A cartilage autotransplant is the autologous implantation of chondrocytes, which produce cartilage, in order to treat knee defects. Chondrocytes are isolated from cartilage tissue taken from the patient’s own knee, and then grown in the laboratory before being implanted into the knee 6-8 weeks later. During the implantation procedure, an open incision is made, the chondrocytes are implanted, and a layer of bone-lining tissue is sewn over the area. Implantation can either be performed under general anaesthesia or using a spinal block, a type of regional anaesthesia that numbs the lower back and extremities.
Who is a candidate?
Ideal candidates typically are younger patients (ages 15 to 55) that have defects of the knee joint caused by acute or repetitive trauma and are not overweight or obese. These knee joint defects should result in small areas of cartilage damage, rather than widespread wear of the cartilage. These patients typically have joint pain, swelling, catching or grinding, but do not have enough overall knee damage to justify a total knee replacement. However, patients typically are experiencing significant impairment of quality of life even after extensive nonsurgical treatment.
Who is not a candidate?
Candidates with arthritis are not candidates for cartilage autotransplant, as arthritis is an autoimmune disease that would result in the individual’s immune system attacking the new cartilage that was implanted.
Prior to undertaking cartilage autotransplant, a complete evaluation made first by traditional diagnostic methods should be undertaken. The final decision is typically made by an orthopedic physician with the aid of an arthroscopic examination. Prior to the implantation step in the two-step process, you should inform your orthopedic surgeon of any medications or supplements you take, and comply with certain general surgery procedures such as preoperative blood testing and possible cessation of smoking or use of pain relievers and anti-inflammatory drugs one week prior. You may need to stop taking blood thinner medication (e.g. Warfarin). You will likely be asked to stop eating or drinking the night before the surgery if general anesthesia is needed.
After implantation, avoid weight-bearing on the area of the cartilage implant in order to allow the cells to adhere to the area. Depending on the area of the implant, crutches may be necessary, or motion should be limited altogether. For any major pain or discomfort during the initial recovery period, you will have prescribed pain medication. Motion may be encouraged in some cases in order to stimulate healthy cartilage growth. Overall, weight bearing is usually limited for 6-8 weeks, and gradually increases over time. Supplemental physical therapy will help restore strength and range of motion. Full recovery will take up to 12 months, but light normal activities can resume a few weeks after surgery.
As with any surgery, there are risks of complications related to infection, damage to nerves and blood vessels, bleeding and blood clots, or adverse reactions to anesthesia. The knee joint in some cases becomes stiff and requires a significant arthroscopic procedure to trim scar tissue. Failure of the procedure is also possible, and may cause recurrence of original symptoms or may necessitate more invasive surgery, such as a knee replacement.
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