Meniscal Tears

What is the meniscus?

The meniscus is a “C-shaped” cushion pad in the knee between the thigh bone (femur) and the lower leg bone (tibia). It acts as a shock absorber and makes the motion of the knee smooth.

How is it injured?

• One way is as part of an injury. This is one of the injuries what can happen when a person injures his/her knee. Usually this is a twisting knee injury with the knee in a bent or flexed position, but can happen in a variety of ways.

• Another way is what happens when meniscal cartilage ages. Young meniscal cartilage is very flexible, like young rubber. As it gets older it becomes like old rubber that has been exposed to the air for years. It becomes hard, less flexible, more brittle and can develop cracks in it like the cracks that develop in old rubber. These cracks in older cartilage are called degenerative meniscal tears. These degenerative tears can occur with or without an injury.

What are the symptoms of a meniscal injury?

They can vary greatly. Symptoms include

• pain

• a feeling of giving way of the knee

• catching and locking

• swelling

How is it diagnosed?
A meniscal tear is provisionally diagnosed by a physical examination and the diagnosis may be supported by an MRI (magnetic resonance imaging). Ultimately it can only be diagnosed definitively by arthroscopy.

What about MRI?

An MRI (magnetic resonance image)  uses a magnetic field instead of x-rays to produce the image.

It allows you to see soft tissues as shadows of different densities. It allows you to see tissues that x-rays cannot show and is extremely useful especially in spines, shoulders, etc.

I frequently do not use MRI to deal with meniscal injuries. The reason is simple. MRI is not totally accurate in diagnosing meniscal tears. I have frequently seen cases where a tear was seen on MRI which on arthroscopy turned out not to be there and the opposite: no cartilage tear seen on MRI, but one found during arthroscopy.

The practical meaning of this is that if an MRI is done and shows a "cartilage tear" the result is that an arthroscopy needs to be done. If however an MRI is negative, but symptoms persist, an arthroscopy often still needs to be done because the MRI could be wrong. So the MRI does not change what needs to be done and at a significant cost.

It may be a waist to do it if it will not contribute usefully to your treatment.

It is however useful in diagnosing other injuries of  the knee such as a ligament rupture and does help  identifying underlying osteoarthritis.

How is a meniscal tear treated?
A very small percentage of meniscal tears may heal on their own within about 6 weeks. If symptoms continue, then it is unlikely that the meniscal injury will heal and arthroscopy is necessary.

Bucket Handle Tear of the Medial Meniscus

External Links

• Meniscal Injury and Knee Arthroscopy
• Meniscal Tears of the Knee and  arthroscopic surgery
• TORN CARTILAGE (MENISCUS)

• Malka orthopaedics- Meniscus injuries

• AAOS On-Line Service June 2002 Bulletin Meniscal tears

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