CARTILAGE RESTORATION SURGERY – AUTOLOGOUS CHONDROCYTE IMPLANTATION (ACI)
The ends of the femur, tibia, and undersurface of the patella (kneecap), the knee bones, are capped with a smooth surface, which is called articular cartilage. Cartilage protects the ends of bone; it can withstand a significant amount of impact and is significantly smoother than ice, which allows smooth motion in the knee joint. An articular cartilage injury (or “chondral” injury), may occur following a twisting injury to the knee, a direct blow to the knee, or wear and tear as a one ages. Some patients with cartilage injuries can be treated with a combination of activity modification and other non-surgical options, such as a focused physical therapy program. Other patients with persistent symptoms or larger defects may require surgery.
One treatment option for an isolated cartilage injury is autologous chondrocyte implantation (ACI), a two-stage technique. During the first stage, Dr. Keller uses a surgical camera (arthroscope) to view the damaged area of cartilage in the knee and removes a small piece of healthy cartilage from another area in the knee. The healthy piece of cartilage is then sent to a laboratory and grows into millions of healthy cartilage cells. The cartilage cells are then combined with a natural scaffold (collagen membrane) to create the final graft. The graft is then stored in a way that preserves the health of the cartilage cells. In the second surgical stage, Dr. Keller sizes the graft appropriately and then places the graft into the cartilage defect in the knee, similar to filling a pothole. The graft is sealed with fibrin glue.
Following surgery, patients are placed in a hinged brace that is locked straight. Dr. Keller recommends no weight-bearing for 4-6 weeks in the brace. When the patient is sitting or lying down, Dr. Keller encourages knee range of motion exercises with the brace removed. Dr. Keller also recommends intermittent icing and straight leg raises to strengthen the quadriceps muscles. Dr. Keller recommends starting physical therapy one week after surgery. Physical therapy focuses on reducing swelling in the knee, restoring full range of motion, and eventually, restoring strength to the knee. Most patients can start full weight bearing on the affected leg 6-12 weeks after surgery, depending on the location of the defect. Most patients start cutting activities and sporting activity approximately 4-6 months after surgery.