Some Twin Cities doctors are using stem cells to give relief to people who suffer from chronic pain in their knees. More than one million Americans will have a knee procedure this year to ease chronic pain, but any complications can have a painful cost. One week after minimally invasive surgery, Andrew Gantman's knee is looking good and nearly pain-free. But his orthopaedic surgeon, Dr. Joel Boyd said Andrew has a 90 percent chance of developing arthritis in that knee at some point. "You may have patients who go onto arthritis within two to three years versus patients who go...