Metal-on-Metal Hip Implants – Risk Assessment for Systemic Health Effects

Several lawsuits claiming adverse health effects from metal-on-metal hip implants have been filed across the United States. To improve our understanding of the effects of hip implants on patients needing the procedure, we conducted studies and risk assessments.

Our ChemRisk team developed a biokinetic model for cobalt, one of the constituents released from the alloy used to manufacture these implants—and defined a reference dose and corresponding blood levels that were considered safe. We then confirmed our findings by conducting 14-, 30-, and 90-day cobalt dosing studies in humans. In addition, we conducted similar risk assessments involving health effects from chromium(III), another metal released from the hip implant alloy, as well as genotoxic and carcinogenic effects from the implantation of these devices. We performed an advanced toxicology and risk assessment for nanoparticles released from implants.

The health sciences community has used our findings to better understand and characterize threshold health effects associated with metal released from metal-on-metal hip implants.