Johnson & Johnson (J&J) has more than one thousand law suits filed against it for its hip replacements, and now the FDA has peaked interest. The U.S. Food and Drug Administration asked J&J and 20 other replacement part makers to study whether its implants raise the level of metal in patients’ blood to dangerous levels.
The leading hip makers behind J&J are Zimmer and Stryker, according to a BMO Capital Markets report in February that said the worldwide hip replacement market would grow 3.2% this year from $5.28 billion in 2010.
A unit of J&J, DePuy Orthopaedics in August 2010 recalled a hip replacement system that had been implanted in 93,000 patients worldwide. DePuy cited unpublished data from the U.K. national joint registry that indicated a quite large failure rate of 12% within five years of implantation.
DePuy Orthopaedics issued a voluntary recall of its ASR XL Acetabular Hip System and DePuy ASR Hip Resurfacing System. The DePuy Orthopaedics ASR Hip System first became available in July 2003. DePuy hip systems have failed in approximately 1 out of every 8 surgeries, with patients experiencing pain, complications, and requiring additional surgeries after being fitted with the ASR Hip System.
There have been numerous complaints and lawsuits filed against Johnson & Johnson and DePuy Orthopaedics. Patients who underwent a hip replacement surgery and received a DePuy hip replacement system have complained of symptoms including swelling and problems walking nearing the five year mark after their surgery.
The FDA describes metal on metal implants and cites reports in medical literature of “a small number of patients in which high levels of metal ions in the bloodstream may have caused other types of symptoms or illnesses elsewhere in the body, including effects on the heart, nervous system, and thyroid gland.”
Metal-on-metal types of hip implants that were recently the subject of the DePuy hip replacement recall, but it’s important to remember that not all metal-on-metal implants have such high failure rates. Advantages that make metal-on-metal implants a desirable option include their longevity and the enhanced stability and range of motion they can provide to patients. The release of metal ions in the body is a concern, and this can be a serious problem if the patient is highly sensitive to metals.
There are also metal-on-plastic systems. The femoral head is constructed of metal while the liner is composed of polyethylene plastic. Standard polyethylene liners have largely been replaced by ones made of highly cross linked polyethylene. The reason for this is that plastic is highly susceptible to wear. Patients who are young and/or highly active will often need a revision procedure within seven to ten years due to this issue. This option may be a good one for those who are elderly or do not engage in much physical activity on a daily basis.
Finally in a hybrid technique, there are the metal-on-highly cross linked polyethylene systems. This configuration is the same as metal-on-plastic devices, but cross linking makes the polyethylene much more robust. One study found that there was more than a 95 percent decrease in wear when comparing these devices to ones in which the lining was composed of standard plastic. Therefore, these hip implants are a good choice for young, active patients and those who need to undergo revision procedures because of wear problems with the initial implants.
Written by Sy Kraft