The most frequent indication for knee arthroscopy is degenerative joint disease in middle aged and older patients. Each year, more than 700 000 knee arthroscopies are done in the United States and 150 000 in the United Kingdom.1 Magnetic resonance imaging evidence of meniscal abnormality, osteophytes, cartilage damage, and bone marrow lesions is often present. All these imaging abnormalities are common in the general population and are often asymptomatic.2 The evidence base for arthroscopic surgery is known to be weak, and a pressing need exists for more high quality multicentre randomised controlled trials, systematic reviews, and meta-analyses to inform clinicians and improve care for patients.3 Researchers have already reported that trials of arthroscopic surgery find no benefit over control interventions ranging from exercises to placebo surgery.4

A linked paper by Thorlund and colleagues (doi:10.1136/bmj. h2747) adds substantially to the debate by systematically reviewing all the evidence on the benefits and harms of arthroscopic knee surgery for middle aged and older adults with knee pain and degenerative knee disease.5 The authors report that the small benefit seen after arthroscopic surgery of the knee …