Knee bursitis is inflammation of a bursa located near your knee joint. A bursa is a small fluid-filled, pad-like sac that reduces friction and cushions pressure points between your bones and the tendons and muscles near your joints.
Each of your knees has 11 bursae. While any of these bursae can become inflamed, knee bursitis most commonly occurs over the kneecap or on the inner side of your knee below the joint.
Knee bursitis causes pain and can limit your mobility. Treatment for knee bursitis often includes a combination of self-care practices and doctor-administered treatments to alleviate pain and inflammation.
Knee bursitis signs and symptoms may vary, depending on which bursa is affected and what precisely is causing the inflammation. In general, the affected portion of your knee may:
Feel warm to your touch
Appear swollen or feel squishy to your touch
Be painful or tender when you move or put pressure on it
A sharp blow to the knee can cause symptoms to appear rapidly. But most cases of knee bursitis result from repetitive injuries — sustained in jobs that require a lot of kneeling — so symptoms usually begin gradually and may worsen over time.