Knee Meniscus Tear

January 27, 2021 | By : OrthoFixar | Sports Medicine
| Last updated on February 17, 2021


  • Knee Meniscus Tear is among the most common sport injury seen by orthopedic surgery.
  • The medial meniscus is torn approximately three times more often than the lateral meniscus.
  • Lateral meniscus tears occur more commonly with concomitant ACL tear
  • Traumatic meniscus tears are common in young patients with sports-related injuries.
  • While degenerative meniscus tears usually occur in older patients.
  • Meniscus anatomy has been discussed previously.

Mechanism of the meniscus tear

  • Meniscus Tear usually occurs by a rotational force incurred while the joint is partially flexed.

Classification

Classification based on the location of the meniscus tear:

  • The tear may occurs at:
    1. Red-Red zone
    2. Red-White zone.
    3. White-White zone.
  • It’s also classified as it may occur at:
    • Posterior third of the meniscus (Posterior horn)
    • Middle third of the meniscus.
    • Anterior third of the meniscus (Anterior horn).

Classification based on the shape (Pattern) of the meniscus tear:

Type of tearCharacteristics
Vertical longitudinal– The most Common (especially in the setting of ACL tears).
– It can be repaired if located in the peripheral third of the meniscus.
Bucket-handle– A vertical longitudinal tear displaced into the notch.
– Double PCL sign.
Radial– Starts centrally and proceeds peripherally.
– It’s not repairable because of loss of circumferential fiber integrity.
Flap– Begins as a radial tear and proceeds circumferentially.
– May cause mechanical locking symptoms.
Horizontal cleavage– Occurs more frequently in the older population.
– May be associated with meniscal cysts.
Complex– A combination of tear types.
– More common in the older population.

Clinical Evaluation:

Symptoms and signs:

  1. localized Pain and tenderness at the medial or lateral side of the knee (based on the injured meniscus).
    • The meniscus itself is without nerve fibers except at its periphery; therefore, the tenderness or pain is related to synovitis in the adjacent capsular and synovial tissues.
  2. Locking of the knee: it is usually occurs only with longitudinal tears and is much more common with bucket-handle tears, usually of the medial meniscus.
  3. A sensation of “giving way” or snaps, clicks, catches, or jerks in the knee may be described by the patient.
  4. Swelling (Effusion) of the knee due to hemarthrosis that can occur when the vascularized periphery of a meniscus is torn (The absence of an effusion or hemarthrosis does not rule out a tear of the meniscus).
  5. Atrophy of the musculature around the knee, especially of the vastus medialis muscle (suggests a recurring disability of the knee).

Physical Examination:

  1. McMurray test.
  2. Apley grinding test.
  3. Ege’s test.
  4. Thessaly test.

Radiographic Evaluation

Radiographs:

  • Recommended views:
    • Anteroposterior, lateral, and intercondylar notch views with a tangential view of the inferior surface of the patella.
  • They are essential to exclude osteo-cartilaginous loose bodies, osteochondritis dissecans, and other pathological processes that can mimic a torn meniscus.

MRI:

  • It’s a noninvasive procedures.
  • MRI has been shown to have 98% accuracy for medial meniscal tears and 90% for lateral meniscal tears.

Treatment of torn Meniscus

Non-Operative treatment:

Indications:

  1. An incomplete meniscal tear or a small (5 mm) stable peripheral tear with no other pathological condition, such as a torn anterior cruciate ligament.
  2. Tears associated with ligamentous instabilities can be treated nonoperatively if the patient defers ligament reconstruction or if reconstruction is contraindicated.
    • Removal of the menisci, especially the medial meniscus, in such knees may make the instability even more severe.
  3. Meniscus tears in the absence of intermittent swelling, catching, locking, or giving way.

Methods:

  1. Knee immobilizer worn for 4 to 6 weeks (groin-to-ankle cylinder cast).
  2. Progressive isometric exercise program during the time the leg is in the cast to strengthen the muscles around the knee.
  3. At 4 to 6 weeks, the immobilization is discontinued and the rehabilitative exercise program for the muscles around the hip and knee is intensified.

Operative Treatment:

Partial meniscectomy:

  • Tears that are not amenable to repair (e.g., peripheral, longitudinal tears).
  • Complex, degenerative, and central/radial tears are treated with resection of a minimal amount of normal meniscus.

Meniscus repair:

Indications:
  • Tear size between 1 cm and 4 cm.
  • Vertical tear.
  • Tears in the Red-Red zone.
  • Meniscal root tear.
  • Age younger than 40 years.
Methods:
  • There are 4 techniques used to repair a torn meniscus:
    1. Open Surgical repair:
      • It’s uncommon technique except in trauma (knee dislocations).
    2. Inside-out technique.
    3. Outside-in technique.
    4. All-inside technique.
  • There also Meniscal Transplantation.

Complications of treatment:

  • Saphenous neuropathy .
  • Arthrofibrosis.
  • Sterile effusion.
  • Peroneal neuropathy.
  • Superficial infection.
  • Deep infection.

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