Considering the high prevalence of knee osteoarthritis and the relatively common use of arthroscopy to treat this condition, few well-designed studies have been published on the effectiveness of arthroscopy for treating knee osteoarthritis. The study by Kirkley et al. is a welcome addition to the literature as it addresses many of the criticisms of previous work by using appropriate exclusion criteria, standardizing treatment in the study groups, using well-validated clinical scores, and providing a period of follow-up exceeding 2 years. The authors conclude that although all patients benefited from active treatment for knee osteoarthritis, comprising rehabilitation and optimized medical treatment, the addition of arthroscopic debridement of the knee did not improve outcomes. These results underline the outcome of a previous prospective, randomized trial, which concluded that the placebo effect of performing knee arthroscopy for osteoarthritis accounted for the main therapeutic benefit observed at follow-up.