Arthroscopic procedures, considered minimally invasive alternatives to open surgery, involve tiny surgical tools mounted on thin probes, which are inserted into the joint through a small incision. In patients with knee OA, arthroscopic surgery typically involves lavage, in which the joint is "cleaned" of particulate matter, and debridement, in which the surfaces of the bones are smoothed.
Sham surgery is considered one of the most effective ways of determining whether the result of a procedure is related to the procedure itself or to a placebo effect.
Researchers from the University of Western Ontario compared outcomes in 86 knee OA patients who underwent arthroscopic treatment and 86 control patients who did not. All patients received physical and medical therapy, including 12 weeks of supervised exercise.
At three months, the patients in the surgical group had significantly higher pain and function scores than the control group. However, there were no significant differences between the groups at six, 12 or 24 months. The findings were published in the Sept. 11, 2008 issue of the New England Journal of Medicine and presented last month at the annual meeting of the American Academy of Orthopaedic Surgeons.
The Canadian results support those of a controversial 2002 NEJM study in which two-year outcomes of patients who underwent arthroscopy were similar to those of patients who underwent "sham surgery," in whom an incision was made and debridement simulated but no arthroscopic tools were inserted. Sham surgery is considered one of the most effective ways of determining whether the result of a procedure is related to the procedure itself or to a placebo effect.
Although the Canadian study did not utilize a sham protocol, it did address aspects of the earlier study's methodology that had been criticized. The 2002 study, conducted at the Houston Veterans Affairs Medical Center, used an outcome measure that had not been validated and a study population that was predominantly male.
The Canadian researchers excluded patients who had large meniscal tears, which have been shown to respond well to arthroscopic treatment, in addition to their knee OA. In an accompanying editorial, Robert G. Marx, MD, of the Hospital for Special Surgery in New York City, emphasized that OA is not a contraindication for arthroscopy in patients whose knee pain is more likely to be related to coexisting meniscal pathology than to the OA itself.