Stiff knees, aching hips and the slow grind of chronic joint pain are often accepted as an unavoidable part of getting older. But while osteoarthritis is the world's most common joint disease, experts say the way we treat and prevent it is badly out of step with the evidence. The best medicine isn't found in a pill bottle or an operating theatre – it's movement. Yet across countries and health systems, too few patients are being guided toward the one therapy proven to protect their joints and