CausesBy Mayo Clinic staff
A lubricating fluid called synovial (sih-NO-vee-ul) fluid helps your leg swing smoothly and reduces friction between the moving parts of your knee.
But, sometimes the knee produces too much synovial fluid, resulting in buildup of fluid in an area on the back of your knee (popliteal bursa), causing a Baker's cyst. This can happen because of:
- Inflammation of the knee joint, such as occurs with various types of arthritis
- A knee injury, such as a cartilage tear
- Helfgott SM. Popliteal (Baker's) cyst. http://www.uptodate.com/index. Accessed June 27, 2012.
- Handy JR. Popliteal cysts in adults: A review. Seminars in Arthritis and Rheumatism. 2001;31:108.
- Knee problems. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Knee_Problems/. Accessed June 27, 2012.