tivated for 6
weeks until
they
increase in
number.
Thus revivi-
fied, they're
injected
into the
joint
beneath a
patch sewn in as a scaffold during open surgery. In the best-case sce-
nario, they kick-start the growth of new cartilage and fill in the defect.
Because stem cells, like chondrocytes, originate from the patient's own
tissue, the risk of rejection is low. But the advantage of stem cell
implantation over ACI is that it doesn't require an initial harvest from
the damaged joint.
There's a catch, though. At present, stem cells can't be "super-
charged" for most knee repairs the way that chondrocytes can. While
stem cells can be harvested from the patient and then injected directly
into the joint, the amount that are put to work varies from case to
case, which may affect the results. "We could concentrate them if we
manipulate them in the lab, which would grow and multiply the num-
ber of cells," says Dr. Dodson. "But in the U.S., stem cells currently
cannot be used when they've been manipulated in any way. The FDA
hasn't approved that as safe. If we're going to manipulate, it has to be
in the context of a trial."
Animal studies are experimenting with different methods of deliver-
ing stem cells to the diseased joint. It's an important consideration,
says Dr. Dodson. "A gel or a scaffold is needed to hold the cells in the
F E B R U A R Y 2 0 1 6 • O U T PA T I E N TS U R G E R Y. N E T • 5 1
• QUALITY CHECK A custom-made knee implant is inspected and compared to its manufacturing specifications.
ConforMIS
