Introduction

Osteoarthritis is the most prevalent form of arthritis, with an associated risk of mobility disability (defined as needing help walking or climbing stairs) for those with affected knees being greater than that due to any other medical condition in people aged3 65.^w1 The societal burden (both in terms of personal suffering and use of health resources) is expected to increase with the increasing prevalence of obesity and the ageing of the community.

Osteoarthritis is a multifactorial process in which mechanical factors have a central role and is characterised by changes in structure and function of the whole joint.1 There is no cure, and current therapeutic strategies are primarily aimed at reducing pain and improving joint function. We searched Medline for relevant articles (1966 to January 2006) and the Cochrane library (to first quarter of 2006) and consulted experts in rheumatology to produce a narrative review with an update on management for primary care doctors. We concentrated on osteoarthritis of the knee as this is associated with the greatest public health burden.

What is osteoarthritis?

Osteoarthritis is the clinical and pathological outcome of a range of disorders that results in structural and functional failure of synovial joints.2 Traditionally, it has been considered a disease of articular cartilage. The current concept holds that osteoarthritis involves the entire joint organ, including the subchondral bone, menisci, ligaments, periarticular muscle, capsule, and synovium (fig 1).

Epidemiology of osteoarthritis

The reported prevalence of osteoarthritis varies according to the method used to evaluate it. In most epidemiological studies it is commonly assessed by radiography. Marked osteoarthritic damage must be present, however, to detect characteristic changes with plain radiographs, and they are therefore not sensitive diagnostic tests. About 6% of adults age 3 30 have frequent knee pain and radiographic osteoarthritis.

Osteoarthritis …