Baker's Cyst Health Video

A Baker's cyst involves the swelling of the knee. Learn how to diagnose and treat a Baker's cyst in this medical video.

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Most common cause is tear of the medial meniscus
Expect pain in a mass on back of knee
Consider a needle aspiration of the cyst

About this Author

Joshua Hackel, M.D. specializes in the prevention, diagnosis, and conservative management of musculoskeletal injuries utilizing the latest medical techniques for anyone who is injured on the job or at home. Following his residency in 2003 in family practice at Columbus Regional Hospital in Columbus, Ga., Hackel accepted a fellowship at the American Sports Medicine Institute (ASMI) in primary care sports medicine under the direction of orthopedic surgeon Dr. James R. Andrews. Upon completion of the fellowship, he was invited to become a member of the Andrews Institute for Orthopedics and Sports Medicine in Gulf Breeze, Fla.

DR. JOSH HACKEL: A baker's cyst is an abnormal accumulation of fluid between the knee joint and the popliteal fossa in the back of the knee. This is a knee model. You can see here the back of the knee and the joint line and the posterior aspect of the knee joint. A baker's cyst is located between the medial head of the gastrocnemius tendon and the semimembranosus tendon typically at the level of the joint line or just below. The most common cause of a baker's cyst is a tear involving the medial meniscus creating an increase in synovial fluid that increases the pressure within the knee. The pressure is then released by the fluid, the synovial fluid, going into the popliteal bursa in the back of the knee. Patients can expect pain and a mass in the back of their knee. Sometimes the mass or cyst can rupture creating pain and numbness down the back of their calf. This is oftentimes mistaken for a DVT or deep venous thrombosis. Also you can consider a needle aspiration of the cyst to take out the fluid; however, the cyst can reaccumulate. A baker's cyst is diagnosed on physical exam. You will feel a mass in the posterior-medial aspect or the back inner side of the knee. X-rays can be taken to rule out any calcification. Sometimes you can see the cyst on X-ray. An MRI can also be obtained to rule out any neoplasm or other sinister pathology.