Note the large hole in the cartilage

Cartilage defects or holes in the cartilage on the end of your bones, can herald the onset of osteoarthritis.  Cartilage is a firm,  smooth white substance found on the ends of our bones.  When we finish growing we have a rather thick layer of it on both sides of the knee joint.  Trauma, sport injuries and degeneration can cause defects or holes in the cartilage surface of the knee.  If you are missing cartilage because of an injury, the remaining cartilage is subject to an increase in stress which can lead to osteoarthritis.

 Repairing holes in the cartilage, or cartilage defects can be challenging.  There is little consensus on which technique is best.  The latest technique available to treat cartilage defects is the DeNovo Cartilage Repair Technique, and the early results are promising.

Prior to DeNovo, the options available to us included procedures where we made small holes into the area where the bone marrow resides.  The goal of this procedure was to get the bone marrow cells to populate the hole in the cartilage and grow into a new cartilage surface.  Although somewhat successful, this “microfracture ” procedure did not produce “normal” cartilage, and the results tend to degrade with time.

Prior to the approval of the DeNovo cartilage repair process we were also able totake pieces of cartilage from a cadaver and transplant it into the defect in your knee.  Although this procedure works well for many cartilage defects, the issue is the availability of fresh cartilage grafts, and the size of the cartilage defect that we are able to treat.

One last technique available to us is called the Carticel procedure.  This technique involves two operations.  One to harvest cartilage cells from your knee, and a second procedure to re-implant those cells a few months later after they had been grown – amplified in a laboratory at Genzyme.

The DeNovo process uses cartilage tissue from organ donors under the age of 13.  The reason why the age of the donor is important is because children possess incredible healing and regenerative potential in comparison to adults.  In addition, the cartilage cells in children are far more dense. This means there are many more cells per graft then if we used cartilage cells from a mature adult.  These young cartilage cells also lack certain proteins, so there is no risk of rejection.

During the cartilage repair process, an open incision is made in the front of the knee to expose or reveal the defect in the cartilage.  The defect is prepared, the cartilage cells are spread within the defect and the cells are kept in place with a special biological glue- called fibrin glue.  The incision is closed, and the body hopefully takes care of the rest. Over the next few months, the cartilage cells should divide, grow and produce a substance we the a matrix… It is the matrix that produces the dense, smooth surface we see when looking at the cartilage.
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