Description

• The menisci are fibrocartilaginous structures between the femoral condyles and the tibial plateaus.
• The menisci help stabilize the knee and distribute forces across the joint.
• Meniscal tears can lead to knee pain and disability and, ultimately, are a risk factor for the development of knee osteoarthritis (OA).

Pediatric Considerations

• Meniscal injuries are rare in children aged <10 years. In this population, they are often due to a discoid meniscus.
• MRI is still the study of choice but is less sensitive and specific for diagnosing meniscal tears in children aged <12 years.

Epidemiology

Bimodal age distribution—young athletes (traumatic) and older patients (degenerative)

Incidence
Medial meniscus more commonly injured

Prevalence
One of the most common musculoskeletal injuries

Etiology and Pathophysiology

• Traumatic tears are acute. They generally occur due to a twisting motion of the knee with foot planted.
  • Common in younger patients (aged <40 years) without underlying knee OA
• Degenerative tears are chronic. They generally occur with overuse and minimal trauma.

Genetics
No specific gene locus has been identified.

Risk Factors

• Nonmodifiable risk factors: male, discoid meniscus, ligamentous laxity
• Traumatic tear:
  • High degree of physical activity (especially cutting sports)
• Anterior cruciate ligament (ACL) insufficiency
• Degenerative tear:
  • Increased age (>60 years)
  • Obesity
  • Work-related kneeling/squatting/climbing stairs

General Prevention

• Treatment and rehabilitation of previous knee injuries, particularly ACL injuries
• Strengthening and increased flexibility of quadriceps and hamstring muscles
• Weight management

Commonly Associated Conditions

• Traumatic tear: ACL concomitantly torn in 1/3 of cases
• Degenerative tear: OA, Baker cyst (greater association with medial meniscal tears)