"Mimicking Human Cartilage to Repair a Knee"

NY Times
August 16, 2009

By ANNE EISENBERG

One way for surgeons to repair injured knees is to take cartilage and bone from another part of the knee and transplant it in the damaged area.

Now companies are developing potentially simpler knee patches: small, off-the-shelf plugs engineered to mimic the composition of human bone and cartilage.

These ready-made cylinders can be inserted in an arthroscopic procedure; they are often used after a sports injury. They are known as osteochondral scaffolds, because they support new bone and cartilage as it grows.

Orthomimetics, a company in Cambridge, England, has developed a scaffold approved for use in Europe that resulted from a collaboration between faculty members at the Massachusetts Institute of Technology and the University of Cambridge.

The scaffold provides a temporary, engineered matrix when inserted into a drilled hole, said Lorna Gibson, a professor of materials science and engineering at M.I.T. and one of the inventors of the device. Stem cells from the bone marrow that can form bone or cartilage impregnate the pores of the cylinder.

“The scaffold guides the tissue formation of bone on one side and cartilage on the other,” Dr. Gibson said.

The scaffold disappears in about six months. “Over time the cells that attach to the scaffold produce enzymes that dissolve it,” Dr. Gibson said. At the same time, the cells are putting down their own matrix.

Dr. Constance R. Chu, director of the Cartilage Restoration Center at the University of Pittsburgh and the Albert Ferguson associate professor of orthopedic surgery and bioengineering, said that there were potential benefits to using the cylinders to help repair cartilage that protects bones in the knee joint from rubbing against one another.

“Surgeons can do effective repairs by borrowing bone and cartilage from another part of the knee” that is less weight-bearing, Dr. Chu said. “But people don’t have a lot of extra cartilage — if any — to go around.”

Dr. Chu has herself worked on creating such devices. “The thinking has always been that the scaffold will support and guide the repair,” she said. “That’s why people will spend years to make something like this.”

For the full story, please go to:
http://www.nytimes.com/2009/08/16/business/16novelties.html?hpw


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