Meniscal injuries: Cause, Diagnosis, Treatment

Meniscal injuries occur when the flexed knee is forced into rotation while extending. The meniscus gets trapped between the femur and the tibia, and the tear occurs when the knee joint is extended.

Most commonly injured meniscus is the medial one. This is because the medial meniscus is less mobile, hence it is easily trapped between the bones.

In young patients tears occur during some active sports like football or basketball. In older people they can occur during day to day normal activity (because of degeneration). In such cases the patient may even not notice the injury. Associated injuries of the ligaments and capsule are usually present.

Before reading further it would be a good idea to see the relevant Knee Anatomy(skip this if you have already done so).

Tears can be of two types

Longitudinal ones are more common. Posterior segment is most commonly involved.

Small tears do not cause locking. Extensive tears cause locking when the torn portion gets displaced into the intercondylar notch (center of the knee).

Radial tears are more common in the lateral meniscus.

Symptoms after meniscal injuries include are

locking of the knee jointsense of weakness or giving way may be feltmild swelling may be seenmuscle wasting may occur

History of locking and the ability to reproduce it or a click like feeling during examination, is quite helpful in diagnosis.

During examination the doctor will perform a few tests that will help him to arrive at a diagnosis. They include

McMurray testApley grinding test

In both these tests the doctor will manipulate your limb in varying degrees of flexion extension and at the same time applying a rotational force. He will try to elicit a click like sound. There may also be some pain.

Various diagnostic investigations for meniscal injuries include

Radiographs of the knee joint. The menisci are not seen on radiographs. Radiographs are useful to rule out other bone injuries and conditions.MRI and CT scans can diagnose a torn meniscus with reasonable accuracy.Arthroscopy of the knee joint. Direct visualization of the meniscus and the other structures within the knee joint can be done. Simultaneous treatment can be done if required.Treatment for meniscal injuries includes Lifestyle modificationImmobilization of the extremity in a plaster cast extending from the groin to the ankleSurgery

Lifestyle modification includes

restriction of activitymuscular rehabilitation

It is indicated in tears that are occasionally symptomatic.

Cast immobilization is indicated in

incomplete tears in a stable joint (without any associate injuries)stable vertical tears occurring in the periphery of the meniscus

Surgery is indicated in

all symptomatic tears that fail to heal by conservative methodsunstable tears that cause locking of the knee joint

Surgery includes

excision of the part of the meniscus that is causing symptomsrepair of tears located in the periphery of the meniscus

Complications after surgery include

hemarthrosis (collection of blood within the joint)synovitis (swelling and collection of fluid in the joint)deep vein thrombosis (clot formation in the veins of the leg)Reflex sympathetic dystrophy (a condition characterized by pain, redness, warmth and muscle wasting)

Hemarthrosis is prevented by cauterizing all the bleeding vessels after surgery. If it occurs them the blood is aspirated and the limb is rested in a splint.

Synovitis is prevented by gradual mobilization of the joint. If it occurs then treatment is by aspiration and immobilization in a splint.

Deep vein thrombosis is prevented by prophylaxis with anti-clotting drugs.

Reflex sympathetic dystrophy occurs due to over functioning of the sympathetic nerves. Treatment is by physical therapy, anti-inflammatory, medication and sympathetic blocks.

Doesn't removal of the part of meniscus affect the function of the knee joint?

Yes, excision of the meniscus results in the development of degenerative changes that are proportional to the amount of meniscus excised. Therefore excision of the meniscus is only advised when it is persistently producing symptoms. Only the minimum amount required for relief should be excised.

How long does it take to return to active sports after surgery?

It usually takes 3 to 4 months to return to active sports.

I hope you found the information on this page useful. If you have any query then you can ask me at the contact me page.

This page was last updated on 25th December 2008.

Other causes of knee pain include...

Knee Osteoarthritis

Knee Bursitis

Ligament Injury

Knee Fracture

Patella Fracture

Tibial Plateau Fracture

Osgood Schlatter Disease

Knee Anatomy

Knee Replacement Surgery

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