• Partial or complete tear of 1 or both menisci (semicircular fibrocartilaginous structures, located between the femoral condyles and tibial plateau) that is usually caused by injury or age-related degeneration.
• Menisci = Cartilage NOT ligament.

Classification:

• Location of the tear:
  • White zone: Inner third, avascular area.
  • Red-white zone: Middle third, poorly vascularised area.
  • Red zone: Outer third, vascularised area.
• Type of tear:
  • Longitudinal/vertical tear.
  • Radial tear.
  • Horizontal tear.
  • Displaced tear:

    • Bucket handle tear.

    • Parrot beak tear.

    • Flap/oblique tear.

      

Demographics

• M > F.
• Acute tears: Young, active patients (<40yo).
• Degenerative tears: Old patients (>40yo).

Risk Factors

• Acute tears: Acute traumatic event. i.e. sports that involve axial loading and rotation with a fixed foot such as netball, soccer, basketball or rugby.
• Degenerative tears: Older age (> 40 years), male gender, work-related kneeling and squatting (> 1 hour/day), and stair climbing (> 30 flights/day).
• High BMI.

Mechanism of Injury

• Meniscal injuries result from either mechanical or biochemical (degenerative) causes.