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.
See Also: Knee Meniscus Anatomy

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:

  • Red-Red zone
  • Red-White zone.
  • 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).
meniscus zones
Meniscus blood supply zones

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.
meniscus tear types
Types of Meniscus Tears

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 include 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:
  1. Tear size between 1 cm and 4 cm.
  2. Vertical tear.
  3. Tears in the Red-Red zone.
  4. Meniscal root tear.
  5. 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).
    1. Inside-out technique.
    2. Outside-in technique.
    3. All-inside technique.
  • There also Meniscal Transplantation.
meniscus repair techniques
Meniscus Repair Techniques

Complications of treatment:

  1. Saphenous neuropathy .
  2. Arthrofibrosis.
  3. Sterile effusion.
  4. Peroneal neuropathy.
  5. Superficial infection.
  6. Deep infection.

Meniscus Tear Rehabilitation Exercises

Torn Meniscus Physical Therapy depends on whether ACL reconstruction was performed at the same time.

For example, if ACL reconstruction is performed concurrently with the meniscal repair, more aggressive ROM exercises should be performed although flexion should be limited to 90 degrees for the first 4–6 weeks. Although many protocols exist, the principles of Physical Therapy For Meniscus Tear include an initial period of non–weight-bearing and limitation of flexion.

Arnoczky et al. have demonstrated that the meniscus is subject only to small amounts of motion and stress between 15 and 60 degrees of knee flexion.

Meniscus Tear Rehabilitation Exercises
Meniscus Tear Rehabilitation Exercises

Lateral Meniscus Tear Exercises and Rehabilitation Protocol:

Week 1

  • Continuous passive motion (CPM): PROM 10–70 degrees (knee extension/flexion), 3 *60 min/d
  • No AROM exercises
  • Partial weight-bearing with crutches (20% of body weight)
  • Knee brace locked in extension (for 4 weeks); wear brace day and night; remove brace for exercising and CPM
  • Modalities to decrease swelling and pain: ice 6 * 10 min/d, transcutaneous electrical nerve stimulation (TENS) 2 * 20 min/d
  • Patella mobilizations, low grade, 5 min/d
  • Soft tissue massage (posterolateral, suprapatellar), 15 min/d
  • Isometric quadriceps contractions (in 20 degrees of flexion), 10 * 30 s/d
  • Electrical muscle stimulation (EMS) for quadriceps (in 20 degrees of flexion): 30 contractions per day (4-s duration [85 Hz], 20-s rest time per day)
  • Upper body ergometer aerobic program, 10 min/d
  • Upper extremity and trunk strengthening program, 30 min/d

Week 2

  • Continue with the above program
  • Partial weight-bearing with crutches (20% of body weight)
  • PROM goal: 0–90 degrees
  • AROM exercises for extension (in available range)
  • No AROM for flexion
  • Seated concentric quadriceps contractions, 60–0 degrees of flexion (against manual resistance, Theraband), 6 *20 reps/d
  • EMS for quadriceps (60 degrees of flexion), 30 contractions per day (4-s duration [85 Hz], 20-s rest time)
  • Pool exercises (gait, balance, coordination), 20 min/d

Week 3

  • Continue with the above program
  • Partial weight-bearing with crutches (50% of body weight)
  • ROM goal: 0 degree, 120 degrees, discontinue CPM when goal reached
  • Flexibility exercises for quadriceps (Thomas position), 6 * 30 s/d
  • Bilateral proprioceptive exercises (knee flexion, 10–20 degrees), on different unstable surfaces, 6 1 min/d
  • Bilateral balance exercises (Biodex Stability System), 6 * 30 s/d
  • Isokinetics (speeds 30 degrees/s and 60 degrees/s) in limited ROM (40–90 degrees of flexion) for quadriceps, 3 20 reps/d
  • Stationary bike for gentle ROM exercise (low resistance), 3 * 15 min/d

Week 4

  • Continue with the above program
  • Partial weight-bearing with crutches (70% of body weight
  • ROM goal: 0–130 degrees
  • Begin gentle AROM exercises for flexion
  • Bilateral mini-squats (0–40 degrees), 6 * 20 reps/d
  • Unilateral proprioceptive and balance training (knee flexion, 10–20 degrees), 6 * 20 s/d
  • Isometric hamstring exercises (in 0, 20, 40, 60, and 80 degrees of flexion), 6 *30 reps/d
  • Simulated leg press on the CKC attachment (Biodex Systems), range 0–60 degrees, speed 90 degrees/s, 3 * 30 reps/d
  • Deep-water running program (with wet vest), 20 min/d

Week 5

  • Continue with the above program
  • Full weight-bearing for level gait (avoid stairs), discontinue the use of crutches
  • ROM goal: ensure 0–130 degrees with active and passive exercises
  • Discontinue knee brace, use of knee neoprene sleeve
  • Flexibility exercises: add stretching for hamstrings, gastrocnemius/soleus, iliotibial hand, hip flexors, adductors, 3 * 30 s for each muscle group
  • Unilateral proprioceptive and balance training (knee flexion, 10–20 degrees), 6 *30 s/d
  • Isokinetics quadriceps (speeds, 30, 60, 90, 120, 150, and 180 degrees/s; range, 110–0 degrees), 6 * 10 reps (each speed)/d
  • Hamstring exercises (0–90 degrees of flexion) with Theraband, 5 * 20 reps/d
  • Stationary bike (increase resistance), 3 * 20 min/d

Week 6

  • Continue with the above program
  • Exercise passive flexion end of ROM (unloaded flexion), 6 * 10 min/d
  • Bilateral semi-squats (0–60 degrees), 6 * 20 reps/d
  • Bilateral reactive/quickness training, 10 * 30 s/d
  • Agility training (lateral movements with Sport Cord), 3 * 15 min/d

Week 7

  • Continue with the above program
  • “Sit back on heels” exercise (loaded flexion), 12 *1 min/d
  • Stairs allowed
  • Unilateral mini-squats (0–40 degrees), 6 * 20 reps/d
  • Isokinetics quadriceps AND hamstring (speeds 180, 210, 240, 270, and 300 degrees/s; range, 110–0 degrees),
    6 * 10 reps (each speed)/d
  • Strengthening program on weight machines (leg press, leg curls), 1 * 30 min/d
  • Endurance program on bike, 1 * 45 min/d

Week 8

  • Continue with the above program
  • PROM goal: symmetrical
  • Progress unilateral mini-squats to semisquats
  • Lunges program (front, lateral, diagonal), 3 * 25 each
  • Stairmaster, 1 *30 min/d

Week 9

  • Continue with the above program
  • Intensify strengthening (2 * 45 min/d) and endurance program (1 * 60 min/d)

Week 10

  • Continue with the above program
  • “Sit back on heels” goal: symmetrical
  • Plyometrics program (bilateral vertical and horizontal jumping), 1 * 20 min/d
  • Controlled return to sports

Week 11 to 14

  • Continue with the above program
  • If no problems, discontinue rehabilitation by end of week 12
  • Intensify sport-specific ice training until complete integration in the team training

References

  1. Bizzini M, Gorelick M, Drobny T. Lateral meniscus repair in a professional ice hockey goaltender: a case report with a 5-year follow-up. J Orthop Sports Phys Ther. 2006 Feb;36(2):89-100. doi: 10.2519/jospt.2006.36.2.89. PMID: 16494076.
  2. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
  3. Campbel’s Operative Orthopaedics 12th edition Book.
  4. Millers Review of Orthopaedics -7th Edition Book.