Metal-on-metal hip implants made by Johnson & Johnson and Zimmer Holding Inc. need more consistent testing to help lower high failure rates that lead to risky replacement surgeries, a report by regulators said.
The Food and Drug Administration staff said agency advisers meeting on the devices this week should consider when and how patients should undergo imaging and ion testing to measure the metal’s effect on surrounding tissue, according to documents posted on the agency’s website today.
The Food and Drug Administration will convene an advisory panel meeting June 27 and 28 to discuss the implants, which have been the subject of thousands of patient lawsuits. The metal devices have been linked to almost 16,800 adverse events in the U.S. from 2000-2011, regulators said in a report last week.
“In general, the overall use of metal-on-metal has diminished quite a bit,” Matthew Taylor, an analyst with Barclays Capital Inc., said by telephone. “Physicians are cautious about using these.”
The DePuy unit of New Brunswick, New Jersey-based J&J began recalling hip devices in 2010, after more than 12 percent failed within five years. About 74 percent of 12,137 incident reports to the FDA in 2011 involved that device, the agency reported.
J&J faces more than 6,000 lawsuits related to the metal-on-metal hips in federal and state courts. In May 2011, the FDA asked hip implant makers to conduct post-market studies.
While the majority of patients with the implants do well, surgeons need to know what to do if they exhibit high levels of metal in their blood, said Joshua Jacobs, a surgeon and vice president of the American Academy of Orthopaedic Surgeons, in a telephone interview. Metal ions can damage tissue and require revision surgery to replace the old device.
The FDA’s advisers have been asked to consider the role of imaging in patients who exhibit signs of problems and those that don’t. They will also weigh who should be tested for metal ion levels, and how the result would be used by the physician.
“Soft tissue imaging of the hip may be the most effective means to identify a soft tissue reaction in a patient,” FDA staff said in the document.
Metal-on-metal hip implant use peaked in 2006 and 2007 at an estimated 30 percent of the market and is now about 10 percent, Barclay’s Taylor said. Other implants include those made of ceramic and polyethylene. The ball and socket are each made of metal on the implants in question.
Adverse event reports in 2011 totaled 12,137 for the metal-on-metal devices, compared with 6,332 associated with other types of hip implants, according to an FDA document. The most-reported side effect was revision, meaning surgery to remove or replace the implant. Revisions totaled 14,131 in metal-on-metal hip implants followed by 8,704 reports of pain.
FDA staff assessed all available literature to attempt to compare metal implants to the other versions and determined the rate of replacement surgery for metal implants “is likely not lower” than the rate associated with other implants, according to the documents posted today.
A review of international and U.S. registries also found higher rates of revisions for metal implants. The national registry in England and Wales found the rate of replacement surgeries after five years for metal-on-metal implants was 6.2 percent, almost three times as high as other versions. A registry of implant procedures in Minneapolis and St. Paul, Minnesota, established by provider HealthEast Care System found metal-on-metal systems were associated with a four times higher occurrence of revision surgeries than metal and polyethylene.
If the FDA restricts metal-on-metal implants, companies such as Biomet Inc., based in Warsaw, Indiana, won’t be significantly affected, Taylor said.
“Most of the companies have a full line of hip products they can sell so they’d just be swapping it out with the other hip products,” he said.