Everyone has a bursa. In fact, we have many bursae throughout the body. They are the fluid-filled sacs located in and around our joints which help reduce friction when we bend those joints.
One of these slippery sacs, called the prepatellar bursa, is located conveniently on the outside of our kneecap (patella). Its position allows the kneecap to glide freely underneath the skin as we bend our knees. Unfortunately, its convenient location also makes it an easy target for injury, by either sudden trauma or repeated damage over a period of time.
When injured by sudden trauma, such as a direct blow to the knee, the injured bursa sac fills rapidly, like a balloon, with blood and/or synovial fluid. Over the course of two or three weeks, as the body reabsorbs the blood and the injury heals, the resulting inflammatory reaction causes swelling at the front of the knee.
Prepatellar bursitis can also result from repeated mini-traumas over a longer period of time and tends to be fairly common among individuals whose professions require frequent kneeling (which is why many people refer to it as housemaid’s knee, coal miner’s knee, rug cutter’s knee, nun’s knee, etc). The inflammatory reaction and subsequent pain and swelling will develop more slowly in these instances.
Prepatellar bursitis can typically be treated at home with R.I.C.E. (rest, ice, compression wraps, and elevation) and an over-the-counter anti-inflammatory such as ibuprofen. It should improve within two or three weeks.
In some cases, however, you may need to seek treatment by an orthopedic doctor. Symptoms for more severe cases include (but are not necessarily limited to):
Significant accumulation of fluid in the bursa
Pain and swelling for longer than 2 or 3 weeks
Limited range of motion
Redness that spreads around the knee*
Fever, chills, or night sweats*
And, of course, don’t hesitate to call your doctor if you are concerned about symptoms other than those listed above.
For severe cases, the doctor may consider surgical drainage, therapeutic injection, or complete removal of the prepatellar bursa (don’t worry, you’ll grow a new one).
*These symptoms indicate a possible infection and require urgent consultation with a physician.