Discoid lateral meniscus

What are the symptoms of discoid lateral meniscus?

Individuals with a discoid meniscus might not face any issues throughout their lives. When the discoid meniscus doesn't lead to any pain, clunking, instability or discomfort, there's no necessity for treatment. 

Nonetheless, some individuals may encounter knee issues linked to the discoid meniscus, with symptoms frequently starting in childhood.

Symptoms of a discoid lateral meniscus can vary but often include:

• Knee pain, especially along the outer (lateral) side

• Swelling or stiffness in the knee

• A loud popping or clicking sound during movement, often when straightening the knee from a bent position. A video of this can be seen below.

• Limited range of motion

• The sensation of the knee locking or giving way

What causes discoid lateral meniscus?

The exact cause of discoid lateral meniscus is not well understood, but it is believed to be congenital (present at birth). It might not present symptoms until later in life, especially after an injury or during physical activities or during the growth phase of adolescence.

How do you diagnose discoid lateral meniscus?

Diagnosis involves a combination of history of symptoms suffered including pain, clunking, giving way, and physical examination.  

MRI (Magnetic Resonance Imaging) is the most reliable test to diagnose discoid lateral meniscus.

MRI allows the shape and position of the lateral meniscus to be assessed and also whether there is an associated tear of the discoid lateral meniscus. 

What is the best treatment for discoid lateral meniscus?

Treatment for discoid lateral meniscus depends on the severity of the symptoms and the extent of the condition. Options include:

Conservative Treatment: If there is no pain, locking or painful clunking and normal activities are not affected, the meniscus can be left alone.  Initial treatment of occasional flares involves rest, ice, compression, and elevation (RICE). Physical therapy and exercises to strengthen the knee and improve flexibility can also be beneficial.

Medication: Anti-inflammatory medications can help reduce pain and swelling.

Surgical Intervention: In cases where conservative treatments are not effective, surgery may be necessary. 

When is surgery required for discoid lateral meniscus?

Surgery is indicated when:

• There are frequent occurrences of painful clunking 

• there is frequent locking or giving way

• Activities such as running, sports, twisting or turning are affected regularly. 

• There is a clear tear of the meniscus that is symptomatic.

• There is a collection of fluid around the tear known as a parameniscal cyst of the lateral meniscus

• There is a dislocated (bucket handle type) tear of the meniscus 

What does surgery for discoid lateral meniscus involve?

Surgery usually involves a keyhole procedure for discoid lateral meniscus known as arthroscopy.

Although arthroscopy of the knee is a widely conducted orthopaedic operation, discoid meniscus, especially in a child or young adult, should be treated by a surgeon who regularly treats such conditions and has experience in meniscal repair.

In this procedure, a surgeon makes several small cuts near the knee to insert an arthroscope, a tiny camera, into the joint. This camera projects images onto a screen, which the surgeon uses to navigate small surgical tools. Typically, patients undergo arthroscopic surgery as outpatients and return home a few hours later.

Most arthroscopy is performed using a combination of general and local anaesthesia.

The surgical approach varies based on the condition of the discoid meniscus being treated.

The goal of surgery is to reshape the meniscus to a more normal structure, which will allow for better function and stability of the knee joint. Often, the abnormal shape is associated with a tear in the meniscus which needs repair.

Rarely is the tear so bad that the meniscus requires removal, but this can occur in some instances.

Saucerisation, which involves reshaping the meniscus into a more typical crescent shape by cutting, is the usual treatment for both complete and incomplete discoid menisci.

In cases where the discoid meniscus is torn, the procedure may include saucerization followed by repair of the torn tissue using stitches. In some instances some of the torn tissue may require removal but the goal of surgery is to preserve as much "normal meniscus tissue as possible.

For the hypermobile Wrisberg variant of discoid meniscus, the procedure may involve saucerization followed by stabilisation, where the meniscus is sutured to the joint lining or anchored back into the bone (root repair) if necessary.

Recovery and Rehabilitation

Post-treatment, whether surgical or conservative, rehabilitation plays a crucial role in recovery. This may involve a period on crutches that can vary between 5 days and 6 weeks. If the meniscus has been repaired, there may be a period in a brace. A tailored physical therapy program will help restore knee function, improve strength, and reduce the risk of future injuries. Recovery time varies depending on the treatment method and the individual's condition.

Prevention and Management

As discoid meniscus is a condition that people are born with, it cannot be prevented. However, maintaining good knee health through regular exercise, proper technique in sports, and avoiding unnecessary stress on the knees can help manage symptoms and reduce the risk of complications.

When to See a Doctor

If you experience persistent knee pain, swelling, or any symptoms affecting your knee's function, consult a healthcare professional for an accurate diagnosis and appropriate treatment.