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 the joints.
Each knee 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 the knee below the joint.
Knee bursitis can be caused by frequent and sustained pressure, such as from kneeling. It can also be caused by a direct blow to the knee, frequent falls on the knee, bacterial infection of the bursa, or from complications from osteoarthritis, rheumatoid arthritis, or knee gout.
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 the knee may feel warm to the touch, appear swollen or feel “squishy,” or be painful and 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 so symptoms usually begin gradually and may worsen over time.
A doctor diagnoses knee tendon bursitis by examining the knee and reviewing medical history. Your doctor may order medical imaging tests, such as ultrasound or MRI scans to confirm the diagnosis.
Knee tendon bursitis is treated first with rest and non-steroidal anti-inflammatory medications to relieve pain. Physical therapy modalities such as ice, therapeutic ultrasound, and exercise can help relieve pain and restore functional movement. Muscle wasting is a concern from disuse of the knee, especially in older adults and people with obesity. If symptoms persist, injections of local anesthetics, corticosteroids, or both medications help to provide some immediate relief.