A new study suggests that the recent technology for artificial hips and knees did not perform any better than older, less expensive designs.
The study, which draws on data from Australia’s orthopedic registry, covered implants introduced from 2003 to 2007 and was published this week. The findings are significant for patients in the United States because many of the new designs, like so-called metal-on-metal hips, are widely used here. Those implants, which have both a ball and cup made of metal, are expected to fail prematurely in tens of thousands of patients rather than lasting 15 years or more as artificial joints are supposed to do.
The Australian study showed that not a single new artificial hip or knee introduced over a recent five-year period was any more durable than older ones. In fact, 30 percent of them fared worse. The Australian study concluded that both patients and taxpayer-financed health care programs were paying a high cost because surgeons were using newly designed implants, introduced with little test data, over existing designs that had track records. ”Not only has the introduction of this technology been potentially detrimental to patient care, but the current approach may be an important driver of increased health care costs,” the review concluded.
Dr. Stephen E. Graves, the director of the Australian registry and a co-author of the study, said he believed that surgeons, hospitals and regulators should closely look at the review’s results. In the case of the all-metal hips, some experts say they believe that replacing them may cost companies, insurers and taxpayers billions of dollars.
”There needs to be a careful re-evaluation of current deficiencies in regulation,” Dr. Graves said in a recent e-mail.
The Australian review is part of a special issue of a medical journal, The Journal of Bone and Joint Surgery, devoted to studies that examine the benefits and the limitations of orthopedic registries. While America does not have a registry, the Food and Drug Administration is financing efforts to see whether data from sources like overseas databases and registries run by hospitals here can be used to better monitor device performance. Many experts argue that such efforts are essential because 700,000 Americans undergo hip or knee replacement every year, and that number is expected to increase sharply as the population ages. In a registry, information about a patient is entered into a database when he or she receives an implant. Then, when that patient undergoes surgery again to replace that device, more data is added. By looking at large numbers of patients followed in a registry, researchers can tell whether certain device models are failing prematurely at significantly higher rates.
But researchers in England, which has a registry, pointed out in another article in the same medical journal that a product-related disaster had likely already occurred before it was detected in a such a database. As a result, some experts say they believe that there must be greater scrutiny of implants either before or after they go on the market to detect problems earlier. Another review in the same issue found that the results of published studies that accompany the introduction of new implants could bear little resemblance to registry findings about a device’s success once it went into broader use. That problem occurs, the review by Australian researchers found, because surgeons involved in the original published reports are often involved in its development and may have a financial stake in them. In addition, such reviews tend to be short term. Some surgeons say they believe that one type of all-metal implant known as a resurfacing device is permitting some patients to remain more active. However, data indicates that such benefits are limited to one group of patients, namely larger, middle-aged men.
This month, bipartisan legislation was introduced in the Senate that could force manufacturers to track the performance of implants like artificial hips after they have been approved for sale. Proponents of the bill acknowledge that the measure faces an uphill fight. Both device producers and their allies in Congress have maintained that any additional F.D.A. regulations would slow the development and marketing of innovative products that benefit patients. For his part, Dr. Graves, the Australian official, said he believed that such arguments were misleading.
”The purpose of regulation is not to impede innovation but to ensure safety and effectiveness of medical devices,” he stated. ”This protects patients, but it also protects companies.”
New York Times December 23, 2011