Current Topics in Orthopaedics

Redding Physical Orthopedics, California Physical Therapy

Meniscal Allografts

Damage to the meniscal cartilage of knee joints is a common injury in today's active population. Fortunately, in most cases the meniscus is repairable, or only a portion of the meniscus is removed. In the past, however, many patients have undergone total meniscectomy, and in some current meniscal injuries the damage is too extensive to be able to save much of the meniscus.

In cases where the entire medial or lateral meniscus has been removed, post-traumatic arthritis may develop because of abnormal stress and wear to the articular cartilage of the knee. Until recently, orthopedic surgeons had very limited options for such patients, and often the arthritis gradually worsens until a joint replacement is necessary. Today, however, the absent meniscus can be replaced with a cadaver-donated allograft meniscus, and the advancement of the arthritis can potentially be arrested, or at least slowed, to delay or prevent the need for joint replacement.

The Problem

Normal menisci (plural for meniscus) are ring shaped padding cartilages between the femur and the tibia at the knee joint. The act as "shock absorbers" for the knee, and protect the articular cartilage from excessive wear. The articular cartilage lines the end of the bone, and is the cartilage involved in the development of arthritis.

Redding Physical Orthopedics, California Physical Therapy

When a meniscus is removed, excessive stresses occur, and the articular cartilage will eventually wear out. The loss of the meniscus causes a significant increase in stress to the central area of the articular cartilage.

With arthroscopic treatment of meniscus tears, we are generally able to leave at least a portion of the meniscus behind, or even to repair the meniscus and save the entire structure. However, prior to the advent of arthroscopy, many patients had their entire meniscus removed. We now know that this is detrimental to the knee, but at the time, had no other choice in terms of treatment.

Redding Physical Orthopedics, California Physical Therapy

Meniscal allograft reconstruction allows surgeons to replace menisci which have been removed. Menisci are harvested from donors, and preserved by a cryopreservation technique which maintains cell structure, and tissue integrity, yet destroys bacteria and viruses, and reduces immunologic reactivity. This yields a graft tissue which heals well, with little chance of graft rejection, and virtually no chance of disease transmission.

The surgery involves suturing the new meniscus in place, with an anchor of bone to maintain the normal shape of the meniscus. It is a combined arthroscopic and open procedure. The patient is placed into a brace for six weeks after surgery, and is not allowed to return to running until approximately four months after surgery.

Redding Physical Orthopedics, California Physical Therapy

Results are excellent in terms of pain relief, and long term improvement in function, with approximately 80-90% success rate in most studies. Potential complications include tearing of the graft, loss of graft due to rejection or failure to heal, stiffness, infection, and continued knee pain. The complication rate is low in most studies, and overall the procedure holds much promise for solving a difficult problem in orthopedics.