New procedure helps use a patient's own cells to repair damaged knees

People who have damaged cartilage in their knees can experience severe pain and disability. But now, they may have a new treatment option, and it's one that uses their own cells.

MACI, or matrix-induced autologous chondrocyte implantation, is the first FDA approved product that actually grows a patient's own cells on scaffolds which are then re-implanted.

"I am back to unlimited walking, unlimited hiking, so my husband and I are getting up to the mountain and getting on some trails, which is really nice," said Karen Mohr.

Mohr was one of the first people in the U.S. to get the MACI procedure last year, after damaging cartilage in her knee during an ultramarathon.

Her doctor, Michael Banffy, is an orthopedic surgeon at Kerlan-Jobe Institute. He first biopsied Mohr's cartilage cells, then sent them to a lab to be grown on a matrix, or membrane, for four weeks. During surgery, he evaluates the size of the damage.

Banffy explained, "Once that's defined, I can take a template, typically some sort of sterile foil, and then from that sterile foil, I can cut the actual membrane to size and then glue that in with something called fibrin glue."

Banffy says the cells start to make themselves at home quickly.

"It's almost immediate. You know, within 60 minutes, there are cells that have already adhered down to the bone below. So it occurs very quickly," Banffy said.

Rehab, on the other hand, will take up to a year. The cartilage cells need time to mature. Trying to do too much too soon could do more damage.

"There's nothing I can do to speed it up. My best chance is to be patient and follow the protocol exactly as described, and then hopefully, when one year comes, my knee is ready." Mohr said.

In fact, she hopes to be running in the mountains again this fall.

Both Mohr and Banffy say having patience during rehab can be the most difficult, but important part of the MACI procedure. It's so new that long-term results aren't available yet, but the NIH reports that short and medium-range improvements in pain and function are good so far.