Metal-on-Metal Hip Replacements May Be Linked to Cancer Risk: Report

A study currently underway is expected to reveal that side effects of metal-on-metal hip replacements may cause genetic damage, which could lead to an increased risk of cancer. 

According to a report by the U.K.’s Telegraph, a study to be presented next month at the British Hip Society conference will include findings that suggest the metal particles shed by metal-on-metal hip replacements could cause chromosomal changes, which may lead to kidney cancer and bladder cancer.

The findings are the latest blow to the safety of the once-popular implant designs, which have been the subject of massive recalls and a number of product liability lawsuits filed by individuals who allege that they are prone to fail within a few years after surgery.

The study, which is currently underway, involves research on 72 patients who received all-metal hip implants. Researchers are expected to say that 17 of those patients had genetic damage to their bladders and three were diagnosed with cancer. The researchers say the numbers suggest a significant portion of metal hip implant patients could be affected, with one in five showing some genetic damage.

The most likely culprit of such damage is metal debris made up of cobalt and chromium, which is shed into the body when metal hip implant parts rub against each other. The particles have been linked to tissue damage, tumors, high metal ion blood counts and metal blood poisoning, known as metallosis.

Already some experts suggest problems with metal-on-metal hip replacements could cost medical device manufacturers billions in legal costs. If 20% of all metal hip implant recipients actually suffer genetic damage due to metallosis from their implants, it could lead to massive litigation on a global scale.

Some companies, like DePuy Orthopaedics, a division of Johnson & Johnson, already face a staggering number of metal hip implant lawsuits. In August 2010, a DePuy ASR metal hip implant recall affected 93,000 implants worldwide and about 40,000 sold in the United States.

Approximately 3,500, of those individuals who received the implant in the U.S. have already filed a DePuy ASR hip lawsuit against Johnson & Johnson and DePuy. As more hip implants fail over time, the number of people filing product liability claims against manufacturers is likely to increase.

At the time of the recall, DePuy and Johnson & Johnson, their parent company, suggested that about 12% of the ASR hip implants will fail within five years. However, more recent data from the National Joint Registry for England and Wales indicates that nearly a third of patients will experience problems within six years and other estimates suggest that as many as half of all individuals who received the recalled hip system may eventually experience loosening or failure of their implant.

In May 2011, the FDA asked device manufacturers to obtain more information about the level at which the metal particles shed by hip replacements becomes dangerous, how much metal they actually shed and what the potential side effects of metallosis are.