Group-based exercise in water over 1 year can produce significant reduction in pain and improvement in physical function in older adults with lower limb OA, and may be a useful adjunct in the management of hip and/or knee OA. The water-exercise programme produced a favourable cost-benefit outcome, using reduction in WOMAC pain as the measure of benefit. Further research is suggested into other similar public health interventions. Investigation is also needed into how general practice can best be supported to facilitate access to participants for research trials in healthcare, as well as an examination of the infrastructure and workforce capacities for physical activity delivery and the potential extent to which healthcare may be supported in this way. More detailed research is required to develop a better understanding of the types of exercise that will work for the different biomechanical subtypes of knee and hip OA and investigation is needed on access and environmental issues for physical activity programmes for older people, from both a provider and a participant perspective, the societal costs of the different approaches to the management of OA and longer term trends in outcome measures (costs and effects).