Carticel: Replacing Damaged Knee Joints with Biologic Tissue

It has been over a month since my last post, so I thought that after such a long delay I should create a blockbuster post. The photos alone should mesmerize orthopedic blog readers.

Occasionally as orthopedic surgeons, we are challenged to find a biologic treatment for young patients whom either through disease (osteochondritis dissecans is the most common) or through trauma are left with large (greater than 2x 2 centimeter defects) full thickness articular cartilage defects in the knee (femur) that are best treated by the Carticel procedure (Genzyme Biosurgical). These defects are too large to be treated by micro fracture or OATS procedures.

This treatment requires a minimum of two operative procedures. Surgery number one is an arthroscopy of the knee at which time two or three "tic tac" sized pieces of articular cartilage are harvested from a perimeter, unimportant part of the knee joint. Sometimes concomitant with this arthroscopy other procedures are done (bone grafting or osteotomy, but I will not go into this as it complicates this discussion).

The patient's articular cartilage cells are sent overnight in a refrigerated package to Genzyme Biosurgical. The cells can be stored for 5 years. When the patient is ready for the second procedure to implant the cells, Genzyme is notified. The cells are then grown in culture until millions of cells have be produced. The patients own cells are then placed in 1-3 vials and sent overnight to the hospital to be implanted.

Surgery number two is an open knee operation in which: 1. the articular cartilage (joint surface) lesion is trimmed to a circular or oval shape 2. A periosteal patch(cellophane like tissue covering bone) is harvested from the tibia, cut to size and sewn into place over the articular defect with very fine (about the diameter of human hair) absorbable sutures 3. The periosteal patch is sealed with tissue glue, tested to confirm there are no leaks and then the patients own cells which are in a semi liquid form are injected under the patch into the defect and a final suture and tissue glue is applied.

After the second operation the patient is hospitalized a night or two. These patients have a very regimented post operative rehabilitation protocol and limited activities for 6-12 months while the cells heal and replace the damaged joint surface with new cells that are similar to the cells nature initially produced. However, after healing is complete they can return to activities, with or without limitations depending on the overall health of the knee, the number and size of the defects.

This procedure is limited to patients aged 15 to 45 (maybe 50) and can not be used to treat osteoarthritis.

Enjoy the photos. Photo one: articular lesion trimmed and ready for the periosteal patch. Photo two: periosteal patch sewn into place. Photo three: Patients own cells in place under the patch sealed with tissue glue. This is a lesion of the medial femoral condyle and the underlying disease is osteochondritis dissecans.