πίσω
COPYRIGHT © by Michaelidou Maria
Dr. Maria Michailidou
BAKER’S CYST
A Baker's cyst, also known as a popliteal cyst, is a benign swelling of the semimembranous or more rarely some other synovial bursa found behind the knee joint. It is named after the surgeon who first described it, William Morrant Baker (1838–1896). This is not a "true" cyst, as an open communication with the synovial sac is often maintained
Cause
Ιn adults, Baker's cysts usually arise from almost any form of knee arthritis (e.g. rheumatoid arthritis) or cartilage (particularly a meniscus) tear. Baker's cysts can also be rarely assocaited with Lyme disease. Baker's cysts in children do not point to underlying joint disease. Baker's cysts arise between the tendons of the medial head of the gastrocnemius and the semimembranosus muscles. They are posterior to the medial femoral condyle.
The synovial sac of the knee joint can, under certain circumstances, produce a posterior bulge, into the popliteal space, the space behind the knee. When this bulge becomes large enough, it becomes palpable and cystic. Most Baker's cysts maintain this direct communication with the synovial cavity of the knee, but sometimes, the new cyst pinches off. A Baker's cyst can rupture and produce acute pain behind the knee and in the calf and swelling of the calf muscles.
Diagnosis
Diagnosis is by examination. A baker's cyst is easier to see from behind with the patient standing with knees fully extended. It is most easily palpated (felt) with the knee partially flexed. Diagnosis is confirmed by ultrasonography, although if needed and there is no suspicion of a popliteal artery aneurysm then aspiration of synovial fluid from the cyst may be undertaken with care. An MRI image can reveal presence of a Baker's cyst.
A burst cyst can cause calf pain, swelling and redness that may mimic thrombophlebitis
or a potentially life-
Treatment
Baker's cysts usually require no treatment unless they are symptomatic. It is very rare that the symptoms are actually coming from the cyst. In most cases, there is another disorder in the knee (arthritis, meniscal tear, etc) that is causing the problem. Initial treatment should be directed at correcting the source of the increased fluid production. Often rest and leg elevation are all that is needed. If necessary, the cyst can be aspirated to reduce its size, then injected with a corticosteroid to reduce inflammation. Surgical excision is reserved for cysts that cause a great amount of discomfort to the patient. A ruptured cyst is treated with rest, leg elevation, and injection of a corticosteroid into the knee. Recently, prolotherapy has shown encouraging results as an effective way to treat Baker's cysts and other types of musculoskeletal conditions.
Baker's cysts in children, unlike in older people, nearly always disappear with time, and rarely require excision.