Body Builders
Tissue engineers like Kristi Anseth and Kyriacos Athanasiou can rebuild you. They have the technology. Well, almost.

For Kristi Anseth, a chemical engineer by training, the path to a new way of thinking about repairing knees and broken bones meandered through the dentist's office.

As a researcher at the Massachusetts Institute of Technology a decade ago, she was ­working with the materials dentists use to fill teeth - alongside an interdisciplinary group of biochemists, clinicians, and others - when an idea struck her. If dentists could fill a cavity with a chemical composite and shine a light on it to cause it to harden,­ why couldn't she engineer something similar for orthopedists dealing with fractures?

"Wouldn't it be neat," she says, "to design something similar to what you do to someone's tooth and use it in a bone defect to get the bone to heal faster? Or in some instances where the bone won't heal at all?"

When she started talking to orthopedic surgeons about her idea, they pointed her in a second direction: cartilage damage in knees. Cartilage doesn't heal itself, and the surgeons were doing more and more total knee replacements (more than 200,000 are performed annually). The body has plenty of cartilage. What if some of the cells from that tissue could be isolated and placed into the knee, and then the cells were encouraged to grow? What if she could use the model of those dental materials and create a sort of scaffolding for cartilage cells?