August 16, 2022

In Medicine, New Isn’t Always Improved

But the promise of innovation can also prove a trap, a situation now playing out with dire consequences for possibly tens of thousands of people who received artificial hips intended to let them remain active.

The implants, known as metal-on-metal hips, were regarded by device makers and surgeons as a major advance over previous designs that used both metal and plastic. Now federal regulators and medical researchers are scrambling to determine how many implant recipients have been injured by the devices, which can shed dangerous metallic debris through wear.

In a highly unusual move, the Food and Drug Administration last month ordered manufacturers of all metal hips to undertake emergency studies of patients. And lawmakers and others are now calling for a tightening of how the F.D.A. scrutinizes new implants — both before and after they are sold.

A review of the medical world’s embrace of the metal-on-metal hips over the past decade — including interviews with doctors, industry consultants, regulators, medical experts and patients — shows how innovation’s lure led almost everyone to seize on a product promoted as a breakthrough without convincing evidence that it was better or even as good as existing options.

“As a non-American, I don’t completely understand it, but there is a phenomenon in the U.S., the latest and the greatest,” said Dr. Henrik Malchau, who practiced as an orthopedic surgeon in Sweden before going to Massachusetts General Hospital in Boston. “There was a patient demand to get these implants on the misconception that the latest was the best.”

For many manufacturers, the constant churning of new products can be a business necessity, a way to gain an edge on competitors while maintaining or even raising prices. But in recent years, a host of supposed innovations have imploded not long after introduction.

Several heavily promoted artificial spinal disks, claimed by their makers to be major innovations, proved no better than previous ones. After the blockbuster diabetes drug Avandia was linked to heart attacks, a federal study concluded that older drugs were safer and worked better for most patients. And a new heart device component from Medtronic started fracturing after it was implanted in more than 200,000 patients; at least 12 people died in connection with that product.

Some experts, like Dr. Malchau, said they used a special type of metal-on-metal implant known as a resurfacing device in specific patients — mainly taller, middle-age men — because data showed that they worked in that small group. But as with many innovations, metal hips were marketed to all comers. For example, about 65 percent of the implants went to women and older patients, according to an estimate by a consulting firm, Exponent Inc. As it turned out, those two groups appear most prone to failures involving the devices.

“The vast majority of the ‘innovations’ on which we have spent money with respect to orthopedics over the past two decades have not resulted in improved patient outcomes,” said Dr. Kevin J. Bozic, an orthopedic surgeon and professor at the University of California, San Francisco, who has written about artificial joints’ impact on health care costs.

Last year, DePuy, the orthopedics division of Johnson Johnson, recalled one of its all-metal hips, the ASR, which was failing at a high rate. Another manufacturer, Zimmer Holdings, also briefly halted sales of one of its metal models, the Durom.  DePuy, Zimmer and other companies and doctors have said that most patients who received metal hips have done well.

Experts like Dr. Bozic suggest that big gambles on innovation are justified in dealing with diseases, like some cancers, where current treatments are ineffective. But they say that calculus should shift sharply when existing treatments are highly effective, and that doctors need to use better yardsticks before embracing new technologies in those cases or adopt changes slowly.

THE modern artificial hip, which was developed by a British surgeon, Dr. John Charnley, in the 1960s, uses a relatively simple design. A metal “ball” made of cobalt and chromium replaces the top of the thigh bone, while a “cup,” typically made of plastic, serves as an artificial hip socket. By the 1990s, the devices were considered highly effective, with studies then finding that implants still worked a decade after surgery in 95 percent of patients.

Metal-on-metal implants, in which the cup is also made of a metal alloy, had been tried during those early decades, but were largely abandoned after tests found that patients had metal particles in their blood or organs, raising concerns about long-term health risks like cancer.

Article source:

Speak Your Mind