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Q: I have a large sack-like swelling under my knees. The doctor says it's bursitis. I've been putting cold and hot packs on then without any relief. Would a vitamin B-12 shot help?

-- E.B., Gettysburg, S.D.

A: I'm amazed at how many people think that B-12 shots are a medical answer to such a wide variety of problems. I'm also concerned how many doctors give B-12 shots to patients on a regular basis without determining that the person has a B-12 deficiency.

My short answer to your question is that I don't think B-12 would help. My best guess, with your limited description, is that you have what are called Baker's cysts. They are a form of bursitis or inflammation of a bursa.

A bursa is a flat, fluid-filled sac that acts as a cushion to to reduce friction in areas where skin, muscles, tendons and ligaments rub over bones. In doing so, they make normal joint movements a lot easier.

If a bursa becomes inflamed as a result of overuse, injury or infection, or because of arthritis or gout, it may fill with fluid and become painful to the touch. This condition is known as bursitis. The shoulder is most susceptible to bursitis, but it is also seen in elbows, hips, knees and heels.

Chronic bursitis may come from previous bouts of acute bursitis or repeated injuries. Attacks of chronic bursitis may last from a few days to several weeks, and may come and go.

Because a swollen bursa can press against other structures such as nerves and blood vessels, or may even rupture, the standard treatment is to drain it. Draining can be easily done by aspiration, in which a needle is inserted through the skin into the bursa then the excess fluid is sucked out.

If the fluid in the Baker's cyst is infected (it rarely is), the pus must be removed by sucking it out through the needle, then antibiotics need to be given. Removal of the entire cyst would disrupt the protective effect this bursa has and cause greater problems later.

Most bursitis and the subsequent formation of Baker's cysts are caused by trauma to the local area. At the time of the trauma, in this case to the knees, you should first apply cold for up to 30 minutes, then later apply heat. Immobilization of the joint and elevation when practical is also beneficial.

Taking non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen will not only help reduce pain, it will also help reduce inflammation. In a few cases, local injections of steroids may improve the situation, but should not be done more than two or three times.

For long-term improvement and prevention of future injuries, physical therapy to restore the joint's function and exercises to help strengthen weakened muscles are also important.

It's also possible that poor posture, ill-fitting shoes or misalignment of the bones could make your bursitis keep recurring.

Write to Dr. Allen Douma in care of Tribune Media Services, 435 N. Michigan Ave., Suite 1400, Chicago, Ill. 60611; or contact him at This column is not intended to take the place of consultation with a health-care provider.

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