A bursa is a fluid filled sac that functions as a gliding surface to reduce friction. It allows tendons to slide around major joint areas. When the sacs become inflamed it is called Bursitis. Commonly bursitis is caused by overuse or trauma.
There are three major bursa about the knee. Above the kneecap is the prepatellar bursa and usually becomes inflamed by direct trauma such as kneeling or kicking. This is commonly seen in people working on their knees such as carpet finishers or carpet layers. It was seen in earlier times when people would scrub their floors on their hands and knees so it was called “Housemaids Knee”. The symptoms would be redness swelling and warmth over the bursa. The knee would flex normally as it was not involved in bursitis.
The second knee bursa is located below the kneecap before the shinbone. It is called the infrapatellar bursa. The common cause of bursitis here is a jumping injury and it is names “Jumpers Knee”. The symptoms would be the same.
The third bursa is on the inner side of the knee and is called the anserine bursa. This bursa commonly is inflamed in respond stress such as being over weight.
Treatment of bursitis is ice, rest anti-inflammatory medications and sometimes injections of cortisone.
Rare are infectious causes of bursitis and these are treated with aspiration antibiotics and sometimes surgery.