- Historical Example of Surgical Innovation 2: Arthroscopic Knee Surgery
Arthroscopic lavage or débridement is frequently the recommended therapy when medicinal options fail to relieve pain from osteoarthritis of the knee. At a price of approximately $5,000 for each of the more than 650,000 operations performed in the US annually, this procedure represents commerce of more than $3.25 million a year. Patients often report relief of symptoms following the surgery, however, its therapeutic function and efficacy are poorly understood. Moseley et al. of the Houston Veterans Affairs Medical Center revisited this problem in 2002 by conducting a randomized, double-blind, placebo-controlled trial that assessed the efficacy of arthroscopic surgery of the knee in relieving pain and improving function in patients with osteoarthritis. Prior research had almost all been uncontrolled and examined patients for whom arthroscopic procedures were a last resort. The results of this inquiry raise a number of issues on the use of placebo groups in surgical research.
The study involved 180 osteoarthritic patients who were arbitrarily selected to receive arthroscopic débridement, arthroscopic lavage, or placebo surgery. Patients assigned to the placebo arm received skin incisions and underwent a simulated débridement surgery without insertion of the arthroscope. Researchers measured the outcome of each patient over two years using five self-reported scores and one objective test of walking and stair climbing. Results for 165 subjects were analyzed. It was found that there was no evidence to indicate that lavage or débridement held any therapeutic advantage over the placebo procedure relating to reported knee pain or self-reported function. The objective function measurements at certain points were in fact worse in the débridement group than the placebo group, though the final scores were not statistically different for any arm. The findings expose the substantial threat of placebo effect in surgical studies, and why researchers must reevaluate their methods for testing the efficacy of surgical procedures performed solely for the relief of symptoms.
Results from this investigation could not have been generated without use of a placebo arm, illustrating how sham surgery can be an essential tool for surgical researchers. Sham surgery often raises concerns because control subjects receive no possible benefit from the procedure, yet are exposed to the risks associated with the experimental operation. It is not beyond reason then why many would react with cynicism to such a method, since ostensibly it involves harming certain research subjects. Critics claim that this violates the rights of human research subjects, amounts to injury, or that the problem of placebo effect is exaggerated. This study, however, emphasizes reasons for performing sham surgery in clinical trials when necessary.
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Arthroscopic Surgery Research by Moseley et al. |
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For trials involving sham surgery, the informed consent process is especially important because subjects must understand they may be harmed by the procedure with no potential therapeutic benefit. For instance, Moseley et al. required subjects to write out that they may receive the placebo procedure and that the procedure will not benefit their knee arthritis. Understandably, about 44% of patients decided not to participate.