Knee bursitis is inflammation of a small fluid-filled sac (bursa) situated near the joint. It causes pain and can limit mobility.
A sharp blow to the knee can cause symptoms to appear. most cases result from friction and irritation of the bursa that occurs in occupations which require frequent kneeling on hard surfaces. Sports can also be a cause of this condition.
Bursitis often improves over time. Sometimes aspiration or surgery might be necessary.