The meniscus (or, the plural, menisci) is a C-shaped cartilage cushion in the knee joint that helps the joint bear weight, glide and turn. Each knee has two menisci, one on each side that serve as shock absorbers. An orthopaedic surgeon may be able to repair a damaged or torn meniscus. However, a meniscus that is badly damaged or has an extensive tear may have to be removed. Without the menisci, a knee joint can develop persistent pain, swelling and arthritis.
In older patients, a knee joint replacement is an option. But for younger individuals (those under 50-55 years old), there is an alternative to replacing the entire joint. It is called a meniscal transplant and it uses donor tissue to replace the damaged meniscus. This procedure is still relatively uncommon and is not appropriate for all patients. However, patients who qualify can benefit from a meniscal transplant.
Meniscal transplant Q&A
Who is eligible for a meniscal transplant?
A meniscal transplant may be recommended for people who meet the following criteria:
- Physically active and relatively young, under the age of 55
- Missing more than half of the meniscus due to surgery or injury or has a tear that cannot be repaired
- Continues to have activity-related pain in the knee
- Has little or no evidence of arthritis in the knee
Where does the transplanted tissue come from?
As yet, there is no synthetic meniscal tissue. The transplanted tissue comes from human donors. Healthy tissues are frozen and matched by size to the candidate.
How safe is the donor tissue?
The Food and Drug Administration and the American Association of Tissue Banks strictly monitor the safety of donor tissue. Before the transplant is performed, the donor tissue is tested to make sure it is disease-free. Tissues are tested to ensure that they do not have any traces of infectious diseases such as hepatitis or HIV/AIDS. These tests help reduce the risk of contamination. You are twice as likely to be struck by lightning (odds: 1 in 800,000) than to develop HIV from a meniscal transplant (odds: 1 in 1.6 million).
How is the surgery performed?
A meniscal transplant is an outpatient procedure performed using tiny instruments through a small incision (known as arthroscopic or ‘key-hole’ surgery) using a regional aneasthetic. The surgeon will make one small incision in the knee joint, with two or three other ‘nicks’ to help situate the transplant properly. These secondary incisions are so small that they may not even require sutures to close them. The new meniscal tissue is anchored to the tibia, the larger bone in your lower leg.
How long is the recovery period?
For the first 3-4 weeks after surgery, you will have to use crutches and wear a knee brace or immobiliser. This gives the transplanted tissue time to become firmly attached to the bone. If you work in an office and have a mostly sedentary job, you should be able to return to work a week after your surgery. If you have a more active job, you may not be able to resume all your work duties for 2-3 months.
After a month, you can start an exercise therapy program that involves weight-bearing exercises. In many cases, you may be able to return to running after three or four months, and to other recreational activities after five or six months. You should not do certain kinds of activities, such as squatting, bicycling or swimming, for at least six months after surgery.
Are there any complications to the surgery?
There is some risk involved with all surgery. However, the risk of experiencing complications from meniscal transplants is very slight, less than 1%. The two most common problems are infection and tissue rejection.
How successful are meniscal transplants?
Orthopaedic surgeons have been doing meniscal transplants for several years. In 80-90% of cases, they are effective in relieving activity-related pain and swelling. However, long-term results are not yet available. It's also not known whether the transplant will delay or slow the development of arthritis or other degenerative changes in the knee.
A meniscal transplant is not appropriate for every patient; for example, if you already have arthritis in your knee, a meniscal transplant may not help you. But in a select group of patients, meniscal transplants offer significant benefits.