Discoid Meniscus: Knee Joints
What is meniscus?
Meniscus is a crescent-shaped piece of cartilage placed in the knee joint between thighbone and tibia. It acts as a shock absorber, allowing knee to easily bend and straighten. There are two menisci in the knee – one, on the inside of the knee called medial meniscus, and second, on the outside of the knee called lateral menisci. Meniscus is attached to the tibia bone by meniscofemoral ligament so that it stays at its place and does not hang in the knee while also providing blood supply to the meniscus.
What is discoid meniscus?
In normal conditions, meniscus is shaped like a crescent but sometimes it becomes like a half-moon or complete circle. It could occur in one or both knee. Most people get it on the lateral side (outside) of the knee. Some people with discoid meniscus never experience any problems while for others the symptoms start from childhood. This abnormal shape makes it more prone to injury. Once injured, meniscus is difficult to get healed.
There are three types of discoid meniscus:
- Complete – When tibia is totally covered by the meniscus
- Incomplete – When meniscus does not fully cover the tibia but is thicker and broader than normal.
- Hypermobile Wrisberg – When the meniscofemoral ligament is absent. In such cases, meniscus slips in the knee join causing pain or locking and popping of the knee.
What are the causes of discoid meniscus?
The definite causes are still not clear but doctors believe that an abnormal ligament may cause stretching of the meniscus during child development which leads to discoid meniscus.
What are the symptoms of discoid meniscus?
- Locking or popping of the knee
- A ‘giving away’ feeling in the knee
- Stiffness or swelling
- Inability to straighten the knee
How is discoid meniscus diagnosed?
A child suffering from knee problem is taken to a doctor who then inquires the symptoms and medical history of the child. He then examines the knee for discoid meniscus by twisting, bending and straightening the knee. In most cases of discoid meniscus, either a popping or clunking sensation can be felt.
Also, sometimes, the abnormal meniscus can be seen protruding from the side of the knee under the skin. Doctors may also ask for certain tests like X-rays or MRI scan.
How is discoid meniscus treated?
Knee arthroscopy, a surgical procedure, is done to treat discoid meniscus. Using arthroscope, tears of meniscus are either removed or abnormal meniscus is repaired. It is performed under the effect of general anaesthesia. Knee arthroscopy is done on out-patient basis where you can return home within few hours. Treatment for discoid meniscus is advised only when there is pain or other symptoms. If there is no discomfort, treatment can be avoided.
How much time it takes for recovery?
After surgery, doctor may advice use of brace, crutches or wheelchair to avoid putting any pressure on the knee joint. Taking adequate rest allows initial healing to complete fast.
Avoid active sports or excessive movements that overstress the knee. After which physical therapy exercises (under the guidance of trained physical therapist) are advised to regain the strength and mobility of the knee. Most patients return to normal routine after 2-3 weeks.