There's no evidence to support the safety or effectiveness of nearly 8 percent of all components used in hip-replacement surgeries in England and Wales, a new study finds.

The University of Oxford researchers said the current regulatory process "seems to be entirely inadequate" and called for a new system for introducing new devices.

The team's review of data revealed that more than 10,000 of the nearly 137,000 components used in primary hip replacements in England and Wales in 2011 had no solid evidence of being effective.

These components included about 150 cemented stems, more than 900 uncemented stems, more than 1,700 cemented cups and nearly 7,600 uncemented cups, according to the study, which was published online Dec. 19 in the journal BMJ.

In a journal news release, researcher Sion Glyn-Jones and colleagues said their findings are of great concern, "particularly in light of the widespread publicity surrounding recent safety problems with regard to some resurfacing and other large-diameter metal-on-metal joint replacements."

The researchers said their results likely underestimate the actual extent of the problem.

"This study shows that the need still exists for an improved and more rigorous approach to regulation of devices to avoid devices with no available evidence being used in a widespread and uncontrolled manner," the study authors said.

Tighter controls are needed, Aaron Kesselheim and Jerry Avorn, of Harvard Medical School, said in an accompanying journal editorial.

Researchers criticize FDA for lax oversight; agency defends its approach

Researchers criticize FDA for lax oversight; agency defends its approach Credit: HealthDay

Doctors who use new devices that "have little or no evidence of superiority over existing products need to be educated about the implications of their choices," Kesselheim and Avorn said. "They should also ensure that their patients know about the benefits and risks of the new -- but often unproved -- medical devices they are receiving."

More information

The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases has more about hip replacements.

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