Hip implants -- metal wear impairs bone-forming cells' function

http://www.eurekalert.org/pub_releases/2016-06/c-ub-hi-062216.php

Public Release: 22-Jun-2016
Hip implants -- metal wear impairs bone-forming cells' function
Release of metal ions from metal-on-metal pairings
Charité - Universitätsmedizin Berlin

In metal-on-metal pairings, both the shell and head of an implant consist of a cobalt-chromium-molybdenum alloy. The release of metal ions into the body has been reported as a result of implant wear. Bone loss (osteolysis) was observed in many cases. Some implant manufacturers have withdrawn devices of this type from the market. Recently, physicians and researchers from Charité - Universitätsmedizin Berlin and DRK Klinikum Westend have been able to show that cobalt and chromium release contributes to bone loss. Their findings, which show that metal ions impair the progenitors of bone-forming cells, have been published in the current edition of the journal Biomaterials*.

Total hip replacement has been hailed as the 'operation of the century', and approximately 220,000 such procedures are performed in Germany every year. Most hip replacement operations produce satisfactory results, allowing patients to regain their mobility and pain-free status. Most of the procedures performed today use metal-on-polyethylene or ceramic-on-ceramic implants. Metal-on-metal pairings have been shown to be associated with additional bone loss, leading to premature revision surgery.

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The researchers conclude the findings of their study as follows: the risks associated with metal-on-metal pairings clearly exceed their benefits. The researchers' long-term aim is to optimize patient safety by using their findings to improve the design and composition of future implants.