Meniscal Transplant Surgery
The goal of meniscal transplant surgery is to replace the meniscus cushion before the articular cartilage is damaged. The donor cartilage supports and stabilizes the knee joint. This relieves knee pain. The hope is that the transplant will also delay the development of arthritis, but long-term results are not yet available.
Healthy cartilage tissue is taken from a cadaver (human donor) and frozen. This tissue is called an allograft. It is sized, tested, and stored. Correct sizing is one of the most important factors in the success of the transplant. Later, the allograft will be matched by size to a candidate for the procedure.
A screening process is done before selecting a possible donor. Someone who knows the donor well is interviewed to help identify risk factors that would prevent the use of the donor tissue.
Once selected, the donor tissue undergoes many tests. The safety of the tissue is monitored by the American Association of Tissue Banks and the United States Food and Drug Administration. The tissue is tested for viruses like those that cause HIV/AIDS, West Nile virus, hepatitis B and C, as well as for bacteria.
Although meniscal transplants have been performed for more than 20 years, the procedure is still relatively uncommon. This is largely due to the strict criteria patients must meet to be considered for the procedure.
The criteria for meniscal transplant include:
- Younger than 55 years and physically active
- Missing more than half of a meniscus as a result of previous surgery or injury, or a meniscus tear that cannot be repaired
- Persistent activity-related pain
- Knee with stable ligaments and normal alignment
- No or minimal knee arthritis
- Not obese
Meniscal transplant surgery is an arthroscopic procedure. It can be performed on an outpatient basis.
Knee arthroscopy is one of the most commonly performed surgical procedures. In it, a miniature camera is inserted through a small incision. This provides a clear view of the inside of the knee. Dr. Wilson inserts miniature surgical instruments through other small incisions to do the procedure.
Typically, a 2- to 4-inch incision is made in the knee with a few other small "poke" holes. The new meniscal tissue is anchored into the shinbone to stabilize the transplant. More stitches are placed into the meniscal transplant to sew it into place.
The risk of complications from meniscal transplant surgery is very slight. Stiffness, reoperation, and incomplete healing are the most common complications.
Other risks include bleeding, infection, and nerve or blood vessel injury.
The risk of getting an infection from donor tissue is small, but it has happened. You are twice as likely to be struck by lightning (1 in 800,000 chance) than to contract HIV from a meniscal transplant (1 in 1.6 million chance).
Immobilization. You will need to wear a knee brace and use crutches for the first 4 to 6 weeks after surgery. This gives the transplanted tissue time to become firmly attached to the bone.
Physical therapy. Once the initial pain and swelling has settled down, physical therapy can begin. Specific exercises can restore range of motion and strength.
A therapy program focuses first on flexibility. Gentle stretches will improve your range of motion. As healing progresses, strengthening exercises will gradually be added to your program.
Return to daily activities. Most patients are not able to return to work for at least 2 weeks. Many patients with active jobs require 2 to 3 months of rehabilitation before they resume their jobs. Dr. Wilson will discuss with you when it is safe to return to work, as well as any sports activity. Full release is typically given 6 to 12 months after surgery.
The research studies that have been done on meniscal transplants are not perfect. Overall, between 21% and 55% of transplants fail within 10 years. Meniscal transplants on the outside (lateral) part of the knee are more successful than those on the inside (medial) of the knee.