Discoid Meniscus

What is a discoid meniscus?

The meniscus is the cartilage in the knee that cushions the joint between the femur (thighbone) and tibia (shinbone). A discoid meniscus is a congential anomaly where the meniscus is abnormally shaped. Instead of a crescent moon shaped cartilage pad in the knee joint, it resembles a half moon or a disc, like its name, and is thicker than normal.

There are three types of discoid meniscus:

Incomplete: the meniscus is slightly wider and thicker than normal
Complete: the meniscus covers the entire tibia
Hypermobile Wrisberg: the shape of meniscus is normal, but the ligament that attaches it to the back of the knee is missing, leaving the mensicus too mobile or unstable

What causes a discoid meniscus?

While the cause of discoid meniscus is unknown, it is a congenital anomaly that happens in utero causing the meniscus in the knee to deviate from the typical shape.

What are symptoms caused by a discoid meniscus?

While a discoid meniscus may never become symptomatic, symptoms usually begin during childhood and can include:

pain or tenderness in the knee
stiffness in the knee
swelling of the knee
locking of the joint
a popping sensation
buckling (feeling of instability)
inability to fully extend the knee

Due to the thick, abnormal shape of a discoid meniscus, it makes it more prone to injury or tearing. Injury usually occurs with sudden stopping or twisting motions to the knee.

What are treatments options for a discoid meniscus?

Although some people with discoid meniscus may never experience symptoms, the shape and thickness of the cartilage puts them at a higher risk for injury, such as tearing. Once the meniscus is torn, surgery is required as cartilage is not capable of healing itself after injury.

If surgery is recommended for patients, post-operative treatments may include: