New data reveal increased rates of revision surgery associated with specific metal-on-metal hip implant replacement devices.
The data from Canada suggests that patients implanted with specific metal-on-metal devices are likelier to undergo revision surgery within five years, according to the Winnipeg Free Press. The all-metal devices—large-diameter modular metal-on-metal implants—experienced a 5.9 percent increased likelihood of failing within five years, compared to a 2.7 percent in people implanted with a metal-on-plastic device.
The data was released by the Canadian Institutes for Health Information and reveal that about three of every four hip replacements reported in the Canadian joint replacement registry were metal-on-plastic units; metal-on-metal hip replacements devices comprised nine percent of the procedures recorded in the registry.
In the United States, metal-on-metal hip implants, as a class, have become the subject of safety concerns in the orthopedic community. These devices were approved using the U.S. Food and Drug Administration’s (FDA) fast-tracked 510(k) approval route, which bypassed clinical testing. Now, studies reveal that metal hip replacements tend to fail more often than other implants.
The hip implants were created for greater durability and longevity and with the intention that the seemingly stronger components would be far superior over their more traditional counterparts constructed with plastic or ceramic elements. In recent years, the metal devices have come under fire for failing at unexpectedly high rates and leaving patients with significant and, often, life long injuries.
Some experts say that European and American regulators worked to ensure patients were unaware of the devices’ risks and many have criticized device makers for placing profits before patient safety. For its part, the FDA recently issued new guidelines to patients implanted with all-metal hip replacements. Among other things, the agency advised that physicians conduct physical examinations, diagnostic imaging, and metal ion testing, as needed. The agency also proposed stricter regulations that would require manufacturers to prove the implants are safe and effective before selling them. From a legal standpoint, these changes are a big step in attempting to hold manufacturers responsible for dangers associated with their products.
The data seen in Canada is not typical in other countries. In Canada, orthopedic surgeons took a different approach that has been met with praise, Dr. Michael Dunbar, an orthopedic surgeon from Halifax and co-chair of the joint replacement registry, tells The Winnipeg Free Press. “It was the right side of the street to be on, for sure,” Dunbar says. “It was the fact of the matter that in the United States in the late 2000s almost 45 percent of every male in the country (who got a hip replacement) got metal-on-metal. So this is why it’s such a big issue in the United States.”
The difference between the two countries, says Dunbar, is that Canada has a joint replacement registry that, while voluntary, is moving toward mandatory reporting, at least in British Columbia and Ontario, for these procedures. “We have a voluntary system and until recently we’ve been down around 50 percent. We think that all implants should be registered because this is important. We’re spending the nation’s treasure on this stuff. This is a top health care priority in Canada,” Dunbar tells The Winnipeg Free Press. The data involved nearly 60,000 hip replacements conducted in Canada between 2003 and 2011; Quebec data were not included.