Arthritis breakthrough: 3-D printer and stem-cell solution used to create cartilage

Her foot pain began 15 years ago, leading to a 2002 diagnosis of osteoarthritis, which left her limping and unable to walk for extended periods of time. And it progressively worsened.

In time, Deborah Cole Thomas, 60, of the US state of Pennsylvania, would undergo operations to fuse joints in both feet along with a left-ankle replacement, all from the wear-and-tear form of arthritis. She endured shoulder pain and more recent problems with right-knee pain, which she likens to being stabbed with a knife. Round-the-clock pain medication is a must.

"I try not to let it affect me," Thomas said, noting that her husband, Llewellyn, 82, has had both arthritic knees replaced. "It drives me to keep moving. I watched my mom give up, and her hands became so crippled she had to be fed."

Thomas, now retired, worked as a computer engineer, spending hours at a desk that made her "feel like the Tin Man in The Wizard of Oz". She'd stand and struggle to flex stiffened joints.

In coming years, she faces further operations, including knee replacement. But she's still walking, with a goal of 10,000 steps a day and an average of 7,000.

She can't run and isn't allowed to jump. Doctor's orders. But she works around the limitations. "There's always something I can do just to keep moving."