Meniscus tear

Last updated: June 14, 2023

Summarytoggle arrow icon

A meniscal tear can be caused by trauma or degenerative changes in the knee joint. Traumatic meniscal tears are usually associated with physical activity and typically result from rotation coupled with axial loading of the knee joint. The affected meniscus may be medial or lateral, with the medial frequently torn because of its relative immobility. Clinical features include pain and limited range of movement of the affected knee. Key features are slow onset joint effusion and a characteristic popping or clicking sensation during joint maneuvers. MRI is used to confirm the diagnosis. Arthroscopy enables simultaneous surgical intervention, especially in patients with persistent symptoms, inner zone tears, and functional limitations. Conservative treatment (i.e., rest, ice, leg elevation, and analgesia) may be considered in small meniscal tears of the outer vascular zone and patients with pre-existing degenerative changes.

Etiologytoggle arrow icon

  • Young, active patients: traumatic (i.e., axial loading and rotation action with a fixed foot during physical activity)
  • Older patients: degenerative (e.g., continuous work in a squatting position)

Classificationtoggle arrow icon

A meniscus tear may be medial or lateral. The medial meniscus is more commonly injured than the lateral meniscus.

  • Location of the tear
    • White zone: inner third, avascular area
    • Red-white zone: middle third, poorly vascularized area
    • Red zone: outer/peripheral third, vascularized area
  • Type of tear
    • Longitudinal tear (vertical tear): perpendicular to the tibial plateau
    • Radial tear: perpendicular to the tibial plateau and the longer axis of the meniscus
    • Horizontal tear: parallel to the tibial plateau
    • Displaced tears
      • Bucket handle tear: displaced and extensive longitudinal tear that splits the meniscus into two parts that remain connected at the anterior and posterior ends
      • Parrot beak tear: displaced radial tear
      • Flap/oblique tear: displaced longitudinal or horizontal tear
    • Simple or complex meniscal tear (a combination of horizontal, longitudinal, and radial meniscal tears)

Clinical featurestoggle arrow icon

  • Knee pain: exacerbated by weight‑bearing or physical activity
  • Joint line tenderness (medial or lateral)
  • Restricted knee extension with possible knee instability
    • Locked knee may occur if the torn meniscus obstructs knee movement.
    • May hear clicking sound or have a popping or locking sensation
  • Intermittent joint effusions
    • Tears in the medial, white zone → serous effusion
    • Tears in the red zone near the base of the meniscus bloody effusion (hemarthrosis)
    • Patellar tap test: a maneuver used to assess knee joint effusion
      • Procedure
        • Patient lies in a supine position with the knee in full extension
        • The examiner applies pressure to the thigh toward the proximal part of the knee and to the lower leg, directly below the patella
        • While maintaining this position, the examiner gently presses down on the patella.
      • Findings
        • Positive test: A floating or swimming patella that can be pressed down toward the femur resulting in a palpable tap suggests a knee effusion.
        • Negative test: if no effusion is present, then the patella is located directly on the femur and cannot be displaced

Signs of meniscus injury

Test procedure Findings
McMurray test [1]
  • Pain on palpation
  • Palpable or audible pop/click with maneuvers
Steinman test
  • The patient lies supine and flexes their hip and knee.
  • The examiner fixes the bent knee with one hand.
  • The examiner grasps the foot with their other hand and rotates the tibial head internally and externally.
Apley grind test
  • Similar to the Steinman test but performed in a prone position
  • The patient lies prone and flexes their knee to 90°.
  • The examiner holds the thigh in place with one hand (or knee as seen in the video).
  • The examiner grasps the foot with their other hand and pulls/pushes on the foot while internally and externally rotating the tibia.
Thessaly test
  • With the examiner's help, the patient stands flat-footed on the affected leg at 20° of knee flexion.
  • The patient then rotates their knee externally and internally.
Payr test
  • The patient sits cross-legged.
  • The examiner applies pressure from above on both knees simultaneously.
Bohler sign
  • The patient lies supine and slightly flexes their knee and hip.
  • The examiner lifts the leg with one hand while maintaining the knee in an attitude of flexion.
  • With the other hand, the examiner grasps the lower leg and applies adducting (varus) and abducting (valgus) forces on the knee joint.

Diagnosticstoggle arrow icon

Differential diagnosestoggle arrow icon

Meniscus tear Knee ligament injuries
  • Axial loading and rotation action with a fixed foot or degenerative changes
Clinical features
  • Delayed and slow onset joint effusions
  • Palpable pop, clicking, or locking with maneuvers
  • Rapid onset knee effusion
  • Absent popping sensation

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Referencestoggle arrow icon

  1. Lawry GV. Fam's Musculoskeletal Examination and Joint Injection Techniques. Elsevier Health Sciences ; 2010

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