Cobalt Chromium Toxicity Resource Center

The correlation between prostheses failure and elevated metal ion levels in patients





This study focuses on whether or not higher metal ions in the blood could help determine the likelihood of prostheses failure in patients with metal on metal (MOM) implants or total hip arthroplasty. The study involved 597 patients who received hip implants approximately one year prior. Patients with failed prostheses and patients with non-failed prostheses were compared via their blood metal ion levels. A prosthetic was considered a failure if they were revised, a revision was pending, or the patient reported poor hip function.

Patients with failed implants had elevated cobalt and chromium blood levels compared to patients with non-failed hips.  Patients with failed hip resurfacing (replacement of the joint’s articular surface) had less blood cobalt levels than patients with failed total hip arthroplasty (surgical removal of the femur’s neck and insertion of a stem deep within the bone connecting with the pelvic socket and liner). There was not a significant difference in blood chromium levels between the two procedures.

The presence and amount of the metal ions were good indicators of whether or not a hip would fail. There was a 23% increase in failure among patients with a total hip arthroplasty for each increase in 1 part per billion (µg/L) of metal ions. Whereas, patients with hip resurfacing had a 5% increase in failure with each increase in 1 part per billion (µg/L ) of metal ions.

In conclusion, there was a direct correlation between higher levels of blood metal ions and metal on metal hip resurfacing and total hip arthroplasty failures.

Source: Surveillance of Patients with Metal-on-metal hip resurfacing and total hip prostheses


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