Medial meniscus tears are the most common knee injury that is treated medically.  Medial meniscus injuries occur ten times more frequently than lateral meniscus injuries because of how it is attached to the tibia bone below it. 

Injuries to the medial and lateral meniscus both result when the knee is twisted while the foot is on the ground bearing the weight of the body.

When the injury first occurs, a tearing or popping sensation is felt followed by severe pain.  Pain is felt along the knee joint line.

Swelling may occur over hours and it is often worse the next day.  After a few days the knee joint may lock or feel unstable, and pain becomes worse with activity.

Increased pain is felt with twisting of the knees, squatting, going up stairs and inclines.