 1.3–22) years.…”

Section: Methodsmentioning

confidence: 99%

Wear mechanisms in metal-on-metal bearings: The importance of tribochemical reaction layers

et al. 2009

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Metal-on-metal (MoM) bearings are at the forefront in hip resurfacing arthroplasty. Because of their good wear characteristics and design flexibility, MoM bearings are gaining wider acceptance with market share reaching nearly 10% worldwide. However, concerns remain regarding potential detrimental effects of metal particulates and ion release. Growing evidence is emerging that the local cell response is related to the amount of debris generated by these bearing couples. Thus, an urgent clinical need exists to delineate the mechanisms of debris generation to further reduce wear and its adverse effects. In this study, we investigated the microstructural and chemical composition of the tribochemical reaction layers forming at the contacting surfaces of metallic bearings during sliding motion. Using X-ray photoelectron spectroscopy and transmission electron microscopy with coupled energy dispersive X-ray and electron energy loss spectroscopy, we found that the tribolayers are nanocrystalline in structure, and that they incorporate organic material stemming from the synovial fluid. This process, which has been termed ''mechanical mixing,'' changes the bearing surface of the uppermost 50 to 200 nm from pure metallic to an organic composite material. It hinders direct metal contact (thus preventing adhesion) and limits wear. This novel finding of a mechanically mixed zone of nanocrystalline metal and organic constituents provides the basis for understanding particle release and may help in identifying new strategies to reduce MoM wear. ß

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Section: Methodsmentioning

confidence: 99%

Wear mechanisms in metal-on-metal bearings: The importance of tribochemical reaction layers

et al. 2009

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“…In contrast to the prostheses alloy dissemination of cobalt and chrome, the concentration of chrome was higher than that of cobalt in the capsular tissue ( Tager 1976 ). A reason for the relatively high concentration of chrome in the capsular tissue may be found in the relatively long half-life (of disappearance from soft tissue) of chrome, which is 600 days, in contrast to the half-life of cobalt, which is only 9 days.…”

Section: Discussionmentioning

confidence: 95%

Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints

et al. 2009

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Background and purpose Particles originating from the articulating surfaces of hip endoprostheses often induce an inflammatory response, which can be related to implant failure. We therefore analyzed the metal content in capsular tissue from 44 McKee-Farrar metal-on-metal hip prostheses (with 3 different head sizes) and we also analyzed the morphological structure of layers located on articulating surfaces.Methods Atomic absorption spectrometry (AAS) was used to analyze the metal content in capsular tissue. Visually detectable carbon layers located on the articulating surfaces were evaluated using scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS).Results Metallic debris was detected in all capsular tissue samples but no statistically significant differences in metal content were found in relation to implant head size. The morphological characteristics of the different layer zones allowed an exact analysis of contact and non-contact areas. Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface.Interpretation The implant head size does not appear to influence the amount of metallic debris. The layers obviously act like a lubricating agent because the protection function does not occur in regions without layers where the metal surface often shows numerous scratches. As layers are not generated immediately after the implantation of hip prostheses, these findings may at least partially explain the high amount of wear early after implantation.

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Pattenden¹,

Cadogan²,

Ley³

1997

Dictionary of Organic Compounds

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Untersuchungen an Oberfl�chen und Neogelenkkapseln getragener McKee-Farrar-Endoprothesen

Cited by 11 publications

References 14 publications

Wear mechanisms in metal-on-metal bearings: The importance of tribochemical reaction layers

Wear mechanisms in metal-on-metal bearings: The importance of tribochemical reaction layers

Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints

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