DePuy Orthopaedics, a division of Johnson & Johnson, announced that it is recalling two types of hip implants because of higher-than-expected early failure rates.

The recall affects the ASR XL Acetabular System, which is used for total hip replacements, and the ASR Hip Resurfacing System, which is used in a newer kind of bone-conserving procedure.

The total hip replacement system was FDA approved and has been used in patients in the United States.

The hip resurfacing system has not been approved for use in this country, but according to company spokeswoman Lorie Gawreluk, some patients in the U.S. have gotten the implants through a clinical trial.

Also, people who have traveled outside of the U.S. for hip resurfacing or hip replacement procedures may have been fitted with ASR components.

A combined total of about 93,000 of the devices have been implanted worldwide.

DePuy said that it was issuing the voluntary recall after new data from a British joint replacement registry showed about 1 in 8, or around 12 percent, of those who received the implants needed corrective procedures, called revision surgeries, within five years.

That failure rate appears to be about twice the industry average, says Kevin J. Bozic, MD, an orthopaedic surgeon and vice chairman of orthopaedics at the University of California at San Francisco Medical Center, who has studied revision rates in hip replacement.

"It was a design failure that frankly wasn’t picked up until they were implanted in thousands of patients," Dr. Bozic says. 

"This really underscores the need to track outcomes in hip and knee replacement patients. We happen to be one of the only developed countries in the world that doesn't track joint replacements through a patient registry," he adds.

Most people who replace a hip or knee can expect their new implants to last for the rest of their lives. 

But in some cases, usually because of loosening, when the components detach from the bone, infection or dislocation, implants have to be removed and replaced in a revision surgery. 

Revisions are more complicated and costly than primary joint replacements because surgeons have less bone and more scar tissue to work with.

Signs that the implant may be failing include pain and difficulty walking.

But the company is advising people who know they have ASR implants to schedule follow-up appointments with their surgeons, whether or not they are experiencing problems. 

Doctors will evaluate how the implants are functioning and may give patients blood tests to check for signs of microscopic metal particles around the implant, a sign of abnormal wear. 

Dr. Bozic says the important thing for consumers to remember is that most implants, even the ones affected by this recall, function well and are safe.

But he acknowledges that this recall has already generated a lot of anxiety among people with hip replacements: "A recall is a huge deal."

He says his practice has already operated on people who have not been having trouble with their ASR implants, but who wanted to get them removed for fear of future problems.