A new study in BMJ , the British medical journal, has revived interest in the issue of the kind of materials best used for hip replacements.
Problems have long been reported from many quarters when metal is used to refashion both sides of the ball-and-socket hip joint. We wrote about one manufacturer’s defective product last year.
The trouble comes when the metal parts abrade each other, releasing tiny bits of metal into the surrounding tissue. Essentially, it’s metal poisoning, called metallosis, characterized by pain and inflammation that impedes the ability to walk.
In 2009, the FDA initiated a comprehensive evaluation of approved implants. And in May, the agency requested more information from metal hip replacement manufacturers to quantify and address the problem.
Now, the FDA-sponsored study results in BMJ “do not indicate any advantage for metal on metal or ceramic on ceramic implants compared with traditional metal on polyethylene or ceramic on polyethylene bearings.”
That means earlier technology, which used ceramic or, essentially, plastic, are just as effective as the latest technology-metal. Although metal conferred no advantage, the study showed, it was burdened with more problems that not only left patients uncomfortable and mobility-challenged, but possibly at a greater likelihood of needing follow-up surgery.
Many lawsuits have been filed involving metal-on-metal hip implants.
The study examined 3,139 hip-implant patients and data from more than 830,000 operations worldwide. “Evidence on implant revision did not favor metal on metal implants,” researchers wrote.” There is limited evidence regarding comparative effectiveness of various hip implant bearings, and the results do not indicate any advantage for metal on metal or ceramic on ceramic implants compared with traditional bearings.”
More than 700,000 joint replacements are performed every year in the Unites States; about 270,000 are hip replacements, and that number is expected to double over the next decade. The cost of the procedure is expected to rise as well.
Joint replacement, the study notes, is a generally successful operation that addresses a significant health issue. The recent popularity of metal is due in part because it enables the use of larger femoral heads (top of the thigh), which supposedly reduces the risk of dislocation and improves the functional outcomes in younger patients. But its use for older patients, according to one study, was popular as well, with 1 in 3 such patients receiving metal-on-metal implants.
Hip replacement surgery can be a godsend for people suffering from this degenerating joint problem. But if you’re scheduled for the procedure, ask your surgeon which device he or she is planning to use, and research its history. If it’s a metal-on-metal device, at least seek a second opinion.