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By Gina
Kolata
An estimated 12% of Americans
aged 65 and older have osteoarthritis of the knee. A popular operation
for arthritis of the knee worked no better than a sham procedure in which
patients were sedated while surgeons pretended to operate, researchers
are reporting today.
The operation arthroscopic
surgery for the pain and stiffness caused by osteoarthritis is performed
on about 650,000 people in the US every
year, at a cost of about $5,000 per procedure, for a total cost of 3.3
billion dollars every year in the US.
It involves making three small
incisions in the knee; inserting an arthroscope, a thin instrument that
allows surgeons to see the joint; and then flushing debris from the knee
or shaving rough areas of cartilage from the joint and then flushing it.
Tests of knee functions revealed
that the operation had not helped, and those who got the placebo surgery
reported feeling just as good as those who had had the real operation.
Dr. Baruch Brody, an ethicist
at Baylor who helped design the study, described the surgery as a sham.
The study dealt only with arthroscopic
surgery for osteoarthritis, not with other common knee operations.
The 180 participants in the
study were randomly assigned to have the operation or to have placebo
surgery in which surgeons simply made cuts in their knees so the patients
would not know if they had the surgery.
The research began when an
orthopedic surgeon at the Houston veterans' hospital, Dr. J. Bruce Moseley,
who is now the team physician for Houston's two professional basketball
teams, approached Dr. Wray suggesting a study that would compare washing
the knee joint with washing and scraping in patients with arthritis.
Dr. Wray had a bolder idea.
"She said, `How do you
know that what you are seeing is not a placebo effect?' " Dr. Moseley
recalled. "My response was, `This is surgery.' She said, `I hate
to tell you this, but surgery may have the biggest placebo effect of all.'
"
Placebo studies of surgery
are almost never done. Many doctors consider them unethical because patients
could undergo risks with no benefits. Working with Dr. Brody, the ethicist,
the group tried to make the placebo treatment no more dangerous than daily
life. Still, of 324 consecutive patients who were asked to participate,
144 declined.
For those who agreed, the day
of surgery meant being wheeled into an operating room while neither they
nor any of the medical staff knew what their treatment would be. When
they were on the operating table, Dr. Moseley, who did all the operations,
opened a sealed envelope telling him whether the patient was to have the
surgery or not.
Those in the placebo group
received a drug that put them to sleep. Unlike those getting the real
operation, they did not have general anesthesia.
Dr. Moseley made small cuts
in their knees to simulate an operation. He bent and straightened the
knee and asked for surgical instruments, just in case the patient was
partly conscious. An assistant sloshed water in a bucket to make the sound
of a knee being flushed clean.
The paper in The New England
Journal is accompanied by two editorials. One, by Sam Horng and Dr. Franklin
G. Miller of the National Institutes of Health, asks whether placebo surgery
is unethical. The controversy, they wrote, comes because doctors assume
that patients in clinical research should not be put at risk if they cannot
benefit, and placebo surgery involves risk.
But, they say, clinical research
is different from medical therapy; its aim is not to help those in the
study but to help future patients.
To be ethical, they say, a
study with placebo surgery must meet three criteria: it must not place
patients at undue risk; the benefits of learning whether the surgery works
must be worth any potential risk to the patients; and the patients must
give informed consent.
In the current case, they wrote,
all those objectives were met and the study "exemplifies the ethically
justified use of placebo surgery."
New
York Times July 11, 2002
The
New England Journal of Medicine July 11, 2002;347:81-88, 132-133
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