Osteoarthritis of the Knee – An Introduction

Abstract

Osteoarthritis of the knee is common, and a major cause of disability in older people that is likely to increase over time. Some patients progress rapidly to needing surgery, whereas others will have persistent pain for many years. The aims of conservative treatment are to reduce pain and disability. There is evidence that several non-pharmacological therapies such as exercise, education and weight loss can have an effect in patients with knee pain, though the effect is usually only modest. Ultrasound and short wave diathermy are widely available, but not supported by evidence. Particular preparations of topical treatments are effective, as too is oral paracetamol (acetaminophen). Glucosamine is popular but not all trials have found it to have any effect. Non-steroidal anti-inflammatory drugs (NSAIDs) are effective, though their effect is modest and their longterm value is not established. They are associated with significant adverse events, particularly gastrointestinal haemorrhage, which has a substantial mortality. They are particularly dangerous in the elderly. Cyclooxygenase-2 (COX-2) inhibitors cause fewer gastrointestinal problems but increase the risk of vascular events including myocardial infarction and stroke. Herbal therapies have only sparse evidence in support. Intra-articular injections of steroids may be effective, at least for a short period, but hyaluronan has a longer duration of action. Patients prefer treatments that are safe, and are willing to forgo some effectiveness in favour of safety. In this context, acupuncture is a potentially valuable treatment for OA knee, and the evidence on effectiveness, safety and cost should be considered carefully.