Meniscal Injury
Ross Hauser, M.D.

The menisci consist of semilunar fibrocartilage, partly filling the space between the femoral and tibial bones. Four principal functions are ascribed to the menisci:

1. To spread a thin film of synovial fluid which provides nutrition to the articular cartilage

2. To act as shock absorbers

3. To increase the stability of the knee joint

4. To aid in the complex rotatory mechanics of the knee joint.

Meniscus injuries often occur in combination with ligament injuries, particularly when the medial meniscus is involved. This is partly because the medial meniscus is attached to the medial collateral ligament. Injury to the medial meniscus is about five times more common than injury to the lateral meniscus.(1)

Meniscus Surgery
By knowing the function of the meniscus, it is possible to predict what will happen when meniscal tissue is shaved or removed. Since it provides some of the nutrition to the articular cartilage, its removal will aid in the demise of the cartilage. If the cartilage is damaged, then the pressures on the bone will be too great and arthritis will soon follow. This is not the only reason why articular cartilage damage is sure to follow after meniscectomy. The removal of the menisci allows too much pressure to be put on the articular cartilage, thus lessening the shock absorption. This is why cartilage damage and proliferative arthritis must be the end result of meniscal removal. No other option is available. If the surgeon removes the meniscus, arthritis is the end result. If that were not enough, the menisci aid in the stability of the knee. If they are removed, the knee is left with too much motion and becomes unstable. This also increases the likelihood of articular cartilage damage and subsequent arthritis.

Arthroscopic shaving and removal of the meniscus would therefore be expected to result in the progression of arthritis in the knee.

Study Shows Increased Contact Stress Pressure after Meniscectomy
There have been numerous studies showing that the contact stress pressure on the articular cartilage significantly increases after meniscal removal.(2,3)

One such study showed that after partial meniscectomy, the contact stress pressures increased by 110 percent and after total meniscectomy they increased 200 percent. Their conclusion was expected. "The contact stresses increased in proportion to the amount of meniscus removed." (4)

Other studies have shown even greater increases in pressure, causing from a 450 to 600 percent (six times) increase in pressure on the tibia bone and articular cartilage when the meniscus is removed. (5,6)

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