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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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Related in: MedlinePlus

Explanted McKee-Farrar acetabular component (size 41.5 mm). All explanted prostheses showed layers that were visible to the naked eye. The morphology of the layers was inhomogeneous. Samples were cut into several smaller pieces for further evaluation.
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Figure 0002: Explanted McKee-Farrar acetabular component (size 41.5 mm). All explanted prostheses showed layers that were visible to the naked eye. The morphology of the layers was inhomogeneous. Samples were cut into several smaller pieces for further evaluation.

Mentions: Layers. All explanted prostheses showed layers that were visible to the naked eye (Figure 2). The morphology of the layers was inhomogeneous. Using the SE mode, areas without layers and without damage were found between areas with thin layers. Zones of thick layers were found in regions surrounded by thin layers. The surface conditions of thin layers were rather smooth, while thick zones showed a rough and squamous surface with cracks. The borders of thick areas were sharply defined, while thin layers had rather diffuse borders (Figure 3a). Areas without layers and without damage presented no appearance of layer ablation because the borders of these areas had no sharp-edged or spiky configuration.


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)

Explanted McKee-Farrar acetabular component (size 41.5 mm). All explanted prostheses showed layers that were visible to the naked eye. The morphology of the layers was inhomogeneous. Samples were cut into several smaller pieces for further evaluation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 0002: Explanted McKee-Farrar acetabular component (size 41.5 mm). All explanted prostheses showed layers that were visible to the naked eye. The morphology of the layers was inhomogeneous. Samples were cut into several smaller pieces for further evaluation.
Mentions: Layers. All explanted prostheses showed layers that were visible to the naked eye (Figure 2). The morphology of the layers was inhomogeneous. Using the SE mode, areas without layers and without damage were found between areas with thin layers. Zones of thick layers were found in regions surrounded by thin layers. The surface conditions of thin layers were rather smooth, while thick zones showed a rough and squamous surface with cracks. The borders of thick areas were sharply defined, while thin layers had rather diffuse borders (Figure 3a). Areas without layers and without damage presented no appearance of layer ablation because the borders of these areas had no sharp-edged or spiky configuration.

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