Discoid Meniscus
Have you ever experienced a decreased range of motion in the knee, clicking or popping sounds? If so, you may have a discoid meniscus. A discoid meniscus is an abnormally shaped and enlarged meniscus in the knee. Because of its shape, it is more prone to injury. Its thick, abnormal shape makes it more likely to tear or get stuck in the knee. While many people are unaware of this issue and it never bothers them, others will have knee problems which can result in instability of the knee and lasting pain. The condition is rare, so it is important to seek out a highly trained and experienced orthopedic specialist. The place to start is Colorado Center of Orthopaedic Excellence in Colorado Springs, Colorado.
OVERVIEW
A discoid meniscus is a congenital, structural defect and does not grow into the normal shape of a healthy meniscus. The tissue grows thicker and larger and also has an abnormal texture. No sudden change occurs in discoid development after birth. The pathology is usually presented in the young population and during adolescence. Because of the high rate of asymptomatic patients, it’s difficult to estimate the actual incidence of discoid meniscus, but it is thought to be present in 3-5% of the general population. It occurs more in males than females and there is a slightly higher prevalence in Asians. A discoid meniscus is encountered more on the lateral or outer side of the knee and in 25% of cases it is bilateral.
ABOUT THE MENISCUS
The meniscus is a wedge-shaped piece of cartilage that sits between the bones of the knee. Each knee has two menisci; the medial meniscus on the inside of the knee, and the lateral meniscus on the outside. Healthy menisci are shaped like crescent moons (in fact, “meniscus” comes from the Greek word for “crescent”). The meniscus acts as a shock absorber between your femur (thighbone) and tibia (shinbone). It protects the thin articular cartilage that covers the ends of the bones and helps the knee to easily bend and straighten. The menisci are attached to the femur bone by a strong tissue called the meniscofemoral ligament. This ligament also provides a blood supply to a small portion of the meniscus.
WHAT IS DISCOID MENISCUS?
There are three types of discoid menisci:
Incomplete—the meniscus is slightly thicker and wider than normal, usually asymptomatic
Complete—the meniscus completely covers the tibia
Hypermobile Wrisberg—this occurs when the ligaments that attach the meniscus to the femur and tibia are not there. Without these ligaments, even a fairly normally shaped meniscus can move around in the joint and cause pain, as well as locking and popping of the knee. A discoid meniscus is more prone to injury than a normal meniscus. The thick, abnormal shape of a discoid meniscus makes it more likely to get stuck in the knee or to tear. If the meniscofemoral ligament attachment to the femur is also missing, the risk for injury is even greater. Once injured, even a normal meniscus is difficult to heal. This is because the meniscus lacks a strong blood supply and the nutrients that are essential to healing cannot reach the injured tissues.
Read more about Discoid Meniscus on our new Colorado Springs Orthopedic News Site – Colorado Springs Orthopedic News. Schedule an appointment with an ankle specialist today.
