What is Knee Bursitis?
Knee bursitis is a painful condition in which one or more of the three fluid-filled sacs called bursae that surround the knee joint become inflamed. The function of a bursa is to be a gliding surface that reduces friction between tissues in the body. In knee bursitis, the bursa that is most often affected is the prepatellar bursa, which is located at the tip of the knee over the kneecap. It can become inflamed when there is trauma to the front of the knee. People who kneel a lot, such as roofers, carpet layers, and housekeepers, are susceptible to knee bursitis.
A second bursa, called the infrapatellar bursa, is located just under the kneecap beneath the tendon that attaches the muscles in front of the thigh and the kneecap to the bone in front of the lower leg. It is commonly seen as the result of a jumping injury and involves inflammation of the nearby tendon.
A third bursa, the anserine bursa, is located on the lower inner side of the knee. It usually becomes inflamed in individuals who are obese and in middle-aged women.
Symptoms of Knee Bursitis
People who have knee bursitis experience varying degrees of stiffness, swelling, warmth, tenderness, and redness in the knee joint area. For patients who have involvement of the prepatellar bursa, the pain is typically worse when kneeling, although the condition can cause stiffness with pain when walking. The range of motion of the knee is usually not affected. Patients with knee bursitis that affects the anserine bursa experience pain in the inner knee when climbing or descending stairs.
Occasionally, knee bursitis that involves the prepatellar bursa becomes infected with bacteria because of a break or puncture in the skin. When this occurs, patients usually experience a fever along with their other symptoms.
Knee Bursitis Treatment
The choice of knee bursitis treatment depends on whether there is an infection. Aseptic (no infection) knee bursitis that affects any of the three bursae can be treated with RICE (Rest, Ice, Compression, Elevation), and anti-inflammatory and pain medications. If the bursitis is persistent, the doctor may remove any fluid from the bursa using a thin needle. Noninfected knee bursitis that affects the prepatellar or anserine bursa can also be treated with an injection of cortisone.
If you have infected (septic) knee bursitis of the prepatellar bursa, you will need to take antibiotics and to have the fluid removed. In some cases, surgical drainage and removal of an infected bursa is necessary.