The knee

Chronic knee pain is common at all ages, particularly in the elderly, among whom it has its greatest impact. Chronic knee pain is often ascribed to os teoarthritis in adults and to chondromalacia patellae in children and adole scents. Pathological findings in both these conditions correlate poorly, ho wever, with the severity of knee pain and disability. Psychometric variable s correlate better with the impact of knee osteoarthritis, suggesting that this disorder has characteristics of a regional pain syndrome. This percept ion may reflect our lack of understanding of the biological mechanisms in t hese disorders. This possibility has been highlighted by the advent of magn etic resonance imaging, and by recent studies of muscle function, reflex qu adriceps inhibition and proprioception in people with knee osteoarthritis. Established risk factors for knee osteoarthritis include increased body wei ght, knee injury and aspects of occupational activity. Recent studies have also suggested a possible role for oestrogens and vitamins C and D in the s econdary prevention of this disorder. The emergence of 'nutraceuticals' suc h as glucosamine as treatments for osteoarthritis has captured the public i magination and merits further study.