Save Your Knees

Bum knees have sidelined professional and amateur athletes alike, and until recently, the diagnosis was I.D.K., an acronym for internal knee derangement that specialists joked actually stood for ""I Don't Know.'' The prognosis has improved somewhat, and orthopedic surgeon Fox and veteran medical writer McGuire offer a definitive book on the knee that will encourage a wide audiencefrom athletes to arthritics. A delightful bedside manner is enhanced by their gift for visualizing difficult images in easy-to-understand terms (the anatomy lesson describes the knee joint as ``two giant bones propped on top of one another, held together by the anatomical equivalent of rubber bands''). Save Your Knees explains how the knee works, why it gets hurt, how to self-diagnose problems and when and when not to worry about them, and how to find reliefin surgery, exercise therapy, properly fitting shoes and the like. The book discusses questions a patient should ask a physician, as well as pain pills and potions. There are a sport-by-sport breakdown on how to prevent knee injury and a section on exercises that can be performed at home. (May)