New Hip Implants No Better Than Older Ones, Study
TUESDAY, Nov. 29 (HealthDay News) -- No matter the material, all
types of hip replacement devices appear to work the same, a new
Specifically, the newer, metal-on-metal implants seem to be no
more effective than older implants and may sometimes even be more
problematic, the researchers said.
"Metal-on-metal and ceramic-on-ceramic hip implants might not be associated with any advantage, compared with traditional bearings such as metal-on-polyethylene or ceramic-on-polyethylene," said lead researcher Dr. Art Sedrakyan, director of the Patient-Centered Comparative Effectiveness Program at Weill Cornell Medical College in New York City.
There is some evidence from three large national registries that
higher rates of replacement surgery are associated with
metal-on-metal implants, compared with metal-on-polyethylene
implants, Sedrakyan noted.
However, the bottom line for Sedrakyan is that there is not
enough information about these devices to really tell if one type
is better or safer than another.
"There are very successful implants on the market today for hip replacement," Sedrakyan said. "We need to have stronger data on improvement in clinical outcomes for new hip implants," he said.
Even for newer implants such as metal-on-metal or
ceramic-on-ceramic bearings, their advantage over traditional
implants is not clear, Sedrakyan added.
The report was published in the Nov. 29 online edition of the
In the United States alone, almost 400,000 people each year have
hip replacement surgery, Sedrakyan noted. A small percentage have
surgery to fix problems with previous hip replacements. Often these
operations occur within 10 years after initial surgery and are
needed because of infection, dislocation, wear, instability,
loosening or other mechanical failures.
Although the cost of a hip replacement varies by location and
insurance, the average cost in the United States ranges between
$35,000 and $40,000, with the newer devices costing on the high end
of the spectrum, according to a 2006 report from the nonprofit
Integrated Healthcare Association.
Older hip implants made with metal-on-polyethylene or
ceramic-on-polyethylene surfaces are associated with low failure
rates. However, newer metal-on-metal hip implants have been linked
with severe cases of accumulation of metal ions in patients'
In 2009, the U.S. Food and Drug Administration began a review of
the evidence for the safety and effectiveness of approved hip
Working with the FDA, Sedrakyan's team looked at the safety and
effectiveness of various types of hip implants in 18 studies
including more than 3,000 patients and 800,000 operations.
The investigators found no difference between the various types
of implants in terms of the patients' quality of life or ability to
Commenting on the study, Dr. Peter Cram, an associate professor
of medicine in the division of internal medicine at the University
of Iowa Carver College of Medicine, said that "the study highlights
a critical issue in joint replacement surgery, which is there is
not a lot of good data."
Cram noted that it is "shocking" that there are so many hip
replacements done with so little data about which implants are
For patients, the best way of ensuring they are getting the best
hip replacement they can get has really nothing to do with the
device, Cram added. "You probably want an experienced surgeon, who
does lots of these procedures, in a hospital that does lots of
these procedures," he said.
Dr. Joseph Zuckerman, professor of orthopedic surgery and chair
of the orthopaedic surgery department at NYU Langone Medical Center
in New York City, said that "this study confirms what many surgeons
already practice -- that in the pursuit of providing the best
outcome, a surgeon must base his or her treatment recommendation on
important factors that include each individual patient's health
status and lifestyle, their own clinical experience, the documented
evidence about outcomes and the available technology."
For more on hip replacement, visit the
U.S. National Library of Medicine.
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