Arthroscopic treatment of osteoarthritis of the knee: a prospective randomised, placebo controlled trial.

The reasons why many patients seemingly benefit from arthroscopic treatment of osteoarthritis of the knee remain obscure. The purpose of this pilot study was to determine if a placebo effect might play a role in arthroscopic treatment of this condition. After giving full informed consent, including full knowledge of the possibility and nature of a placebo surgery, five subjects were randomized to a placebo arthroscopy group, three subjects were randomized to an arthroscopic lavage group, and two subjects were randomized to a standard arthroscopic debridement group. The physicians performing the postoperative assessment and the patients remained blinded as to treatment. Patients who received the placebo surgery reported decreased frequency, intensity, and duration of knee pain. They also thought that the procedure was worthwhile and would recommend it to family and friends. Thus, there may be a significant placebo effect for arthroscopic treatment of osteoarthritis of the knee. The small numbers in this preliminary study preclude a valid statistical analysis, and no conclusions can be drawn regarding the superiority of one treatment over another. A larger study is needed to evaluate fully the efficacy of an arthroscopic procedure for this condition and to decide if it is reasonable to expend health care resources for this treatment; the larger study should include a placebo control group.