"Any treatment for pain has an enormous placebo effect," said Dr. Gary Firestein, chairman of the Food and Drug Administration's Arthritis Advisory Committee and chief of rheumatology, allergy and immunology at the University of California at San Diego School of Medicine. "The response rates are generally in the 20 to 40 percent range for almost all studies, and higher percentages are associated with more aggressive and invasive approaches where the belief system is firmly entrenched."
That highlights the importance of conducting placebo-controlled trials for surgical procedures, but that undertaking involves considerable ethical issues due to the invasive nature of surgery. For example, questions about the ethics of sham surgery were raised following a study on surgical implantation of fetal cells to treat Parkinson's disease. All subjects had holes bored into their skulls, but only half were given any treatment with the cells.
The more benign nature of arthroscopy has lent itself to less criticism. Many experts agree that the design of the current study was fair by ethical standards and that in this case it was important to determine whether such a common procedure was indeed effective.
"More important is whether it was ethical to perform tens of thousands of these invasive procedures on patients without any documentation that it alters the natural history of disease, quality of life or functional outcome," said Firestein.
Effect on Practice and Policy
Because this is the first such placebo-controlled study on arthroscopy for osteoarthritis, it is too soon to say whether the findings of the study will have any major impact on insurance coverage or physician practice.
Aetna, one of the nation's largest health-insurance providers, currently covers the procedure and says it plans to have its medical directors review the information before it considers making any changes in coverage.
Other experts would like to see the results duplicated before instituting widespread changes. "I think this is an interesting study … I'd like to have a couple of other centers repeat [it]," said Tipton.
One issue that remains is whether these findings would hold true for women, as the current study was conducted only in men. "Since osteoarthritis of the knee is more prevalent in women than in men, it is not clear that patients in the community always fit the study criteria precisely," said Firestein.
As for Perez, no matter what future research may find, he is happy with how everything has worked out. "I can dance, I can go away fishing, I can play basketball and it doesn't bother me one bit. Everything is wonderful."