A Johnson & Johnson subsidiary has recalled a metal hip implant used by thousands of younger patients after complaints of severe pain and system failure, and amid worries that the implants may be sending metal shavings into patients' bloodstreams, potentially putting them at risk for dementia and heart failure.
An investigation by WTVD, the ABC owned-and-operated station in Raleigh-Durham, North Carolina, found that the artificial hip, manufactured by DePuy Orthopaedics, may have a failure rate of 12 percent, but was approved by the FDA without a clinical trial.
Since it was introduced in 2003, DePuy has sold nearly 100,000 units of its ASR XL Acetabular Hip System, which was designed for younger and more active patients. Made of chromium and cobalt, the device consists of a cup that's implanted into the hip with a ball joint that connects to the leg.
Experts say, however, that if a surgeon doesn't get the cup inserted at just the right angle, the two parts can rub against each other. That can cause severe pain, and metal particles may shave off and get into the patient's tissue and bloodstream.
Patient Alison Pulito told WTVD that she had the device implanted because of long-standing hip problems. "I had childhood dysplasia in my hip," explained the 48-year-old mother of two. "In my twenties, I was skiing and I fell."
Surgery to repair cartilage only gave short-term relief.
"I couldn't really walk," she recalled. "I just decided it was time to take the next step and have a hip replacement."
A former healthcare consultant, Pulito thoroughly researched her options and chose the DePuy system, which was co-developed by then-Duke University surgeon Thomas Vail. ASR's chromium and cobalt metals promised to make it more durable than previous implants.
"Wear is a real problem for hip replacement. It probably causes the majority of failures over time," explained Dr. Michael Bolognesi, who is director of surgery in Duke's orthopaedic department. He scrubbed in with Dr. Vail on more than 200 ASR implants.
"Traditional hip replacement will have a metal ball and a plastic liner," he said. "Our hope would be that, with those younger patients, these hard-on-hard bearings might give them an advantage from a standpoint of wear."
"I sent emails to my surgeon saying I thank you so much for, you know, taking my pain away and giving me this opportunity to get on a bike with my kids and walk my dogs," Pulito recalled.
But five months after the operation, she says the pain was back.
"It was incredibly painful," she said.
And Pulito wasn't the only patient who had pain. DePuy says some 93,000 implants have been used in patients, and medical registries around the world report hundreds of patient complaints.
The complaints include system failure, which means the hip must be re-implanted. The national joint registry of England and Wales showed that within 5 years of a surgery, ASR implants used in those countries failed 12 percent of the time.
Some doctors say they also worry about the possibility of particles from the implants getting released into the bloodstream. That could cause deafness, dementia and heart failure.
"It's incredibly concerning," said Bolognesi.
DePuy now recommends that implant patients have a blood test to check for high levels of chromium and cobalt.