One of the most exciting advances in the treatment of knee injuries is the ability to treat damage to the articular cartilage (surface of the joint). Dr Halbrecht was one of the first surgeons in the United States to perform the technique of chondrocyte implantation. With this method, cartilage cells are taken from the injured knee and cloned in the laboratory. They are then reimplanted back into the joint to regrow cartilage on the damaged surface. This technique was initiated in Sweden and has been available in the United States since 1995. FDA approval was officially obtained in September of 1997.
Results for Chondrocyte Implantation
As of 2003, several thousand patients have been treated worldwide with chondrocyte implantation. Current results indicate that patients can expect a 90% chance of successful treatment for isolated articular cartilage injuries of the femur.
ACI is indicated for the younger patient with an isolated articular cartilage injury to the surface of the femur in the knee joint. Recommended age range is 16-55.
Cartilage tissue is removed arthroscopically from the injured knee and sent to a special laboratory where the cells are removed and cloned using specialized cell culturing techniques. The initial procedure to remove the cells is performed under local anesthesia and can be performed in the office. The cells are then returned to the surgeon for reimplantation 4 weeks later. Implantation of the cells is performed through an incision to expose the joint and to sew in a patch of tissue to cover the joint defect. The patch is taken from the lining of the adjacent bone. The cartilage cells are then implanted underneath the patch and the patch is sealed using a “glue” made from the patients own blood serum.
Patients are placed into a passive motion machine for 2 weeks. Quadriceps contractions and leg raises are begun immediately. Weight bearing is not allowed for 6 weeks, in order to protect the cell implant. After 6 weeks, weight bearing and a progressive strengthening and functional exercise program is begun. Return to sports is delayed for 6 months to one year, to allow maturation of the cartilage.
We are currently collecting clinical data on all patients and are performing second look arthroscopies on those that are agreeable. To date, all the implantations have taken, and there have been no technical failures. Clinical results so far are in the 80-90% success range for good to excellent relief of symptoms. Additional studies are being performed to assess the physiological results. These include the use of bone scans and specialized MRI spectroscopy techniques. This data collection is ongoing and will require 3-5 years before statistically significant data will be available.