Patients who have arthroscopic surgery for arthritis in their knees may feel better even though the surgery didn't help, a new study suggests.

A team of surgeons in Texas tested the procedure by performing the surgery on 180 patients with osteoarthritis in the knee. Two-thirds got two different types of the surgery.

But for a third, the surgeons faked it – they went through the motions of giving a tranquilizer, making three incisions and pretending to do the surgery.

All participants in the study had to sign their chart to show they understood they might receive the placebo surgery, which would not help their arthritic knee.

Most arthroscopic surgery on the knee is done to repair injured ligaments and cartilage, which doctors say is useful. The experiment was designed to see whether the surgery helped reduce pain and increase mobility in patients with an arthritic knee.

The researchers found patients who underwent the placebo surgery were just as likely to report pain relief as those who received the real procedure. It seems for osteoarthritis patients, the relief is all in patients' heads.

Dr. Bruce Moseley

"I don't believe that arthroscopic surgery for osteoarthritis of the knee is any more beneficial than a placebo effect, and I don't recommend it," said Dr. Bruce Moseley, an orthopedics professor at Baylor College in Houston and one of the study's co-authors.

Former skier Todd Brooker of Collingwood, Ont., has had 13 knee surgeries for injuries and arthritis that developed after a fall in January 1987 that ended his skiing career.

"My doctor would go in through the scope and he would basically vacuum stuff out of there and clean up that whole area," Brooker said. He said it's hard to accept that he feels better because of the placebo effect.

Dr. John Cameron

Provincial health ministers will have to re-think paying for surgery

Orthopedic surgeon Dr. John Cameron of Toronto said the study provides the ammunition he needs to convince osteoarthritis patients that the procedure doesn't work. "If it's isn't doing them any good, we shouldn't be doing it," said Cameron. "That's the message of this paper."

One of the study's investigators, Dr. Nelda Wray of the Houston VA Medical Center and Baylor College, said the study makes doctors question whether money spent on the procedures could be put to better use. Provincial governments will now have to determine if the procedure is just an expensive placebo.

The study appears in Thursday's issue of The New England Journal of Medicine.