Over the past few years, DePuy Orthopaedics has experienced several setbacks concerning their artificial hip implants. The company, which is a subsidiary of Johnson & Johnson, had recalled two of their products in September 2010 due to a high rate of failure. Prior to this, Johnson & Johnson had declared that the products were safe. However, a recently discovered internal email, dated a year before the recall, indicates otherwise; in their correspondence, company executives discussed the Food and Drug Administration’s (FDA) decision not to approve one of the the artificial hip devices.
The recalled products, Depuy ASR XL Acetabular System and ASR Hip Resurfacing System, are considered “metal-on-metal” implants. Originally, it was thought that these types of artificial hips were an improvement over the previous metal-on-plastic implants because they supposedly offered better mobility and were more suitable for younger, more active patients. However, health professionals have suspected that the metal-on-metal interaction would cause the material to flake off, creating debris and causing inflammation and tissue damage in the body. There are fears over whether or not the metal particles can gradually poison one’s organs, increase the risk of cancer, or affect unborn children in pregnant women.
Concerned over the potential negative health impacts, the U.S. Food & Drug Administration (FDA) ordered all metal hip manufacturers to conduct studies of the product last May. This unusual move focused on the category of products, rather than a particular manufacturer. Nonetheless, DePuy’s high rate of failure, in which approximately 12 to 13 percent of patients needed a second procedure within five years according the New York Times, became a major focal point in the matter. Typically, artificial hips last for at least 15 years. According the New York Times, the National Joint Registry for England and Wales reported that the DePuy product had failed in approximately one third of sampled patients who were followed for the longest period of time.
Now, an email written by DePuy vice president Pamela Plouhar is likely to weaken the company’s defense and public image. The email stated that the FDA had refused to approve one of the resurfacing products based on the high rate of failure observed in the company’s clinical studies. Plouhar wrote “The team’s concern is that given the revision rate in the ASR group that we will still not be able to demonstrate non-inferiority, with additional downside risk”, cites the New York Times. The email also notes that additional data is not likely to help the case. The FDA-rejected device had been sold in other countries since 2003. Meanwhile, DePuy used a regulatory loophole to market a similar version of this product in the United States while the studies were still being conducted in 2005. Although the company isn’t legally required to release the FDA’s decision to the public, this discovery is likely to put them at a disadvantage during litigations. Currently, there are more than 5,000 lawsuits pending against DePuy.
In their latest medical device alert concerning metal-on-metal hip replacements, the Medicines and Healthcare products Regulatory Agency (MHRA) provides healthcare professionals with follow-up recommendations for patients who have received the implants. The recommendations consist of blood metal ion testing to detect chromium and cobalt levels and imaging techniques such as Metal Artefact Reduction Sequence (MARS) in patients whose implants are larger than 36 mm in diameter. Blood tests should be conducted every year during the life of the implant, followed up with the imaging test should high levels be detected.