Knee replacement is one of the commonest surgical procedures performed in older adults, and its incidence is increasing rapidly. It is the only curative procedure for knee osteoarthritis, and it has excellent outcomes overall in terms of reoperation, functional outcomes and cost-effectiveness. However, a significant proportion of patients are dissatisfied after knee replacement surgery and there is a growing body of research into predictors of poor outcome and dissatisfaction.In this review, we discuss the place of total knee replacement (TKR) in the management of osteoarthritis, together with operative and non-operative alternatives to TKR. We discuss the different ways in which outcome can be measured, and the influence of patient and surgical factors on the success or failure of knee replacement surgery.