When it comes to the science of hip replacement surgery, DePuy Orthopaedics, Inc., a subsidiary of Johnson & Johnson, is a U.S. market leader. DePuy began selling the ASR XL System in the United States beginning in 2005, for use in total hip replacement surgeries. On August 26, 2010, DePuy issued a voluntary recall of the system amid claims that it is a defective product causing serious health issues. Johnson & Johnson claims that the voluntary recall demonstrated its unwavering commitment to patient safety. However, recently released information suggests that DePuy and Johnson & Johnson were aware of the safety issues with the ASR XL System long before it yielded to pressure to recall the product. As a result, unsuspecting surgeons continued to implant the ASR XL System in their patients, only to find - in short order - that those same patients suffered complications from the implant and required hip revision surgery. To date, over 1,000 patients have filed lawsuits in connection with the DePuy ASR XL System. And because 37,000 units have already been implanted in the United States alone, that number is only expected to grow.
ASR XL System: Design Flaws and Patient Injuries
The DePuy ASR XL System is a "metal-on-metal" hip replacement system that uses a cup in the hip joint and a metal ball that connects to the femur. DePuy marketed this product specifically to young women and to those who live an active lifestyle, claiming that the product was tough and durable. Studies and research have discovered otherwise.
Design flaws in the ASR XL System have led to various complications. For example, dislocation of the replacement joint may occur when the hip is rotated at an angle 10 degrees less than competing products. Due to the unique design of the cup, a reported 30% of surgeons have had difficulty inserting the cup at the angle recommended by the manufacturer. This "error rate" is far greater than the industry standard. Additionally, the ASR XL System offers the lowest coverage (meaning the area in which the hip joint can rotate) and the lowest clearance (meaning the distance between the surface of the interior of the cup and the ball rotating within the cup) of any similar product currently on the market. Low clearance results in a minimal fluid-film barrier to protect against friction, leading to increased breakdown of the cup, resulting in joint pain, medical complications, and, ultimately, failure of the product.
The list of medical conditions that may arise is sobering. Among the most serious concerns is the product's release of metal particles into the tissue surrounding the implant, caused by friction between the ball and cup. These metal particles can have numerous harmful effects, including an increase in the levels of chromium and cobalt in the patient's blood stream (which can potentially result in various other serious complications and health risks) and necrosis of otherwise healthy tissue in the area surrounding the implant. With enough exposure to the metal ions, pseudo tumors may develop in the adjacent area, potentially leading to cancer. The list does not end here. Patients can suffer pain, immobilization from dislocation of the joint, bone fractures, and infections. It therefore becomes necessary for a patient implanted with a DePuy ASR XL System to undergo explantation (removal) of the existing system and reimplantation with a replacement system, presenting a new risk of infection and an increased risk of future dislocation.
How Has DePuy Responded?
Prior to the August 2010 recall, DePuy did little to address the issues presented by its ASR XL System. Interestingly, the ASR XL System never underwent the rigorous Food and Drug Administration (FDA) review and testing process to which such products are typically subject. Instead, DePuy was able to legally circumvent the standard FDA approval process by demonstrating that the ASR XL System was "substantially similar" to another metal-on-metal total hip replacement system already on the market.
Clearly, there were many indications that DePuy's product was unsafe well before August 2010. In 2007, a study by the Australian Orthopedic Association's National Joint Replacement Registry provided DePuy with preliminary warnings regarding many of the failures previously outlined, and warned that the internationally-sold equivalent to the ASR XL System was twice as likely to fail as other systems on the market. Nevertheless, DePuy continued to sell the ASR XL system.
Between 2007 and 2009, in the United States alone, the FDA received an increasing number of reports regarding the adverse affects of the DePuy ASR XL System, rising from a reported 87 to as many as 426. These numbers likely understated the actual number of issues with the product, as such reports are entirely voluntary. Yet DePuy and the orthopedic team that developed the device continued to assure patients and doctors that the ASR XL System was safe. In 2007, DePuy faced criminal charges in New Jersey for kickback payments to doctors who used DePuy knee or hip replacement systems with their patients. Investigations revealed that doctors on DePuy's orthopedic team, who continued to maintain that the ASR XL System was safe, were receiving generous compensation from DePuy, including $552,000 to one doctor and $3 million to another between 2009 and 2010. DePuy eventually settled these charges to the tune of $84.7 million.
Since this information has come to light, doctors have been increasingly recommending that the DePuy ASR XL Hip Replacement Systems be removed from patients who currently have the device implanted. One reason for the recommendation is patients' ongoing complaints of pain and hip dislocation. Another reason is that patient with the existing ASR XL System are showing dangerously high levels of chromium and cobalt in their bloodstreams. Some studies have shown that the longer the body is exposed to these metal ions, the greater the risk of cancer to the patient. However, these levels can be detected only with a specially ordered blood test. Thus, asymptomatic patients and their physicians may not be aware of the harmful effects the product may be causing while the ASR XL System remains implanted.
Patients currently implanted with the DePuy ASR XL System should contact their surgeon to determine whether the implant is a DePuy ASR XL System, and if so, request that the necessary blood tests be ordered to monitor the patient's chromium and cobalt levels. Patients would also be well-advised to discuss revision surgery with his or her surgeon, due to the high risk of product failure and associated complications.
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