It hurts in my hips. There is a crash in the cross. Your knee chafes every time you go down the stairs. And in general you feel quite stiff. You think to yourself that such little problems are part of getting older. And it’s also true that the body wears out. Osteoarthritis, a degenerative joint disease in which the layer of cartilage between the joint surfaces breaks down, is the most common joint disease worldwide, with around 595 million people affected – and the trend is rising rapidly.