Huw David

Knee cartilage Injuries (Meniscal)

Huw David treats knee cartilage injuryThe knee is the largest joint in the body. Each knee has two menisci, the medial and lateral menisci. They are discs of gristle or cartilage (fibrocartilage) sandwiched between the femur (thigh bone) and tibia (shin bone). They act as shock absorbers, cushioning the loads passing through the joint. They also provide a degree of stability to the joint.

Although the menisci are relatively robust, particularly in the young, damage to one or other is common and is a reflection on the high demands we place on our knees. In the younger age group damage may occur with sporting activities such as turning or pivoting on the knee. With age, the menisci become more friable and tears can occur with less trauma. Twisting the knee stepping off a kerb awkwardly or squatting down may lead to a tear.

We recognise certain patterns of meniscal tears and vertical tears with or without an unstable flap of torn meniscus are more common than horizontal or cleavage tears. Medial meniscal tears are more common than tears of the lateral (outer) meniscus.

Some tears are small and will cause few if any symptoms. Larger tears may give rise to pain and swelling. Catching and intermittent locking of the joint, particularly with twisting movements, are characteristic of a torn meniscus.

The diagnosis can usually be made based on just the history and physical examination. Xrays are unlikely to help, other than to possibly highlight arthritis that is commonly associated with tears in older people. An MRI scan is occasionally indicated as, for example, to exclude other injuries to the joint.

The meniscus has a poor blood supply and nothing in the body will heal without blood. Those tears close to the margin of the joint will be in a zone supplied with blood and may be suitable to an arthroscopic repair. The majority of tears occur within that part of the meniscus lacking a blood supply and are usually treated by an arthroscopic resection of just the damaged portion.