Yet another metal-on-metal hip replacement device is in the news for premature failures and serious complications. Last year it was the DePuy ASR system. Now it is Wright Medical Technologies’ CONSERVE Plus Total Resurfacing Hip System.
The FDA approved the CONSERVE system for commercial production and distribution in November of 2009, just two short years ago. And now it’s effectiveness—and more importantly, its safety—is already in question. So what exactly was that FDA approval process?
In the case of the CONSERVE system, the FDA started review in 2004 on an expedited basis, citing the fact that this type of product “may offer advantages in safety and effectiveness over existing alternatives” for treating patients with hip injuries and disorders. As part of that process, the FDA provides information on the safety and effectiveness data that is related to the product. This information includes, among other things, information on both preclinical laboratory and clinical studies conducted in relation to the product and how it performs; notably, these studies are conducted by the company requesting approval—in this case, Wright.
In the FDA’s letter notifying Wright of their approval, the agency specified what exactly approval of the device meant and the ongoing responsibilities of Wright with regards to monitoring the safety and effectiveness of the CONSERVE system.
First, the hip replacement system must carry appropriate labeling that details what training or experience a medical practitioner needs in order to use the product. This requirement is aimed at ensuring the safe use of the product.
Second, Wright is obligated to provide the FDA with annual reports detailing, among other things, the number of devices sold and distributed. This information permits the FDA to assess how safe the product is or how frequently it is failing. In other words, when the FDA receives over 200 reports of adverse effects—as they have with the CONSERVE system—the FDA can assess how big of a proportion that is of the total number of products on the market.
Third, Wright agreed to conduct two different studies on its CONSERVE system in order to methodically assess its safety and effectiveness. One of these studies focuses on the long-term performance of the hip replacement system and the other is aimed at studying how the system actually works under “real world conditions”. The FDA specifies very specific terms for how both studies should be carried out.
Fourth, Wright has an ongoing obligation to report adverse events to the FDA. This means that if Wright becomes aware of their product causing death or serious injury or having malfunctioned in a way that poses a risk of death or serious injury.
Throughout all of this information, there are repeated—although buried—references to the risks that metal-on-metal hip replacement systems pose because of the release of small metal particles into the body. These specific risks are at the heart of the recent lawsuits related to the CONSERVE system and raise questions about just how much Wright knew about those risks before this product went on the market and then whether they effectively cautioned patients and practitioners.