Acute calcific synovitis of the knee.

Degenerative osteoarthritis is a cause of joint pain common in the elderly. The knee joint is often affected and minor trauma may produce an exacerbation of symptoms. In a proportion of such patients painful symptoms are accompanied by synovitis and swelling of the joint. A clinical syndrome of acute synovitis of large joints, occurring in elderly persons, has been described by McCarty, Kohn and Faires (1962), who concluded that the synovitis was caused by crystal irritation of the synovia. This paper reports five patients who, it is thought, suffered acute inflammation of the knee induced by calcium irritation. A simple approach to diagnosis and treatment is suggested.