A Bakers cyst is a buildup of joint fluid behind the knee. It creates a tight bump behind your knee.

Joint fluid helps the knee move smoothly. A Bakers cyst develops when there is too much of this fluid. The extra joint fluid is pushed out to the back of the knee. Extra fluid may be caused by:

  • Arthritisosteoarthritis is the most common type associated with Bakers cysts
  • Cartilage tears, such as a torn meniscus
  • Injury or accidents
  • Infection in joint

In children, Bakers cyst may be related to a problem with the bursa. The bursa is a small fluid filled sac between the bone and soft tissue.

Bursa
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