Meniscal Tears

Turning or twisting injuries of the knee may cause tearing of the meniscus. Meniscal tears may also be the result of wear and tear with no history of acute injury.

Anatomy

The menisci are C shaped cartilage structures that serve very important functions in the knee. The medial and lateral menisci function as shock absorbers in force transmission across the knee and aid in knee joint stability. The meniscus protects the articular cartilage in the knee from wear and tear by providing a larger surface area of support for each unit of force transmitted across the knee.

Meniscal Injuries

Meniscal tears usually occur as a result of twisting or turning injuries. They may also occur as a result of long term wear and tear resulting in degenerative meniscal tears. They may present as an isolated injury or in combination with a ligament tear.

Patients usually complain of pain, swelling and recurrent painful snapping or popping within the knee. Occasionally locking or giving way of the knee are also symptoms of a meniscal injury.

On physical exam patients usually demonstrate tenderness along the medial or lateral joint lines. Sometimes a popliteal cyst posterior to the knee occurs as a result of a meniscal tear. Treating the meniscal tear usually takes care of the cyst as well. A special diagnostic maneuver called the McMurray test is performed in an attempt to catch or pinch the torn meniscus within the knee joint recreating the painful symptoms. A positive test is significant evidence of the meniscal tear however a negative result does not rule it out completely.

Diagnostic tests include plain x-rays to evaluate the knee for bony abnormality such as arthritis, loose bodies and fractures. A MRI can be performed to visualize the meniscal tear but often the diagnosis can be made from the patient's clinical exam and history.

Treatment

Unless the patient presents with a locked knee (inability to fully extend or flex), initial treatment for meniscal tears includes range of motion and strengthening exercises, anti-inflammatory medications and ice to reduce the pain and inflammation. Most meniscal tears do not heal on their own but they may become asymptomatic over time.

If symptoms persist for more than 4-6 weeks or if patients present with a locked knee, arthroscopic treatment is usually recommended. Most meniscal tears are treated by partial excision however in younger people, with better meniscal blood supply; the tear may be repairable.

Following arthroscopy, which is usually performed in an outpatient setting, patients begin a rehabilitation program of range of motion and strengthening exercises. They usually require the support of crutches for comfort for a few days and usually return to full activities within 4-6 weeks. If a meniscal repair is performed, return to full sports may not occur for at least 6 months.

Diagnosing Meniscal Tears

Symptoms

• Pain
• Swelling
• Poping or Locking

Signs

• Joint line tenderness
• Popliteal Fullness
• Positive McMurrary test

Imaging Studies

• X-rays
• MRI

Treatment

• NSAIDS
• Physical Therapy
• Arthtoscopy