A bursa is a thin sack filled with the body’s own natural lubricating fluid. This slippery sack allows different tissues such as muscle, tendon, and skin slide over bony surfaces without friction. These bursa are normally very thin (like a plastic bag with the air sucked out of it), but they are a potential space that can become swollen and inflamed. This is what is known as bursitis.
The primary concern with prepatellar bursitis is that the bursa can often become infected. In fact, of all the common types of bursitis, prepatellar bursitis is the most commonly infected type. Usually, the infection comes from some penetration through the skin which may be a scrape, an abrasion, or a deep cut. The most common type of infected prepatellar bursitis is a Staph infection.
Causes
Pressure from constant kneeling on the job is the traditional cause. Carpet laying, plumbing, gardening, and agricultural jobs may be risks. It can also be caused by a blow to the kneecap during sports or smacking it during a fall.
Symptoms
The symptoms of prepatellar bursitis include:
Swelling over the kneecap Limited range of motion of the knee Painful movement of the knee Redness on the front of the knee
The swelling of knee bursitis is within the bursa, not the knee joint itself. People often call any swelling of the knee joint “water on the knee,” but it is important to differentiate fluid accumulation within the bursa versus fluid accumulation within the knee joint.
Treatment
Treatment of prepatellar bursitis begins with avoiding the aggravating activity. Other commonly used treatments include anti-inflammatory medications, ice application, and compression wraps. When there is significant accumulation of fluid in the bursa, consideration can be given to remove the fluid by draining the bursa with a needle and syringe.
If the fluid is drained from the bursa, analysis of this fluid can be performed if there is a question of infection. If there is no concern for infection, often a cortisone injection will also be administered to hopefully prevent the fluid from coming back.
Patients who do have an infection of their bursa require additional treatment. There is debate about the best treatment, and it likely depends on the severity of the infection and the individual patient to know the best treatment. Options may include oral antibiotic treatment, intravenous antibiotics, or surgery to remove the infected bursa. Usually if an infection is detected quickly, simple treatments will begin, whereas more aggressive, advanced infections may require a surgical procedure to clean the infection to prevent it from spreading.
