When Is a Meniscus Transplant Not an Option?

knee meniscus anatomy
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Meniscus transplantation, or placing cartilage from a cadaver donor into a patient, has become a possible treatment for patients with a specific pattern of knee pain. The ideal patient is someone who had their meniscus removed, and subsequently begins to develop knee pain. The patient is too young and too active to consider a joint replacement. Yet all the other "usual" treatments (anti-inflammatory medications, physical therapy, Synvisc, cortisone, joint supplements, etc...) just aren't doing the trick.

The questions is, what is a reasonable treatment.

In the last decade, meniscus transplantation has become a reasonable treatment option to be considered for some patients with specific types of knee pain. The problem is, the number of patients for whom a meniscus transplant is a reasonable option is quite small. That said, if you think you may fit the criteria for considering a meniscus transplant, read on....

Meniscus Tears

The meniscus is a complex structure that provides both cushioning and stability to the knee. Without the meniscus present, patients are much more likely to develop accelerated degenerative changes to the knee joint. As this happens, the remaining cartilage that covers the ends of the bone, called the articular cartilage, is worn away, and bone is exposed. 

For this reason, orthopedic surgeons attempt to preserve the meniscus when surgically treating a torn meniscus. During surgery, only the damaged portion of the meniscus is removed, or your surgeon will perform a meniscal repair if possible.

Unfortunately, despite advances in arthroscopy, not all meniscus tears are amenable to repair. In some cases, in order to best treat the damaged meniscus, the entire meniscus must be removed.

Removal of Damaged Meniscus

When the meniscus is removed, the patient is left without much of the joint cushion.

Initially, this tends not to be a problem. But over time, patients often develop pain where the meniscus was removed, and they can go on to develop accelerated arthritis in that part of the knee joint.

The hope of a meniscus transplant is that by restoring the normal joint support and cushioning of the meniscus, the pain will be alleviated and the degenerative changes will slow. It is important to understand, this is the goal of meniscus surgery, and while early studies show cause for optimism, it is not known that a meniscus transplant has any effect on protecting the joint from further degeneration!

When Transplant Is An Option

  • A young to middle-age patient (20-50 years old)
  • Underwent prior meniscectomy (removal of meniscus)
  • Normal or limited damage to the articular cartilage (bone lining) of the joint
  • Symptoms consistent with the absence of a meniscus

Unfortunately, finding a patient who fits these criteria is a difficult task. Many patients have undergone a prior meniscectomy (meniscus removal surgery), and many of these patients have persistent problems related to the removal of the meniscus.

However, most people who become symptomatic because of the absence of a meniscus, already have developed damage to the cartilage that remains in the knee. Patients who have this accelerated degenerative change to their knee joint are not good candidates for meniscus transplant surgery.

When Transplant Is NOT an Option

  • 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 degenerative changes within the joint (early arthritis)
  • You have instability or malalignment of the knee joint
  • You are unwilling to perform the lengthy rehabilitation from meniscus transplant surgery
  • You have unrealistic expectations

Allow me to further explain this last point. Some patients are looking for solutions that surgeons cannot necessarily offer. The goal of a meniscus transplant surgery is to reduce pain associated with normal activities. The goal is not to give the patient a "normal" knee, but rather to make it better. It is possible that patients may not be able to resume competitive athletics despite a successful meniscus transplant. Patients who expect more than reduction of pain may want to consider other options as they may find disappointment with their results.

Sources:

Sekiya JK, Ellingson CI. "Meniscal allograft transplantation"J Am Acad Orthop Surg. 2006 Mar;14(3):164-74.

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