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Baker Cysts

(Baker's Cysts; Popliteal Cysts)


Joseph J. Biundo

, MD, Tulane Medical Center

Last full review/revision Feb 2020| Content last modified Feb 2020
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Baker cysts are small sacs filled with joint (synovial) fluid that form in an extension of the joint capsule behind the knee.

A rapid increase in the amount and pressure of fluid within the cyst can cause it to rupture. The fluid released from the cyst can cause the surrounding tissues to become inflamed, resulting in symptoms that may mimic those of a blood clot in the calf (deep vein thrombosis [DVT] Deep Vein Thrombosis (DVT) Deep vein thrombosis is the formation of blood clots (thrombi) in the deep veins, usually in the legs. Blood clots may form in veins if the vein is injured, a disorder causes the blood to clot... read more Deep Vein Thrombosis (DVT) ). Moreover, a bulging or ruptured Baker cyst can rarely actually cause thrombophlebitis in the popliteal vein (which is located behind the knee) by pressing on the vein.

Diagnosis of Baker Cysts

Treatment of Baker Cysts

  • Joint aspiration and corticosteroid injection

  • Sometimes surgical removal of the cyst

  • For ruptured cysts, pain relievers

When arthritis causes chronic knee swelling, the doctor may need to remove the fluid with a needle (a procedure called joint aspiration Joint aspiration (arthrocentesis) A doctor can often diagnose a musculoskeletal disorder based on the history and the results of a physical examination. Laboratory tests, imaging tests, or other diagnostic procedures are sometimes... read more Joint aspiration (arthrocentesis) ) and inject a long-acting corticosteroid (such as triamcinolone acetonide) to reduce the size of the cyst or prevent the formation of a Baker cyst. Removing the cyst surgically is an alternative if other treatments are not effective.

If the cyst has ruptured, the pain is treated with a nonsteroidal anti-inflammatory drug Nonsteroidal Anti-Inflammatory Drugs In some cases, treating the underlying disorder eliminates or minimizes the pain. For example, setting a broken bone in a cast or giving antibiotics for an infected joint helps reduce pain.... read more (NSAID) or another pain reliever if NSAIDs cannot be taken. If the ruptured cyst causes thrombophlebitis in the popliteal vein, treatment is bed rest, elevation of the leg, warm compresses, and anticoagulants (such as warfarin).

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