80 percent of failed metal-on-metal hip implants in study failed within two years

Metal-on-metal hip replacements are in the spotlight again. A new study, published in the latest issue of the Orthopedics Journal, states that metal hip implants barely last two years before failing.

Researchers reviewed the records of 41 men and 39 women who underwent revision surgery for a failed metal-on-metal hip replacement between 2003 and 2010. The researchers found that 78 percent of those revision surgeries occurred less than two years after the first operation and 92.5 percent within three years.

More than half of the patients needed revision surgery because the device loosened. According to the study, other common causes of failure included infection, allergic reactions to the metal, pseudotumor (false tumor) formation, dislodged liner, cup malposition, and femoral stem fracture.

The researchers feel that poor manufacturing and engineering are at fault and that medical staff should follow up with any patient implanted with the device.

Previous studies evaluating the safety of metal-on-metal hip implants found the metal implants can shed metal particles in patients’ blood and tissue. The long term consequences of this shedding can lead to metallosis, a condition that causes inflammation and weakened tissue.

Several manufacturers were forced to issue recalls due to high failure rates and complications associated with the devices. For example, Johnson & Johnson recalled 83,000 metal hip implants in 2010. The pharmaceutical giant was later accused of selling the implants for three years without proper clearance from the U.S. Food and Drug Administration.

The FDA is often blamed for manufacturers’ bad behavior. Due to its lenient and speedy approval program, device manufacturers can quickly market their devices without having to conduct pre-market testing if a similar product is already being marketed. Though the program is beneficial to manufacturers’ pockets, it’s not always so beneficial to consumers.