Metal-on-Metal Hip Implants Risks Outweigh Benefits

A group of medical researchers and scientists have determined that the potential risks from metal-on-metal hip implants may outweigh any health benefits provided by these devices.

This is because of higher revision rates are linked to the newer hip replacement designs and the mounting and growing concerns about metal ion blood poisoning, known as metallosis.

The California Technology Assessment Forum (CTAF) has released an assessment of the benefits and effectiveness of using metal on metal hip replacements as an alternative to total hip arthroplasty, and they concluded that the relatively new metal hip implants may not be worth the risk.

The assessment (PDF) is the third time the group has reviewed metal-on-metal hip implants, and the group says that questions and concerns about the technology that were present years ago are still important today.

Because of high revision rates and the risk of metallosis, caused by cobalt and chromium particles shed by metal-on-metal implants, the group concluded that “there is clearly no evidence that the potential benefits outweigh the potential risks.”

After they were introduced, metal-on-metal hip implants accounted for about 1/3 of the 250,000 hip replacements performed each year in the United States. Over the past two years, concerns have increased about metal hip replacement complications, resulting in use of the implants dropping to just 5% of the artificial hip market.

Research suggests that as the metal hip replacement ball and socket grind against each other, microscopic particles of cobalt and chromium are shed into the body, which results in metal poisoning. This metallosis may result in soft tissue damage, inflammatory reactions, bone loss, aseptic and local necrosis that may lead to the need for a hip revision surgery.

In May 2011, the FDA requested artificial hip manufacturers to provide more data on problems with metal poisoning and metal implants.

Attention on the metal-on-metal hip implant risks increased after the DePuy ASR hip recall in August 2010. The DePuy metal-on-metal artificial hip system is no longer available after more than 90,000 components were sold throughout the world.

More than 1,000 people have already filed a DePuy ASR hip replacement lawsuit due to complications caused by the recalled system. These lawsuits have been centralized in the Northern District of Ohio for pre-trial consolidation. To make matters worse, DePuy Orthopaedics additionally faces a growing number of DePuy Pinnacle hip lawsuits filed as a result of problems associated with their other metal-on-metal artificial hip implant. These lawsuits have been centralized in the Northern District of Texas, for pre-trial consolidation. To date a DePuy Pinnacle hip recall has not been issued, and these lawsuits also allege that these older system features similar design defects that increase the risk of early loosening or failure.