About a decade ago, when metal-on-metal artificial hips began being used, there was concern about their potential to produce high levels of metallic ions, thus causing what were thought to be allergic reactions in patients. In the last two years, further research has raised concerns that the metal debris can ignite severe inflammatory reactions that can destroy or damage tendons, muscles and other soft tissue. For example, in 2008, researchers at Oxford University found that at least seventeen women, all of whom had undergone hip resurfacing with all-metal devices from a variety of manufacturers, experienced abnormal soft-tissue masses in their hip joints. Based on these findings, the researchers deduced that in five years after the surgery, one percent of resurfacing patients could experience damage to soft tissue.
Another research study showed 3.4% of patients who received a metal implant or resurfacing system manufactured by DePuy Orthopaedics experienced adverse reactions. DePuy argues, however, that their internal research and broader studies showed metal sensitivity from its devices were much lower. A study performed at the University of British Columbia also found varying levels of metallic ions in the bloodstreams of patients who received Durom, a model of implant made by Zimmer Holdings, depending on how the device was used. Durom is advertised as a set of ball-and-socket components for use in hip resurfacing, or as a metal socket for use with other components in a conventional hip replacement. The researchers found that patients receiving a regular implant with a Durom socket had significantly higher median blood serum levels of chromium and cobalt, 2.6 times for chromium and 10 times higher for cobalt, than patients who underwent resurfacing with the Durom system. Researchers thus argued that Durom components should no longer be used in standard implants.
Due to this new research, doctors may begin exercising caution in the use of resurfacing in patients other than men aged fifty-five or younger, may begin testing resurfacing patients to determine whether they have high levels of metallic ions in their bloodstreams and may start using diagnostic scans to detect the possibility of soft tissue damage.