The Houston Chronicle takes a look at work to regenerate cartilage, in the knee in this case: "Doctors are testing new ways to spur cartilage to regrow in damaged knees, from implanted 'cartilage plugs' to injections of bone-marrow stem cells. ... Knees are the joint most likely to go bad, and the cartilage that cushions them has only a limited natural ability to repair itself. ... new options are being tried first in people who injured their knees and thus need small amounts of cartilage to regrow. But if they truly work, the techniques one day might offer hope for arthritis sufferers, too, whose cartilage over time erodes. Most eagerly anticipated: the first clinical trial using stem cells from donated bone marrow to try to regenerate the knee's shock absorber, a cartilage pad called the meniscus."