A discoid meniscus is a congenital (born with) variation of the normal meniscus. Instead of being shaped like a cashew nut, the meniscus is more oval or disk shaped. Occasionally, it has a normal shape with an abnormal attachment to the surrounding structures.
A discoid meniscus tends to occur in the outer (lateral) meniscus. It may cause symptoms without an injury or may become symptomatic when torn or injured.
What Is a Discoid Meniscus?
The meniscus is a cartilage structure in the knee that sits on top of the tibia (leg bone). Each knee has two menisci, an inner and an outer meniscus.
The meniscus functions like an adapter between the rounded femur (thigh bone) and flat tibia. It also helps distribute forces between the two bones over a greater area, helps supply nutrition to the articular cartilage that lines the bones, and helps stabilize the knee.
A discoid meniscus is a developmental or congenital variation of the normal meniscus. Instead of having the usual shape, it is more oval or disk shaped. Occasionally, it has a normal shape with an abnormal attachment to the surrounding structures.
Causes and Risk Factors
The cause of a discoid meniscus is unknown, but it is thought to be a developmental or congenital condition.
Risk factors include:
- Contact sports, such as football
- Sports involving cleats and pivoting, such as soccer
- Sports requiring good shoe grip and sudden changes in direction, such as racquetball and basketball
- Previous knee injury
- Associated knee injury, particularly ligament injuries
- Poor physical conditioning, including strength and flexibility
Symptoms
Frequent signs and symptoms include:
- Often, no symptoms at all
- Snapping or clunking of the knee with motion
- Pain, especially when standing on the affected leg
- Tenderness along the knee joint
- Swelling of the affected knee, which may occur immediately or one to two days after an injury
- Locking of the knee, or inability to completely straighten it
- Giving way or buckling of the knee
Treatment
If a discoid meniscus is found incidentally and does not cause symptoms, nothing needs to be done.
If injured, initial treatment may include medications and ice to relieve pain and reduce swelling. Walking with crutches until the patient can walk without a limp is sometimes recommended, although full weight may be placed on the injured leg.
Range-of-motion, stretching, and strengthening exercises may be performed at home, although referral to a physical therapist or athletic trainer may be recommended. A physician may occasionally recommend a brace, immobilizer, or crutches to protect the knee.
Arthroscopic surgery is often recommended as definitive treatment. Usually the tear is removed, although repair may occasionally be attempted.
Nonsteroidal anti-inflammatory medications, such as aspirin and ibuprofen, or other minor pain relievers such as acetaminophen, are often recommended as directed by a physician. Pain medication may also be prescribed as necessary.
Cold may be used to relieve pain and reduce inflammation for 10 to 15 minutes every two to three hours and immediately after activities that aggravate symptoms. Heat may be used before prescribed stretching and strengthening activities.
Recovery and Outcomes
Some meniscal injuries can heal on their own, while others may not heal but may cause no symptoms. If there are no symptoms, there is no known problem with leaving the meniscus alone.
The definitive treatment for meniscal tears requires surgery, which may provide complete healing in six weeks.
After surgery or immobilization, stretching and strengthening of the injured, stiff, or weakened knee and surrounding muscles are necessary. These exercises may be performed with or without the assistance of a physical therapist or athletic trainer.
Potential complications include:
- Recurrence of symptoms
- Repeated knee injury, particularly if sports are resumed too soon after injury or surgery
- Progression of an untreated tear
- Arthritis of the knee in later years, with removal of the tear or without surgery
- Infection or bleeding related to surgery
- Injury to nerves, which may cause numbness, weakness, or paralysis
- Continued pain
- Giving way or locking
- Knee stiffness or loss of motion
- Need for additional surgery
When to See Dr. Chudik
Contact Dr. Chudik’s office if symptoms worsen or if you are experiencing persistent knee symptoms such as pain, swelling, snapping, locking, or giving way.
Call 630-324-0402, request an appointment online, or email contactus@chudikmd.com