Discoid meniscus

Discoid Meniscus

Diagram of a discoid meniscus.

The discoid meniscus is an anatomical variant of the knee meniscus, characterized by a thicker and more disc-like shape compared to the normal crescent-shaped meniscus. This condition can affect the lateral meniscus of the knee and is often associated with knee pain and mechanical symptoms.

Anatomy

The menisci are two crescent-shaped fibrocartilaginous structures located in the knee joint. They serve to distribute weight, absorb shock, and stabilize the joint. The discoid meniscus deviates from the typical shape, appearing more circular and thicker, which can lead to altered biomechanics of the knee.

Types

Discoid menisci are classified into three types based on their morphology and stability:

• Complete discoid meniscus: Covers the entire tibial plateau.
• Incomplete discoid meniscus: Covers a significant portion but not the entire plateau.
• Wrisberg-ligament type: Lacks normal posterior attachments, leading to increased mobility.

Etiology

The exact cause of discoid meniscus is not well understood, but it is believed to be a congenital condition. It is more commonly observed in the lateral meniscus and is prevalent in certain populations, such as those of Asian descent.

Clinical Presentation

Patients with a discoid meniscus may present with knee pain, swelling, and mechanical symptoms such as clicking, locking, or giving way. These symptoms often arise due to tears or degeneration of the abnormal meniscus.

Diagnosis

MRI of a discoid meniscus.

Diagnosis is typically made through clinical examination and imaging studies. Magnetic resonance imaging (MRI) is the preferred method for visualizing the discoid meniscus and assessing any associated tears or abnormalities.

Treatment

Treatment options depend on the severity of symptoms and the presence of meniscal tears. Conservative management includes physical therapy and pain management. Surgical intervention, such as arthroscopic meniscectomy or meniscoplasty, may be necessary for symptomatic cases.

Prognosis

The prognosis for individuals with a discoid meniscus varies. Many patients respond well to conservative treatment, while others may require surgical intervention to alleviate symptoms and restore knee function.

Related Pages

• Meniscus (anatomy)
• Knee joint
• Arthroscopy