gms | German Medical Science

68. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie
90. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie
45. Tagung des Berufsverbandes der Fachärzte für Orthopädie in Zusammenarbeit mit dem Deutschen Verband für Physiotherapie – Zentralverband der Physiotherapeuten/Krankengymnasten

19. bis 23.10.2004, Berlin

In vivo change of elastic property in polyethylene acetabular components

Meeting Abstract (DGOOC 2004)

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  • presenting/speaker A. Kusaba - Allgemeines KH Ebina, Endoprothetik/Rheumatologie, Ebina/Japan
  • Y. Kuroki - Allgemeines KH Ebina, Endoprothetik/Rheumatologie, Ebina/Japan
  • J. Scholz - Auguste-Viktoria-Krankenhaus, Zentrum für Orthopädie, Schöneberg/Berlin

Deutsche Gesellschaft für Unfallchirurgie. Deutsche Gesellschaft für Orthopädie und orthopädische Chirurgie. Berufsverband der Fachärzte für Orthopädie. 68. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 90. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie und 45. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 19.-23.10.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dguE9-1215

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgu2004/04dgu0270.shtml

Published: October 19, 2004

© 2004 Kusaba et al.
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Outline

Text

Introduction

There have been few detailed reports that referred to the effect of oxidative degradation on the elastic property of the PE cups. We evaluated the elastic property change of the PE cups after the implantation.

Methods

Fifty-six UHMWPE cups retrieved at the revision surgery were evaluated. Thirty-two cups (resin type: GUR412) were sterilized by gamma irradiation and 24 cups (resin type: GUR415) were sterilized by ethylene oxide gas. The years in situ was 7.2 (3.4 to 13.2) in irradiated cups, and 7.7 (2.4 to 14.2) in non-irradiated cups. We measured compression modulus, viscoelasticity, and Vickers hardness of the cups. As a control, six cups aged in shelf in each type were examined.

Results

The compression modulus value in the irradiated cups was 1237 (847-1581) N/mm (control: 976-1513). The value was 1064 (1048-1087) in non-irradiated cups (control: 1042-1050). The viscoelasty (in tangent delta value) was 0.051 (0.038-0.092) (control: 0.040-0.061) in the irradiated cups and was 0.060 (0.050-0.068) (control: 0.60-0.072) in the non-irradiated cups. The Vickers hardness value was 7.38 (6.57-10.30) (control: 6.71-7.95) and was 6.35 (6.28-6.50)(control: 6.29-6.31) in the non-irradiated cups.

Conclusions

Biphasic change was observed in both compression modulus and viscoelasticity in the irradiated cups. From SEM study, the biphasic change seems to come from the configuration change in the articulation surface, such as cracks and delamination on the articulation surface, after that the PE stiffened resulting from the oxidation.