• Clinical science

Meniscus tear

Abstract

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.

Etiology

  • 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)

References:[1][2]

Classification

  • A meniscus tear may be medial or lateral
  • 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
    • Tears may also be simple or complex.

References:[2][1]

Clinical features

  • Knee pain: exacerbated by weight‑bearing or physical activity
  • Joint line tenderness (medial or lateral)
  • Restricted knee extension with 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 (see dancing patella sign)
    • Tears in the red zone near the base of the meniscus → bloody effusion (hemarthrosis)
    • Tears in the medial, white zone → serous effusion
Signs of meniscus injury Test procedure Findings
McMurray test
  1. Patient lies in the supine position
  2. The examiner flexes the knee to 45°
  3. The examiner holds the medial side knee in one hand and ankle in the other hand.
  4. The examiner then externally rotates the leg and brings the knee into extension.
  • Pain on palpation
  • Palpable or audible pop/click with maneuvers
Apley grind test
  1. The patient lies prone and flexes their knee to 90°.
  2. The examiner holds the thigh in place with one hand (or knee as seen in the video).
  3. The examiner grasps the foot with their other hand and pulls/pushes on the foot while internally and externally rotating the tibia.
Thessaly test
  1. With the examiner's help, the patient stands flat-footed on the affected leg at 20° of knee flexion.
  2. The patient then rotates their knee externally and internally.
  • Medial or lateral joint line pain with rotation
  • Clicking noise
  • Patient may feel that their knee is locking or catching.
Steinman test
  1. The patient lies supine and flexes their hip and knee.
  2. The examiner fixes the bent knee with one hand.
  3. The examiner grasps the foot with their other hand and rotates the tibial head internally and externally.
Bohler sign
  1. The patient lies supine and slightly flexes their knee and hip.
  2. The examiner lifts the leg with one hand while maintaining the knee in an attitude of flexion.
  3. With the other hand, the examiner grasps the lower leg and applies adducting (varus) and abducting (valgus) forces on the knee joint.
Payr test
  1. The patient sits cross-legged.
  2. The examiner applies pressure from above on both knees simultaneously.

References:[2][1]

Diagnostics

  • X-ray : to exclude degenerative joint changes
  • MRI (imaging modality of choice) : identifies the location and extent of meniscal tears
    • Hyperintense line in meniscus with distorted meniscal morphology
    • Empty groove in the case of bucket handle tears
  • Arthroscopy: both diagnostic and therapeutic with a sensitivity and specificity of ∼ 100%
    • Diagnostic step of choice if MRI is contraindicated (e.g., patient with metal prostheses)

References:[2][1]

Differential diagnoses

Meniscus tear Knee ligament injuries
History
  • 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.

Treatment

  • Conservative treatment
    • Indications: pre‑existing degenerative changes in the knee joint (especially among older patients)
    • Approach
      • Rest, ice, and elevation of affected limb
      • Analgesia (NSAIDs)
      • Physical therapy (e.g., strengthening the quadriceps)
  • Surgical treatment
    • Indication: persistent disabling symptoms/effusions, functional limitations, complex tears
    • Procedure
      • Arthroscopy
        • Partial meniscectomy: tears that cannot be repaired
        • Meniscal repair: Fresh tears in the peripheral, vascular red zone (e.g., bucket handle tear near the base of the meniscus) can be sutured.
      • Meniscus transplantation
    • Postoperative care: physical therapy followed by gradual return to active physical activity.

References:[2][1]

Complications

References:[1]

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