Plica Syndrome

The kneecap (patella) connects all the muscles in the thigh to the lower leg (tibia). When you bend your knee, the patella slides up and down along the front of your knee. Your upper leg (femur) has a U-shaped groove (patello-femoral groove or sulcus) to accommodate the moving kneecap. The patella along with the mucles of your thigh enables you to straighten your leg out.

To further reduce friction in the knee, the tissue of the synovium has extra folds called plicae. Normally, a plica is small and smooth but if it becomes irritated it grows red and thick, causing pain and inflammation. There are 4 plicae in the knee but only the one on the inner (medial) side seems to get plica syndrome. The medial plica runs from the lower end of the patella along the inner side of the knee and attaches to the lower end of the femur.

Several problems can affect the patella. These include a condition called plica syndrome, which is the name given to irritation of a plica. Women are reportedly effected by plica syndrome more often than men, however a reason has not been identified. The condition is a painful nuisance, however treatment is simple and effective.