Metal-on-Metal Hip Failures Two-to-Three Times Higher Than Other Implants

According to recent information released by groups representing orthopedic surgeons, metal-on-metal hp replacements appear to be two-to-three times more likely to fail when compared to other types of artificial hip systems.

In this month’s issue of the Journal of Bone and Joint Surgery, the American Association of Hip and Knee Surgeons, the American Academy of Orthopaedic Surgeons, and The Hip Society issued a consensus statement warning about the risk of problems with metal-on-metal hips, which have been linked to a number of recalls and lawsuits in recent years.

“It has been estimated that since 1996 more than 1,000,000 MoM articular couples have been implanted worldwide,” according to the statement. “However, with increasing clinical experience, the national joint registries have recently reported the failure of total hip arthroplasty (THA) with MoM bearings to be two to threefold higher than contemporary THA with non-metal-on-metal bearings.”

The statement points out that in addition to actual catastrophic structural failures, adverse tissue reactions caused by metal debris shed by metal-on-metal hip implants is also being recognized as an important reason for the high failure rates.

While the consensus paper acknowledges that each patient has individual needs and does not outright call for other orthopedic surgeons to never use metal-on-metal hip systems, the statement may be the final blow for metal-on-metal designs, which rose to prominence several years ago under the belief that they would be more durable and more appropriate for young, active artificial hip recipients.

After the new hip design gained widespread use, a number of orthopedic surgeons began expressing concerns over the metal ball-and-socket hip designs when they started to see a high number of their patients return due to failures, tissue reactions and other problems. Surgeons noted that as the metal pieces rub against each other during normal use, cobalt and chromium debris may be shed into the body. This can lead to catastrophic failures and there were concerns that the debris was causing metallosis, a form of metal blood poisoning, and leading to the development of pseudotumors and dead tissue around the implants.

The issue gained national attention in August 2010, following a recall of the Depuy ASR XL Acetabular hip replacement and resurfacing systems. DePuy Orthopaedics, a division of Johnson & Johnson, announced that the artificial hips had a failure rate of up to 13%. That number has been signficantly revised over the years, with some experts and analyses predicting about a third of the DePuy ASR hips will fail within six years.

Following that recall and high failure rates involving other metal-on-metal hip implants, surgeons began to quickly back away from the use of the design, and this month’s consensus statement may result in many orthopedic surgeons swearing off metal-on-metal hip replacement systems entirely.

Manufacturers continue to face thousands of metal-on-metal hip replacement lawsuits brought by individuals nationwide. While hip implants are typically expected to last 15 to 20 years, most of the plaintiffs allege that they experienced complications within a few years that result in the need for revision surgery.

More than 12,000 DePuy ASR hip lawsuits have been filed against Johnson & Johnson, and the manufacturer is expected to pay more than $2.4 billion to resolve about 8,000 cases under a recently proposed settlement program.

Similar lawsuits are pending against manufacturers of other metal-on-metal hip lawsuits, including the DePuy Pinnacle, Biomet Magnum, and the Wright Medical Conserve Cup .