What is a discoid meniscus?
A healthy meniscus is crescent-shaped, tough, rubbery cartilage located in the knee joint between the femur (thighbone) and the tibia (shinbone). Each knee has two menisci, one lateral (on the outside) and one medial (on the inside). They act as shock absorbers between the tibia and femur during locomotion (walking, running, sports), and help stabilize the joint. A discoid meniscus is irregularly shaped, often oval-shaped. It can also be thicker than normal, which makes the meniscus more prone to injury, tears and pain that can start as early as childhood. Essentially, a discoid meniscus is larger and thicker than a normal meniscus; too much meniscus tissue persists during embryonic development and leads to a discoid shape. Many individuals can go their entire lives without experiencing issues from their discoid meniscus; however, those who do may require discoid meniscus repair or reconstruction. There are three types of discoid menisci:
- Complete: The meniscus covers the tibia (shinbone) entirely
- Incomplete: The meniscus is thicker or wider than normal
- Hypermobile Wrisberg: The ligaments that attach the menisci to the tibia and femur (thigh bone) do not exist, which causes popping, locking and pain in the knee