Failure of Metal Hips

Story first appeared in The New York Times

In a troubling development for people with all-metal artificial hips, a registry that tracks orthopedic implants in Britain reported on Thursday that the failure rate of the devices was increasing.

The National Joint Registry for England and Wales said that an all-metal artificial hip once sold by Johnson & Johnson had failed in an estimated one-third of the patients who had been followed for the longest time. The device was recalled by the company last year.

The British registry also found that the early failure rate of some other metal-on-metal hips — ones in which both the ball and the socket components of an artificial joint are made of metal — was significantly higher than for those made from other materials, including a combination of metal and plastic.

While the patients tracked by the British registry are not in the United States, doctors and patients here pay close attention to the registry’s findings because no such body exists in this country, where there is far greater use of artificial hips and knees. Australia also keeps a registry.

There was already heightened concern in the United States about the all-metal hips. In the first six months of this year, the Food and Drug Administration received more reports about problems with the all-metal hips than it had in the previous four years combined, according to an analysis by The New York Times. In May, the F.D.A. took the unusual step of ordering producers of the devices to study how frequently they were failing and to examine the health implications for patients.

While traditional artificial hips typically last 15 years or more before they need to replaced, some of the all-metal models are failing in large numbers of patients within just a few years. Early failure rates for all-metal devices were far higher in women than in men, the British report found.

According to the report, the highest failure rates involved the Johnson & Johnson device, which is known as the Articular Surface Replacement, or the A.S.R. The registry is following about 2,100 patients who received a version of the device that is used as a traditional hip implant. That is also how the A.S.R. was used in this country.

Of those patients in the British group who received the device six years ago, about 29 percent have since had it replaced.

The percentage is slightly lower, about 17 percent, in patients who got the device five years ago, but that number could rise over the next year.

DePuy officials recalled the A.S.R. last year around the time that the previous report of the British registry was released.

Along with a traditional hip model, another version of the device was sold outside this country for use in an alternative hip replacement technique known as “resurfacing.” It was also recalled.

While it is difficult to draw direct comparisons between device failure rates in Britain and in the United States, the new registry findings appear to bode ill for patients here who received an A.S.R. About 40,000 of the 90,000 units sold worldwide were used in this country.

The British data suggests that complaints will continue to grow in the United States in coming years because the A.S.R. was used overseas before its adoption here.

The British data also shows that the failure rate for all-metal devices as a group, even when the A.S.R. is excluded, is accelerating faster than for traditional hip replacements.

Though immediate problems with the hip implants are not life-threatening, some patients have suffered crippling injuries caused by tiny particles of cobalt and chromium that were shed by the metal devices as they wore.

Such debris generation is also believed to be a cause of earlier device failure.

Until a recent sharp decline in their use, all-metal hip implants accounted for nearly one-third of the estimated 250,000 replacements performed in this country each year. According to one estimate, some 500,000 patients in this country have received an all-metal replacement hip.

In the case of devices used for hip resurfacing, which is popular among younger patients, a model known as the Birmingham Hip Resurfacing device had the lowest replacement rate at five years, the registry found.

However, the report noted that further studies needed to be performed to determine whether hip resurfacing conferred true advantages over standard hip replacement.