Meniscus Allograft Transplantation

Meniscus Anatomy

The meniscus is a C-shaped cartilage ring that acts like a cushion between the shinbone and the thighbone. Each of your knees has two menisci - one on the inside (medial aspect) and the other on the outside (lateral aspect) of your knee. Apart from the cushioning effect, the menisci also provide stability to the knee.

Meniscal Tear

A meniscal tear is a common knee injury that usually occurs secondary to trauma and is common in athletes. A meniscal tear may also occur in the elderly due to degenerative changes in the knee. A damaged meniscus predisposes you to persistent pain, swelling, and arthritis.

Diagnosis of Meniscal Tears

A diagnosis of meniscal tear as a cause of knee pain comprises of a medical history along with the presenting symptoms followed by a physical examination of the knee. Dr. Patel may also order a few imaging studies such as an X-ray and MRI scan of the knee to rule out other possible diagnoses. X-rays help to identify degenerative changes such as osteoarthritis which can cause knee pain. MRIs help to visualize the menisci and assess the location and severity of the injury.

Treatment of a Meniscal Tear

Treatment of a meniscal tear depends on its type, severity, and location of the tear. Non-surgical options for the treatment of meniscal tears may include ice application, rest, elastic bandage, elevation, and physical therapy. However, a badly damaged meniscus may have to be removed. Knee replacement may be an option to consider in older individuals. However, meniscal transplantation can be an alternative option in younger patients.

What is Meniscal Allograft Transplantation?

Meniscal transplantation is a surgical procedure to replace the entire damaged meniscus of the knee with an entire healthy donor meniscus.

Indications and Contraindications of Meniscal Allograft Transplantation

The eligibility criteria for a meniscal transplantation include:

  • Young to middle aged patients (below 50 years of age)
  • Patients with stable, well-aligned knees
  • Patients with intact or minimally damaged articular cartilage in the joint
  • Patients who have already undergone a prior meniscectomy (removal of meniscus)
  • Patients who complain of persistent activity-related pain

Meniscal transplantation is not recommended for patients with severe arthritic changes within the joint.

Meniscal Allograft Transplantation Procedure

The goal of a meniscal transplant surgery is to reduce pain and prevent arthritic changes. The surgery is performed under general anesthesia on an outpatient basis. The procedure is usually performed with the help of an arthroscope (a fibre optic instrument), which is used to visualize the internal structures of the knee. A tiny camera is attached to one end of the arthroscope which transmits the internal images of the knee to a TV monitor. The arthroscope allows the surgeon to evaluate the entire knee joint including the cartilage, ligaments and the joint lining.

The meniscus cartilage used for transplantation is derived from a human cadaver donor (allograft). The healthy donor meniscus is size and age-matched for the recipient; on the day of the surgery it is preoperatively fine-tuned to fit the patient’s knee.

For the surgery, a surgical incision is made over the front of the knee in the area of the meniscus void. Typically, the majority of the meniscus was previously removed, and thus, the remainder is resected and the site is prepared to receive the new meniscal implant. The new meniscus is implanted at the proper site under arthroscopic guidance. Typically, there is some amount of bone still attached to the meniscus roots which are then secured in sockets or troughs. The new meniscus is then sutured to the surrounding capsule, for which an additional small incision is required. Interference screws, buttons and sutures are used to secure the meniscus in place.

Depending on the severity and nature of the damage, additional procedures such as ligament or cartilage repair may also be performed along with the meniscal transplant.

Post-Operative Care for Meniscal Allograft Transplantation

Following the surgery, you will be advised to wear a knee brace to support and protect the knee for the first 1 to 6 weeks. You will be required to use crutches after the surgery, to avoid any pressure or stress over the operated knee. You can start moving soon after the surgery to prevent knee stiffness. Pain relieving medications will be prescribed to control pain. A physical therapy program will help to restore the range of motion and strength of your knee. You may be able to resume work after a few weeks or a few months, depending on the nature of your work. It may take 6 to 12 months for you to return to playing sports.

Risks and Complications of Meniscal Allograft Transplantation

Possible complications associated with meniscus transplantation include:

  • Stiffness of the knee
  • Persistent pain
  • Infection
  • Bleeding
  • Nerve injury
  • Tear of the new meniscus
  • Incomplete healing
  • Transplant dysfunction
  • Small risk of disease transmission from the transplant
  • Weakness of the knee