Patients implanted with metal-on-metal (MoM) hip implants, especially the recalled DePuy hip replacement, are strongly encouraged to monitor metal ion levels in their blood. Excessive levels of metal ions in the blood stream indicate hip device failure, which may necessitate an additional surgery to replace the MoM implant. While the effects of excessive metal ion levels in the body are not yet wholly understood, damage to muscle, tissue and bone around the MoM implant has been observed and, in some cases, systemic damage to other organs have been observed.
High Metal Ion Blood Levels Signal Device Failure
Until recently, MoM hip implants accounted for about a third of hip devices implanted annually in the U.S., touted as more durable and stable than competing devices. However, research has shown that these devices are prone to early failure, as the metal components rub against each other, releasing metal ions into the blood stream. In the case of the DePuy hip replacement, the failure mechanism consists of the ball riding out towards the edge of the cup (called “edge loading”), shedding cobalt and chromium particles. Levels of metal ions in a recipient’s blood can generally serve as a proxy for metal wear and the failure of a MoM device.
Health Risks Associated with High Metal Ion Blood Levels
When excessive metal debris is generated by a MoM hip device, it first affects the tissue and bone surrounding the artificial hip joint. Doctors removing failed hip implants have noted metallosis in the hip cavity, which can cause inflammation, bone and tissue damage, and the development of pseudotumors. These local symptoms may also contribute to the loosening of a hip device.
Systemic problems have been associated with very high levels of metal ions in the blood, including deafness, blindness, neurological problems, headaches, weakness, and heart problems. While the study of the effects of very high levels of cobalt and chromium on the body is not yet conclusive, initial studies suggest that high levels of metal ions are a cause for alarm.
It is thus critical for recipients of MoM hip replacements to have a doctor regularly test their blood for cobalt and chromium; first, to check the effectiveness of the hip device and second, to prevent damage caused by loose metal particles. Patients can either have blood drawn by a physician or at a laboratory service center. Labs which are qualified to analyze levels of cobalt and chromium in the blood include Quest Diagnostics and LabCorp.
If testing reveals excessive levels of metal ions in the blood, with levels over 5µg/L considered toxic, patients should discuss the possibility of their hip device failing with their orthopedic surgeon. If the patient’s orthopedic surgeon determines that the MoM hip device is failing and/or wearing excessively, the patient should seek legal advice.
Early failure of a hip replacement device is unacceptable and the damage it causes can be irreparable. If you believe you may have a defective metal-on-metal or DePuy hip replacement device, call our offices for a FREE consultation about YOUR legal right to compensation.