Intergranular corrosion-fatigue failure of cobalt-alloy femoral stems. A failure analysis of two implants

J. L. Gilbert, C. A. Buckley, J. J. Jacobs, K. C. Bertin, M. R. Zernich

Research output: Contribution to journalArticle

148 Scopus citations

Abstract

Two modular hip implants with a cobalt-alloy head and a cobalt-alloy stem were retrieved after a fracture had occurred in the neck region of the femoral component, eighty-five and seventy months after implantation. Both implants failed less than one millimeter distal to the taper junction between the head and the stem (outside of the taper). The fracture surfaces of the implant were investigated with the use of scanning electron microscopy, to determine the nature of the failure process. The fractures occurred at the grain boundaries of the microstructure and appeared to be the result of three factors: porosity at the grain boundaries; intergranular corrosive attack, initiated both at the head-neck taper and at the free surface; and cyclic fatigue-loading of the stem. The corrosive attack of the free surface was initiated, in part, by the egression of surface grains and by the ingression of fluid into the intergranular regions. Sectioned surfaces showed extensive intergranular corrosive attack in the prosthetic neck localized in the region of the head-neck taper junction and penetrating deeply into the microstructure.

Original languageEnglish (US)
Pages (from-to)110-115
Number of pages6
JournalJournal of Bone and Joint Surgery - Series A
Volume76
Issue number1
DOIs
StatePublished - Jan 1 1994

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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