The meniscus is a complex structure that provides both cushioning and stability to the knee. If the meniscus is damaged (i.e., torn), orthopedic surgeons attempt to repair it through surgery. Unfortunately, despite advances in arthroscopy, that is not always possible.

Reasons for a Meniscus Transplant

When the meniscus is removed, you’re left without much cushioning in the joint. Initially, this tends not to be a problem. Over time, osteoarthritis may develop in the knee joint, which may or may not be painful. The use of donor tissue in a meniscus transplant can provide a chance at less pain. In younger patients who develop pain, a meniscal transplant may be an option to try to decrease symptoms and delay the progression of osteoarthritis.

Meniscus transplants are typically done on individuals who:

  • Already had their meniscus removed, but subsequently develop knee pain
  • Are too young and too active to be considered for a joint replacement
  • Have tried other treatments such as anti-inflammatory medications, physical therapy, cortisone, and joint supplements without pain resolution

You’re a good candidate for a meniscus transplant if the following apply to you:

The goal of a meniscus transplant surgery is to reduce pain associated with normal activities. The goal is not to give you a “normal” knee, but rather to make it better.

  • You’re under age 55You have undergone a prior meniscectomy (removal of meniscus) and have none or less than half of your meniscus leftYou have normal or limited damage to the articular cartilage (bone lining) of the jointYou have pain or instability in your kneeYour symptoms are consistent with the absence of a meniscusYou’re prepared for a difficult recovery

Who Is Not a Good Candidate?

Patients who have undergone a meniscectomy and have persistent symptoms related to the removal of the meniscus have probably already developed damage to the cartilage that remains in the knee. People who have this accelerated degenerative change in their knee joint are not good candidates for meniscus transplant surgery.

Other reasons why a meniscus transplant won’t work for you include:

  • You still have a significant portion of the meniscus remaining (this procedure is only for patients who had the bulk of the meniscus removed)You have instability or malalignment of the knee joint.You’re obese.You’re unwilling to perform the lengthy rehabilitation from meniscus transplant surgery.

Another important thing to consider is your expectations. Some patients are looking for solutions that surgeons cannot necessarily offer.

It’s possible that you may not be able to resume competitive athletics despite a successful meniscus transplant. If you’re expecting more than the reduction of pain, you may want to consider other options as you may be disappointed in the results of this surgery.

Types of Donors

The meniscus used for your transplant will come from a cadaver. When the transplanted tissue comes from another person, it is called an allograft transplant.

Donor menisci may be fresh, frozen, or cryopreserved, with frozen being the most common option. These tissues are stored in a tissue bank. Fresh menisci are only viable for 14 days after being removed from a cadaver.

The meniscus used for your transplant must also be the appropriate size for your body. Before your surgery, the donated meniscus will be screened for any signs of infection.

Donor Recipient Selection Process

With organ transplants, recipients are typically put on a waiting list and may have to wait for months or years for the needed organ to become available. Certain patients may have priority over others, or be lower on the list, depending on specific factors, such as age, degree of illness, or a substance abuse disorder.

Because menisci are readily available and do not have to be transplanted within a number of hours after being removed from the donor, there is no need for a waiting list. If you meet the basic requirements for a meniscus transplant, you will likely have no problem receiving the meniscus itself.

Before Surgery

Your healthcare provider will ask you which medications you take and may want you to stop taking certain ones, such as blood thinners and anti-inflammatory medications prior to your surgery. You’ll also need to stop eating and drinking after midnight on the day of your procedure. Additional imaging tests such as magnetic resonance imaging (MRIs) or X-rays may be necessary as well.

Make sure you have arrangements in place for going home and recovering after the surgery. For example, someone will need to drive you home. You may be able to go home the day of the procedure, but it’s possible you’ll need to stay in the hospital for a day or two.

You will be using crutches for several weeks and will most likely need help at home for a while.

Surgical Process

An orthopedic surgeon will perform the surgery arthroscopically, which will take a couple of hours. Here is what you can expect:

  • An anesthesiologist will administer medication to put you to sleep during the operation. In some cases, you may receive spinal anesthesia and a tranquilizer instead of general anesthesia. If you have the latter, you may have a tube inserted in your throat to help you breathe. Your vital signs will be monitored during the operation.After cleaning the affected area, your surgeon will make a small incision through the skin and muscle of your knee, and then insert a very small camera through this incision, using it to help guide the surgery.Your surgeon will remove any remaining parts of your meniscus. Next, they will surgically sew the donated meniscus into the joint space, possibly using screws or other medical devices to hold it in place.The surgeon will then close the layers of skin and muscle around your knee.

Once the surgery is complete, you will be taken to the recovery room where you’ll be monitored as the anesthesia wears off.

Complications 

Meniscal transplant surgery is generally safe, though there are always risks. In addition to the risks inherent in any surgical procedure, possible complications include:

  • Stiffness of the joint after surgeryIncomplete healing, possibly requiring another surgeryExcess bleedingInfectionDamage to nearby nervesGetting an infection from the donated tissue (extremely rare)

After Surgery

Unlike with other tissue transplantations, there is little risk that a meniscal graft will be rejected; therefore, anti-rejection medications are not necessary. You will be given a prescription for painkillers, however.

Once you are cleared to go home, you will begin your recovery and rehabilitation. Initially, you may have some fluid draining from your incision, which is normal.

You will need to wear a knee brace and use crutches for a few weeks. Your healthcare provider will give you instructions about how you can move your knee while you recover. To help you maintain strength and range of motion during the recovery period, you will likely need physical therapy.

Let your healthcare provider know right away if you see an increase in redness, swelling, or draining from the surgical site, or if you have a high fever, chills, or severe pain.

Your healthcare team will advise you as to when you can begin to resume daily activities and exercise, which may take several months. In general, strenuous weight-bearing activities are not recommended in order to preserve the transplanted graft. If you previously engaged in high-impact exercise or competitive sports, you may have to avoid them moving forward and find alternative activities (such as swimming) that put less stress on your knee.

Prognosis

The goal of a meniscus transplant is to restore the normal joint support and cushioning of the meniscus so that pain will be alleviated. While the procedure does help with this, studies show that meniscus transplants don’t slow down or prevent osteoarthritis in the knee; more surgeries and/or a knee replacement will likely eventually be needed in such cases. The overall 10-year success rate for meniscal transplantation is approximately 70%.