Cartilage tears

Basics


Each knee has two menisci. They are commonly called “the cartilages”. There is one on the inner (medial) side of the knee and one on the outer (lateral) side of the knee. They are C or crescent-shaped and serve to cup the thigh bone (femur) as it sits on the shin bone (tibia) to improve the “fit” of the joint.

The main role of the meniscus is to spread the load being put through the two joint surfaces, thereby protecting the joint surface cartilage. They act as shock absorbers of the knee.
The menisci are important. A torn meniscus does not work properly, instability and early wear in the joint may occur.


Diagnosis and Treatment


Once the diagnosis of a torn cartilage (meniscus) is made you may need an operation to treat it, as it is uncommon for these tears to heal.
Symptoms from small tears can settle down, however, over a few weeks. If symptoms last longer than this, surgery is often needed. Larger tears usually need surgical treatment.
The operation performed will usually be a knee arthroscopy or “key hole” surgery.
Depending on the nature of the cartilage tear, it will either have to be repaired, or trimmed to a smooth edge (a partial meniscectomy).


Partial Meniscectomy


More commonly the torn part has to be removed, a procedure called a “partial meniscectomy”. This is done using special instruments through keyhole incisions at the same time as the knee arthroscopy. The amount of cartilage removed depends on the size of the tear. As little as possible will usually be taken out, trying to leave a smooth stable edge of cartilage behind which will still function as a “shock absorber”.


Meniscal repair


A small number of meniscal tears are suitable for repair. If a tear is treated soon after it occurs and the tear itself lies in the outer part of the meniscus, where there are tiny blood vessels, it may be suitable for repair with special sutures or anchors.
In general this is only considered in the relatively younger age group for a number of technical reasons. Over the age of 30, we know that the chance of a meniscus tear healing is reduced.