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

Braunstein V, Sprecher CM, Wimmer MA, Milz S, Taeger G - Acta Orthop (2009)

Bottom Line: Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface.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.

View Article: PubMed Central - PubMed

Affiliation: AO Research Institute, AO Foundation, Davos, Switzerland. volker.braunstein@aofoundation.org

ABSTRACT

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 X-ray 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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A and B. Exemplary XPS result diagrams of two different sputter depths. C. Graphical demonstration of the overall results of XPS analysis: A 3–4-nm thin oxide film was located directly on the prosthesis surface. On top of the oxide film, a second layer with a thickness of up to 3 μm and composed of different elements was detected.
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Figure 0005: A and B. Exemplary XPS result diagrams of two different sputter depths. C. Graphical demonstration of the overall results of XPS analysis: A 3–4-nm thin oxide film was located directly on the prosthesis surface. On top of the oxide film, a second layer with a thickness of up to 3 μm and composed of different elements was detected.

Mentions: XPS analysis was based on several high-resolution depth profiles. Figure 5 (panels A and B) shows two examples for two different sputtering depths. These two examples are not representative of the overall results. The overall results of the XPS analyses are shown in Figure 5C. A 3–4-nm thin oxide film was located directly on the prosthesis surface. On top of that oxide film, a second layer with a thickness of up to 3μm and composed of different elements was detected. The elements detected here were oxygen (55%), carbon (13%), calcium (13%), phosphorus (13%), and nitrogen (6%) (Figure 5C). Regarding the proportions of these components, the analyses showed minor in-depth and major lateral variations. The reason for the lateral variations is clearly related to the XPS spot-diameter of 50 μm, which was larger than the expansion of most layers themselves.


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

Braunstein V, Sprecher CM, Wimmer MA, Milz S, Taeger G - Acta Orthop (2009)

A and B. Exemplary XPS result diagrams of two different sputter depths. C. Graphical demonstration of the overall results of XPS analysis: A 3–4-nm thin oxide film was located directly on the prosthesis surface. On top of the oxide film, a second layer with a thickness of up to 3 μm and composed of different elements was detected.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823209&req=5

Figure 0005: A and B. Exemplary XPS result diagrams of two different sputter depths. C. Graphical demonstration of the overall results of XPS analysis: A 3–4-nm thin oxide film was located directly on the prosthesis surface. On top of the oxide film, a second layer with a thickness of up to 3 μm and composed of different elements was detected.
Mentions: XPS analysis was based on several high-resolution depth profiles. Figure 5 (panels A and B) shows two examples for two different sputtering depths. These two examples are not representative of the overall results. The overall results of the XPS analyses are shown in Figure 5C. A 3–4-nm thin oxide film was located directly on the prosthesis surface. On top of that oxide film, a second layer with a thickness of up to 3μm and composed of different elements was detected. The elements detected here were oxygen (55%), carbon (13%), calcium (13%), phosphorus (13%), and nitrogen (6%) (Figure 5C). Regarding the proportions of these components, the analyses showed minor in-depth and major lateral variations. The reason for the lateral variations is clearly related to the XPS spot-diameter of 50 μm, which was larger than the expansion of most layers themselves.

Bottom Line: Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface.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.

View Article: PubMed Central - PubMed

Affiliation: AO Research Institute, AO Foundation, Davos, Switzerland. volker.braunstein@aofoundation.org

ABSTRACT

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 X-ray 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.

Show MeSH
Related in: MedlinePlus