Meniscus surgery

Why is it important to preserve the knee meniscus?

In the not too distant past, a damaged meniscus was simply removed (meniscectomy) because doctors thought it to be only a remnant of tissue from early embryo development.

Eventually they came to appreciate that removing the meniscus led to a high incidence of early knee arthritis.

Now it is appreciated that the meniscus is really important as a shock absorber and stabiliser of the joint, and surgery is focused on preserving as much of its structure and function as possible. When damaged beyond repair or reconstruction, meniscectomy may still be necessary but there still remains the possibility of a meniscus transplant for preserving function.

In addition, realigning the bones via osteotomy may alter the forces going through the joint to minimise pressure on the damaged side.

Back to top

Why has meniscus trimming developed a bad reputation?

It has been common in the past for knee surgeons performing arthroscopy to 'trim' frayed edges of a damaged meniscus ('arthroscopic partial meniscectomy') in an attempt to prevent or slow further destruction.

Studies have shown that, at least in the older population group with degenerative rather than traumatic meniscus damage, there is little benefit and may actually be some harm from interfering, and with a slightly more rapid onset of osteoarthritis. This has prejudiced health insurance companies from paying for such procedures in patients over 65.

Back to top

What are the consequences of removing a meniscus?

Injury may cause a tear in the body of the meniscus, disrupting its fibres and damaging its ability to function as a spacer, shock absorber and stabiliser of the joint. But removal of the damaged meniscus brings its own set of problems.

The changed forces may damage the delicate white articular cartilage covering and protecting the ends of both femur and tibia bone, and the cartilage itself may break down and the bone put under stress. As the bone tries to repair the problem its healing systems may become disturbed and cysts and spurs may form instead. The collateral ligaments on the other side may become stretched and allow an outward thrust of the joint with each weight-bearing step. Eventually the articular cartilage and bone on the 'good' side become damaged as a consequence.

If damaged meniscus tissue needs to be removed, then today's surgeon will try to remove as little as necessary (meniscal trim), preserving where possible the very important outer rim which does most of the work protecting the vulnerable joint cartilage which it usually cushions. The younger patient may be offered a realignment osteotomy, to try and shift weight-bearing over to the good side, and if the meniscus has to be removed then a transplant may be offered.

...factors that should be taken into consideration for meniscectomy include the repairability of the meniscus and the influence of combined ligament injury or articular cartilage damage. In addition, patient's age, health status, life style, level of sports activities, and the location and pattern of the meniscal tear.

Hwa-Jae Jeong et al

Back to top

Meniscal repair

Sometimes in an incompetent meniscus the meniscus itself may be intact but the connections to the tibia may be damaged, such as in a meniscal root tear.

Longitudinal tears through the meniscus tissue offer an opportunity for stitches (sutures) to pull the damaged edges together until fibrous healing has taken place.

Back to top

Meniscus surgery

Why is it important to preserve the knee meniscus?

In the not too distant past, a damaged meniscus was simply removed (meniscectomy) because doctors thought it to be only a remnant of tissue from early embryo development.

Why has meniscus trimming developed a bad reputation?

It has been common in the past for knee surgeons performing arthroscopy to 'trim' frayed edges of a damaged meniscus ('arthroscopic partial meniscectomy') in an attempt to prevent or slow further destruction.

What are the consequences of removing a meniscus?

Injury may cause a tear in the body of the meniscus, disrupting its fibres and damaging its ability to function as a spacer, shock absorber and stabiliser of the joint. But removal of the damaged meniscus brings its own set of problems.

Meniscal repair

Sometimes in an incompetent meniscus the meniscus itself may be intact but the connections to the tibia may be damaged, such as in a meniscal root tear.

Other relevant links on KNEEguru