Sphericity Examinations of Arthroplastic Total Hip Prostheses

Ungethüm, M; Jäger, Michael; Witt, A. N.; Hildebrandt, H

doi:10.3109/17453677408989164

Cited by 2 publications

(1 citation statement)

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“…Deviations in shape of prosthesis components are caused by production inaccuracies (Ungethum et al 1974) or by material abrasion (Tager et al 1997), the latter because prosthesis components are not uniformly stressed during normal gait (Ramamurti et al 1996). Thus, contact areas and non-contact areas have to be distinguished.…”

Section: Discussionmentioning

confidence: 99%

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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Section: Discussionmentioning

confidence: 99%