Prepatellar Bursitis

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.

A small lubricating sac (called the bursa) is located just in front of the patella. The prepatellar bursa enables the patella to move smoothly under the skin. Although the prepatellar bursa normally contains a small amount of fluid, it can fill with more fluid and swell if it becomes inflamed as a result of an injury.

Several problems can affect the patella. These include a condition called prepatellar bursitis, which is a painful inflammation of the bursa, or fluid-filled cushion, that sits in front of the patella. Triggered by an injury or infection, prepatellar bursitis can occur suddenly and clear up on its own, or become a chronic problem.