ABSTRACT
Osteoarthritis (OA) is the most common form of joint disease throughout the world. OA has no single cause; rather, it is due to a variable combination of both systemic predisposition and local biomechanical risk factors affecting different individuals and different joint sites, which explains its heterogeneity. Changes related to the female menopause appear to be particularly important, as knee OA prevalence in women rises sharply after the menopause, and inflammatory OA of the hands often starts during the menopause. The differences in shape of hips in Chinese from that in Caucasians may explain the low prevalence of hip OA in Chinese people. Natural history and physiological imaging studies suggest that it goes through periods of activity and quiescence. The natural history, presentation, impact and prognosis are different for each of the major joint sites affected, and management needs to be based on prognosis and impact in particular.
