Baker's Cyst (Popliteal Cyst)

A Baker's (popliteal) cyst is a fluid-filled cyst on the back of the knee.

• ABaker's cystis swelling caused by fluid from theknee jointprotruding to the back of the knee.
• Baker'scystsare common and can be caused by virtually any cause ofjoint swelling(arthritis).
• A Baker'scystmay not cause symptoms or be associated withknee painand/or tightness behind the knee, especially when the knee is extended or fully flexed.
• Baker's cysts can rupture and become complicated by the spread of fluid down the leg between the muscles of the calf (dissection).
• Baker's cysts can be treated with medications,joint aspirationandcortisone injection, and surgical operation, usually arthroscopic surgery.

A Baker'scystis swelling caused by fluid from the knee joint protruding to the back of the knee. The back of the knee is also referred to as the popliteal area the knee. A Baker's cyst is sometimes referred to as a popliteal cyst or aBaker cyst.

When an excess of knee joint fluid (synovitis) is compressed by the body weight between the bones of the knee joint, it can become trapped and separate from the joint to form the fluid-filled sac of a Baker's cyst. The name of the cyst is in memory of the physician who originally described the condition, the British surgeon William Morrant Baker (1839-1896).

Baker's cysts are not uncommon and can be caused by virtually any cause of joint swelling (arthritis). The excess joint fluid (synovial fluid) bulges to the back of the knee to form Baker's cyst. The most common type of arthritis associated with Baker's cysts isosteoarthritis, also calleddegenerative arthritis. Baker's cysts can occur in children with juvenile arthritis of the knee. Baker's cysts also can result from cartilage tears (such as atorn meniscus),rheumatoid arthritis, and other knee problems.

Risk factors for a Baker's cyst include atorn meniscus, knee arthritis (includingosteoarthritisandrheumatoid arthritis), and knee joint injury.

A Baker's cyst may cause no symptoms or be associated withknee painand/or tightness, andstiffnessbehind the knee, especially when the knee is extended or fully flexed. Baker's cysts are usually visible as a bulge behind the knee that is particularly noticeable on standing and when compared to the opposite uninvolved knee. They are generally soft and minimally tender. Sometimes there can be a mild decrease in the range of motion of the knee.

Baker's cysts can become complicated by the spread of fluid down the leg between the muscles of the calf (dissection). The cyst can rupture, leaking fluid down the inner leg to sometimes cause the appearance of a painless bruise under the inner ankle. Baker's cyst dissection and rupture are frequently associated with swelling of the leg and can mimicphlebitis的腿。贝克囊肿破裂通常作为原因的es rapid-onset swelling of the leg withbruisingaround the ankle.

Doctors who treat Baker's cysts include general primary care physicians, orthopedists, andrheumatologists.

Baker's cysts can be diagnosed by the doctor's examination and confirmed by imaging tests (eitherultrasound, injection of contrast dye into the knee followed by imaging, called an arthrogram, orMRIscan) if necessary. Health care professionals can rule out other causes of swelling behind the knee (includingdeep vein thrombosis, poplitealaneurysm, and neuroma) using these imaging tests.

Baker's cysts often resolve with aspiration (removal) of excess knee fluid in conjunction with a cortisone injection. Medications are sometimes given to relievepainand inflammation, includingover-the-counteranti-inflammatorydrugs.

When cartilage tears or other internal knee problems are associated, physical therapy or surgery can be the best treatment option. During a surgical operation (typically byarthroscopyusing an arthroscope), the surgeon can remove the swollen tissue (synovium) that leads to the cyst formation. This is most commonly done with arthroscopic surgery. Physical therapy is often done in the recovery period.

Recovery time depends on the form of treatment rendered. With medications or injections into the knee, recovery can be rapid, within days to weeks. If surgical repair is done, recovery generally takes one to three months.

Home remedies, prior to medical evaluation, includecoldapplications, resting, and avoiding overuse or injury to the involved knee.

Complications of a Baker's cyst include blood clotting in the involved leg, as well as rupture of the Baker's cyst, causing swelling andpainof the leg andbruisingdiscoloration of the ankle.

Depending on the cause of Baker's cyst, the outlook is generally very good. Baker's cysts caused by chronic arthritis can be prone to recur in the long term.

There is nopreventionfor a Baker's cyst except minimizing any underlying arthritis disease.