What are Baker's Cysts? Causes & Symptoms Explained!
Last reviewed on 25 October 2025 by
Danniel Jacques
(B.Med.Sci UNSW)
What is a Baker’s Cyst?
A baker cyst is a painful condition which can be characterised by swelling in the back of the knee.
This swelling occurs due to inflammation in the synovial joint which encapsulates the knee resulting in the out-pouching of fluid into a little balloon type sac from the synovial lining.
When this condition develops, synovial fluid (which is normally contained in a tough capsule that encases the knee joint) collects in the baker’s cyst and bulges behind the knee.
This is also called a “popliteal cyst” as it directly affects the popliteal region of the knee (that shallow depression located behind the knee joints).
If left untreated it is possible for it to rupture. A ruptured baker’s cyst may then cause the collected synovial fluid to transfer and travel down the calf muscles of the legs. This can then trigger rapid swelling and discomfort of the leg which may then cause further complications.
What Causes a Baker’s Cyst?
Baker’s cysts are quite common and can be caused by nearly any joint-related inflammation. Some of the most common causes may include;
A micro tear in the knee’s meniscal cartilage
Repetitive stress injury.
Wear & tear in the knee (which is more common in older adults)
Injury to the anterior cruciate ligament of the knee (ACL injury)
Sports-related injury that affects the knee
The type of work that a person does may also make them more susceptible. This include jobs that involve being on your knees, such as a gardener or carpenter. Also such jobs that require long shifts without sitting or unusual weight loading through the knees such as nursing.
Symptoms may include visible swelling or protrusion on the back of the knee (which can be either with our without pain), constant and prolonged knee pain, and tightness at the back of the knee or simply a feeling of tenderness at the back of the knee.
If left untreated a baker’s cyst may actually rupture. A ruptured or burst baker’s cyst can cause a lot of pain and discomfort and can present very similarly as a blood clot as there will also often be calf related pain.
How to diagnose a baker’s cyst?
It is always best to visit a qualified medical professional if you suspect that you have either a baker’s cyst or feel that your baker’s cyst may have ruptured or burst.
Your doctor will likely require you to have an ultrasound which will be able to confirm a diagnosis of baker’s cyst and also importantly rule out or alert the doctor of any existence of a blood clot.
If there is an infection suspected then a blood test and maybe an aspiration of the synovial fluid may be required for testing and culturing. In some cases an x-ray and or MRI may also be required to rule out any co-exist conditions that may have contributed to the condition.
Real accounts by real people. Hear what they have to say!
Baker's cyst
Toky,
I got my patches. I used it for 12 hrs last night.
The patch was wet and my knee feels better.
Thanks
Garrett B
Arizona, United States
Baker's cyst
Dear Folks in Australia,
I have just placed my third order with you for your OSMO Patches because they do work and I am so impressed with how they work. No one here at my end has ever seen anything like your patches and I love telling people about them.
I suffer from a Baker’s Cyst and so far, this is the only thing that alleviates the swelling. As you say in your literature, it doesn’t really cure the Cyst but it does give it relief. Amazing!!!
Best wishes
Patty C
Michigan, United States
Knee Baker's Cysts and Meniscus tears
I’ve had knee problems for 3 decades and have had 4 surgeries due to an ACL tear and numerous Meniscus tears. Due to these problems, I’ve had a chronic problem with a Baker’s Cyst which I’ve been living with for years and the swelling has kept me in constant pain.
I definitely recommend the OSMO patches. They have given me substantial relief from the pain that I was experiencing. I’ve recommended the patches my Physical Therapist and he’s recommended them to his patients. I’ve also recommended the patches to my Surgeon and he is now recommending the patches in lieu of injections.
William M
California, United States
Baker's cyst
Thank you.
I never thought I would be able to walk without pain again.
Thanks to your product, I was pain free the day after I applied the first patch.
Marcia M
Indiana, United States
Baker's cyst on both knees
I have been meaning to write you for some time now and tell you how great the OSMO patches have worked for me.
I have had Baker’s cysts over the past 4 years on both knees. My Orthopedic Specialist drained them numerous times, plus gave me cortisone shots. Researching the topic one day, I discovered your website and hesitantly ordered the patches… they work amazingly. There is such a difference when I wake up in the morning.
The fluid is drawn out and mobility is greatly improved. I will probably need surgery one day to repair torn cartilage in my knees, but these are greatly helping me with the swelling/fluid buildup like nothing else has before.
Thank you for developing such a wonderful product and for the prompt and efficient service. They are really helping me.
Janet R
Georgia, United States
Bakers cyst on the knee
Hi,
I got the patches yesterday evening. I have had five knee operations on my right knee and have arthritis. I also have a baker’s cyst on the back of my knee and off to the front.
I tried it last night and I was surprised at the results and it actually took away some of the swelling. I work out every other day and I think these will help.
Thanks
Leo J
Alabama, United States
Bakers Cyst on the knee
Hello Toky,
4 more patches to go, and I can report great improvement!
I can bend the knee, the lump in the back is so much smaller, (by half?) I think. Not even thinking of a drain needle and cortisone shot at this point.
Thank you so much.
Judy
North Carolina, United States
Baker's cyst
Hello, Thanks very much…. This order is my second one…. I developed a Baker’s cyst (I think) behind my left knee, jumping up and down hard on a truckload of brush I was trying to compact…. I’m 67 years old, and the next morning, I had pain behind my knees, then a large egg behind […]
