Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Aug;26(4):253-258.
doi: 10.1016/j.mporth.2012.05.005.

(v) Simulation and measurement of wear in metal-on-metal bearings in vitro- understanding the reasons for increased wear

John Fisher  1 , Mazen Al Hajjar, Sophie Williams, Joanne Tipper, Eileen Ingham, Louise Jennings
Affiliations

(v) Simulation and measurement of wear in metal-on-metal bearings in vitro- understanding the reasons for increased wear

John Fisher et al. Orthop Trauma. 2012 Aug.

Abstract

A new Stratified Approach For Enhanced Reliability (SAFER) pre-clinical simulation testing of joint prostheses has been described in a preceding paper in this volume. The application of SAFER in vitro simulation and testing to metal-on-metal bearings is described in this review paper. The review aims to provide further understanding of the reasons for, and causes of, increased wear in metal-on-metal hips in a proportion of patients. Variation in positioning (mal-positioning) of the head and cup in hip prostheses results in the head contacting the rim of the cup and producing increased wear. Variation in both translational and rotational positioning has been investigated. Variation in translational positioning of the centres of the head and cup, which is not detected on radiographs, is a frequent occurrence clinically and can result in a substantial increase in wear rate. The variation in translational positioning acts synergistically with variation in rotational positioning to produce substantial increases in wear. These recent findings are consistent with the wear mechanisms and formation of stripe wear reported for ceramic-on-ceramic bearings over a decade ago, and provide insight into the reasons for the variation and increases in the wear rate found clinically in metal-on-metal hips in specific patients, which may cause premature failure.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Diagram of correctly positioned hip prosthesis, with contact patch on head within the bearing area of the cup.
Figure 2
Figure 2
Diagram of rotational mal-position with the cup inclined at 60° and the contact patch on the head intersecting the rim of the cup.
Figure 3
Figure 3
Diagram of translational mal-position with the cup medialized by 0.5 mm from the centre of the head, resulting in the contact patch of the head intersecting the rim of the cup.
Figure 4
Figure 4
Three dimensional co-ordinate measurement of the 36 mm femoral head after translational mal-position showing high stripe wear on the head, where it has contacted the rim of the cup.
See this image and copyright information in PMC

References

    1. Clarke M.T., Darrah C., Stewart T., Ingham E., Fisher J., Nolan J.F. Long-term clinical, radiological and histopathological follow-up of a well-fixed McKee-Farrar metal-on-metal total hip arthroplasty. J Arthroplasty. 2005;20:542–546. - PubMed
    1. Ingham E., Fisher J. Biological reactions to wear debris in total joint replacement. Proceedings of the Institution of Mechanical Engineers. J Eng Med. 2000;214H:21–37. - PubMed
    1. Germain M.A., Hatton A., Williams S. Comparison of the cytotoxicity of clinically relevant cobalt-chromium and alumina ceramic wear particles in vitro. Biomaterials. 2003;24:469–479. - PubMed
    1. Brodner W., Grubl A., Jankovsky R., Meisinger V., Lehr S., Gottsauner Wolf F. Cup inclination angle and serum concentration of cobalt and chromium after metal on metal total hip arthroplasty. J Arthroplasty. 2004;19:66–70. - PubMed
    1. De Haan R., Campbell P.A., Su E.P., De Smet K.A. Revision of metal-on-metal resurfacing arthroplasty of the hip: the influence of malpositioning of components. J Bone Joint Surg Br. 2008;90B:1158–1163. - PubMed