In this issue of the Annals, Jones et al1 (pp 172) report the results of a randomised clinical trial (RCT) of canes for knee osteoarthritis. Current recommendations on the management of hip and knee osteoarthritis emphasise non-pharmacological interventions, with sticks or canes universally recommended in existing guidelines.2 According to the Osteoarthritis Research Society International (OARSI) recommendations for the management of hip and knee osteoarthritis one of 25 treatment propositions recommended is ‘Walking aids can reduce pain in patients with hip and knee OA. Patients should be given instruction in the optimal use of a cane or crutch in the contralateral hand. Frames or wheeled walkers are often preferable for those with bilateral disease.’3 In the National Institute for Health and Clinical Excellence (NICE) guideline for care and management of osteoarthritis in adults, assistive devices (such as walking sticks) are considered as adjunct treatments.4 While both the OARSI and the NICE recommendations acknowledge the paucity of well-designed clinical trials in this area, there appears to be a high degree of expert consensus that walking aids can reduce pain in patients with hip and knee osteoarthritis. One might then ponder the need for a randomised trial on canes for knee osteoarthritis.

RCT provide the most unbiased evidence about the benefits and harms of medical interventions. However, sometimes when there are clear indications from observational studies that an intervention has a dramatic beneficial effect, a RCT is considered unnecessary and unethical. For example, although the evidence for the effectiveness of joint replacement surgery for severe knee and hip osteoarthritis is based substantially on uncontrolled observational studies and cohort studies in which outcomes have been compared with standard medical care, most people will agree that a RCT comparing surgery with the standard medical care of the present is unethical …