Just over a decade ago, when orthopedic device manufacturers began making hip implants with all metal parts, some researchers warned that the metal-on-metal designs could pose a health threat. They knew that all artificial hip implants, whether made of ceramic, plastic, metal, or a combination of materials, shed particles into the blood and tissue through normal wear and tear.
But, according to a New York Times report, “those warnings were not heeded, and now doctors and patients face a growing public health problem as one of the country’s biggest medical device failures unfolds.” At the same time, there has been a surge in the number of patients receiving metal-on-metal hip implants, and now a number of them are experiencing acute and systemic illnesses related to elevated levels of metal in the body.
A new Canadian study published in a December volume of the journal Orthopedics not only reaffirms the known dangers of these all-metal hip implants, but indicates medical professionals and patients themselves may not be fully aware of all the problems metal hips can pose years down the road.
The study looks at a 54-year-old female patient who developed a swelling in her leg five years after she received a metal-on-metal hip replacement. Walking exacerbated the swelling in her leg. Further analysis of the patient found that an accumulation of metallic debris from the hip device in her blood and tissue caused a bursal cyst that compressed her femoral vein. A biopsy on the cyst showed it contained high levels of chromium and cobalt.
The patient had her metal hip implant replaced with a ceramic-on-ceramic hip device, and doctors found no signs of a recurrence of the cyst a year after the surgery.
The researchers noted that, “Metal-on-metal bearings of the hip are associated with elevated concentrations of metal ions in the hip joint and systemically,” and an excessive amount of heavy metals in the body can lead to a number of adverse reactions, including fluid build-up, lesions, bone fracture and decay, cysts, and tumors.
DePuy Orthopedics, a division of Johnson & Johnson, recalled its ASR hip devices, the ASR XL Acetabular System and ASR Hip Resurfacing System in August 2010 after medical data from the U.K. showed that 12 to 13 percent of the metal hip devices failed within five years. As each year passes, more and more patients implanted with the recalled DePuy devices file complaints against the company, alleging injuries associated with device failure and metal poisoning.
In May 2011, the FDA ordered DePuy and all other manufacturers of metal-on-metal hips to conduct further studies of the devices to determine how frequently they failed and what impact they had on the health of patients implanted with them. However, the results of those studies aren’t expected to be fully known for several years.