What Is It?

A meniscus is a disk-shaped piece of cartilage that acts as a shock absorber inside a joint. Each knee has one lateral meniscus under the outer knob of the thighbone and one medial meniscus under the inner knob of the thighbone. Each meniscus acts as a natural cushion between the thighbone (femur) and shinbone (tibia). . The two cushions prevent excess wear and tear inside the knee joint by keeping the ends of the two bones from rubbing together. Each meniscus also absorbs much of the shock of jumps and landings and helps to distribute joint fluid evenly to lubricate and nourish the knee.

In the United States, a torn meniscus is the most common reason for knee surgery; 850,000 operations for meniscal tears are performed in the U.S. each year. Looking to update the 1996 figure, and clinic visits aren’t as interesting as operations to me, I found this - there may be more reliable numbers elsewhere – reference is below. RS

Symptoms

The symptoms of a torn meniscus can include:

• Knee pain, usually on one side of your knee

• Tenderness at the side of the joint

• Knee swelling within the first 12 hours after injury

• A "locked" knee that can't be bent

• A knee that catches during movement, or can't be fully straightened

• A click, pop or grinding inside your knee when you move it

• A knee that buckles, gives way or feels generally weak