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.
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.
Baker's cyst
Hello!
I am writing to sing your praises! I am not kidding. I was first diagnosed with a Baker’s cyst approximately three months ago. The pain became increasingly intense, so I finally made an appointment with an orthopedic surgeon. He explained that the cyst was most likely the result from a torn meniscus and that I would require surgery. In the meantime, my patches I had ordered arrived, so I had used five patches by the time I returned to the orthopedic surgeon for the follow up for my MTI. He did NOT find a torn meniscus and was amazed at how much more range of motion I had in my knee. He agreed “whatever is working, keep it up!”
I am 62 years old, quite active, practice yoga and exercise daily. I am currently planning to swim with the dolphins with my grandchildren next month instead of planning surgery, physical therapy, etc. THANK YOU!!
Baker's cyst
Hi,
I just send you another order of patches.
It helps me a lot especially to sleep because I am always in pain with my bakers’cyst so I do not want to run out of patches.
Thank You
Baker's cyst
Dear Toky,
Thank you for the OSMO patches.
I’m seeing a big reduction in the swelling and pain.
Thanks
Baker's cyst
Hi Toky,
Received the patches yesterday.
Thanks to you from the old lady for whom I keep purchasing these patches from you. She says these patches are really working wonders on her leg.
Best regards
Baker's Cyst
I’ve had bakers cyst under my knee cap for 5 years and I’ve been in constant agony and haven’t been able to bend my knee for 5 years.
All my doctor could come up with was sticking needles under my knee cap, but 3 days on patches and it’s amazing swelling has almost gone, pain is a lot less and for the first time I will be able to get on floor and play with my grandson this christmas.
Thank you it means so much to me.
Baker's cyst
Ok, I have an arthritic knee from playing American football and having an operation when I was 18. Going to a doctor to have it drained would cost me well over $220. I know that I will need to get this knee replaced sometime in the near future and you can only do this one time, so it is in my best interest to find a way to prolong the knee replacement.
I tried the OSMO Patch about 1-2 years ago, thinking it may be a gimmick, and it was no gimmick because it works. The pressure on my knee is lessened by morning and I can move around a lot better. I’m health conscious, watch what I eat, go to the gym 3-4 times a week and of course I work. It is important to be open to alternatives instead of the ‘give me a pill’ attitude that most of the public has. As individuals, we have to realize that we, not someone else, are the most interested in our own health.
Thank you
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!!!
Real accounts by real people. Hear what they have to say!
Hello,
I have used your patches for my baker’s cyst. I started a while back, stopped, and found the cyst increased in size.
I have now been using it again for 1 week and the discomfort of it is considerably reduced.
The patches give such good relief
I hurt my knee quite severely when out bushwalking in the Mt Mitchell National Park. I hadn’t been doing much strenuous walking and on the way down I got a nasty pain in my knee.
My doctor told me I had a Bakers Cyst on the knee. I found your website and the OSMO Patch sounded like a good idea and I ordered it. It arrived within seven days of placing the order and it relieved the pain overnight. I find if I use the patches for three nights (until it’s dry) I have no pain for several weeks.
I like it because it’s a natural non-invasive treatment and above all it works. I don’t like taking pills and anti-inflammatory medication and prefer natural methods over drugs.
Back in July I hurt my knee, and later formed a baker’s cyst…it got so bad that I could not bend my knee without a lot of pain.
I found your website and ordered a ten pack… used them, and in no time the swelling was down, but not gone. I could bend my knee and walk normal…something I have not done since July. I ordered your patches again… Because from the time I used my last patch, til I got my order, some of the swelling and stiffness came back… started using them again… and just like before the cyst is going down… without needles! Love that.
I just want to say thank you!, my knee is almost back to normal… the best thing I have ever used.
Hello.
The patches arrived. Thank you very much.
I have used 3 and they are very good. They certainly draw the liquid away from the back of my knee.
