Meniscus articularis – Function, Injury and Treatment

What is the Meniscus articularis?

The meniscus articularis is a crescent-shaped or wedge-shaped fibrocartilaginous disc located within certain joints of the human body. The term derives from Latin and translates approximately as articular meniscus. Menisci are found in several joints, but are best known in the knee joint, where a medial (inner) and a lateral (outer) meniscus are present.

These structures consist primarily of type I collagen, making them significantly stronger than the hyaline cartilage covering the joint surfaces. They are attached to the joint capsule and have a limited blood supply, which restricts their capacity for self-repair after injury.

Function and Importance

The meniscus articularis serves several essential functions within the joint:

• Shock absorption: It absorbs compressive forces and protects the underlying articular cartilage.
• Load distribution: It increases the contact area between the joint surfaces, distributing mechanical loads more evenly.
• Stabilization: It contributes to the mechanical stability of the joint, particularly during rotational movements.
• Proprioception: It contains nerve endings that relay information about joint position and movement to the brain.
• Lubrication: It helps distribute synovial fluid throughout the joint, reducing friction.

Occurrence in Different Joints

Although the term meniscus articularis is most commonly associated with the knee joint, similar fibrocartilaginous structures are found in other joints as well:

• Knee joint (articulatio genus): Medial and lateral menisci – the most well-known and clinically significant menisci.
• Temporomandibular joint (articulatio temporomandibularis): Articular disc acting as a buffer between the skull base and the mandible.
• Acromioclavicular joint (articulatio acromioclavicularis): An inconstant meniscus between the scapula and clavicle.
• Distal radioulnar joint (articulatio radioulnaris distalis): Fibrocartilaginous disc between the ulna and the carpals.

Common Conditions and Injuries

The meniscus is one of the most frequently injured structures in the musculoskeletal system. Typical conditions include:

Meniscal Tear (Meniscal Lesion)

Meniscal tears often result from sudden rotational movements, twisting forces, or degenerative changes with aging. Various tear patterns are recognized: longitudinal tears, bucket-handle tears, radial tears, and flap tears. Symptoms include pain, swelling, restricted range of motion, and a clicking or locking sensation in the knee.

Meniscal Degeneration

Over time, the meniscus loses elasticity and structural integrity. Degenerative meniscal changes are frequently associated with knee osteoarthritis (gonarthrosis) and are most common in older adults.

Meniscal Cyst

Fluid accumulation within or adjacent to the meniscus can lead to cyst formation, causing pain and a palpable swelling on the side of the knee.

Diagnosis

Diagnosis of meniscal injuries is based on a combination of:

• Clinical examination: Specific tests such as the McMurray test, the Apley test, or the Thessaly test provide diagnostic clues for meniscal lesions.
• Magnetic resonance imaging (MRI): MRI is the imaging modality of choice and allows precise assessment of the location and extent of a meniscal tear.
• Arthroscopy: Joint endoscopy serves both diagnostic and therapeutic purposes and is considered the gold standard.

Treatment

Treatment depends on the type, extent, and location of the injury, as well as the age and activity level of the patient:

Conservative Treatment

Small, stable tears in the well-vascularized outer zone of the meniscus may be managed conservatively: rest, ice application, physiotherapy, and anti-inflammatory medications (e.g., NSAIDs) are typical measures.

Surgical Treatment

Larger or symptomatic tears may require surgical intervention:

• Meniscal repair (meniscal refixation): The tear is sutured arthroscopically – preferred in younger patients with good healing potential.
• Partial meniscectomy: The damaged portion of the meniscus is removed. This should be performed as sparingly as possible to protect the articular cartilage.
• Meniscal transplantation: In rare cases, a donor meniscus may be transplanted to restore joint function.

Rehabilitation and Prognosis

Following a meniscal injury or surgery, targeted physiotherapy is essential for full restoration of joint function. The prognosis depends on the nature of the injury, the treatment approach, and consistent follow-up care. Total removal of the meniscus (total meniscectomy) significantly increases the long-term risk of knee osteoarthritis and is therefore avoided in modern practice.

References

1. Kohn, D. (Ed.): Das Knie, 2nd edition. Thieme Verlag, Stuttgart 2005.
2. Englund, M. et al.: Incidental Meniscal Findings on Knee MRI in Middle-Aged and Elderly Persons. New England Journal of Medicine, 359(11):1108-1115, 2008.
3. Beaufils, P. et al.: Clinical practice guidelines for the management of meniscal lesions and isolated lesions of the anterior cruciate ligament of the knee in adults. Orthopaedics and Traumatology: Surgery and Research, 95(6):437-442, 2009.