Meniscal Injury

Basics

Description

  • The menisci are fibrocartilaginous structures between the femoral condyles and 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 <10. In this population, they are often due to a discoid meniscus and not trauma (1).
  • MRI is still the study of choice but is less sensitive and specific for diagnosing meniscal tears in children <12.
  • Meniscal repair is an effective treatment option with good clinical outcomes in the pediatric/adolescent population.

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, affecting 0.6 to 8 per 1000 patients each year (2)

Etiology and Pathophysiology

  • Traumatic tears are acute. They generally occur due to a twisting motion of the knee with foot planted.
  • Degenerative tears are chronic. They generally occur with overuse and minimal trauma.

Genetics
No specific gene locus has been identified.

Risk Factors

  • Traumatic tear:
    • High degree of physical activity (especially cutting sports)
    • Younger patients
    • Anterior cruciate ligament (ACL) insufficiency
    • Underlying meniscal degeneration—can still increase risk of meniscal tear even in traumatic event (2)
  • 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:
    • Baker cyst—greater association with medial meniscal tears
    • Osteoarthritis (OA)

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