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.
I received my patches and after wearing them two nights, my baker’s cyst is almost gone – and no more pain!
Thank you, thank you, thank you!
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Baker's cyst
Hello!
I wanted to write to let you know that I truly feel that a combination of your OSMO patches and infrared laser treatments on my knee have nearly cured my knee. I had a probable torn meniscus, and had developed a baker’s cyst behind the knee from the injury.
I am a very active 52 year old female who plays softball and ice hockey. I work full time as a middle school teacher also. I am currently training for the 3 day, 60 mile Susan G. Komen Walk for the Cure for Breast Cancer. I rarely am sitting down. I ordered 10 of your patches and have used 9 over the last 3 months. I hadn’t had any swelling return until today.
I am confidently placing another order, because your patches truly do work. Thank you! I can’t wait to get my next order!
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Baker's cyst
Hi there!
My mother had 20 patches, it made a lot of difference for her knee, she got a big relief out of it, she started bending her knee now after many years,
With best regards
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Baker's Cyst
I don’t know how to submit a testimonial, so I am just sending you a thank-you note.
I had a baker’s cyst over a year ago, and with time (months), it diminished. Doctor said he did not recommend anything but the R.I.C.E. therapy (which helped some). Thought it was a one and done, but no. Fast forward a year and after “dancing” on a ladder to paint the garage, I remember a knee twinge and within ten days, another swelling in the back and very painful.
A neighbor mentioned she had the same issue and used your patch. Had an extra one for me to try. All I can say is, “Wow” and “Thank you.” In one use, I can walk more comfortably and not cringe every time I sit down and stand up. I’ve ordered more.
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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.
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Baker's cyst
Hi, just a quick note that I feel I needed to write about the OSMO Patches. In September I tripped over while running and fell on my knee which left me with a fractured bone at the back of my knee which in turn ruptured my cruciate ligament. Although back on track now after various braces, crutches and hydrotherapy plus physiotherapy, it seemed I had gained a cyst at the back of my knee. This tight swelling really hindered my ability to improve and I looked to the internet for answers-where I found your advert
Although I had never heard of your product and neither had my physiotherapist, I decided to give them a try as they wouldn’t hurt even if they didn’t help. The day I woke up after the first patch I was really surprised. I didn’t say anything to my husband because I didn’t want to jinx the feeling I had! The tightness had lessened dramatically which meant I could walk as soon as I got up, not the usual stretch and wait for it to get going!! My physio noticed a difference the next visit as it was the first time I could get my leg flat and flex my foot slightly. The reduction in swelling and tightness was brilliant. Although I have only used two my leg has improved so much and it helps that I can exercise properly to strengthen my muscles.
Thanks for your help I am no longer sceptical about the patches-will be ordering more in the future!
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Baker's cyst
Hi Jasmine,
I received the patches on SATURDAY and this is working fine.
THANKS
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Baker's Cyst
Danniel Jacques has made the world a better place for those of us that end up with too much synovial fluid – thank you very much!!!
I had my first Bakers Cyst about 10 years ago and unfortunately the left over patches are a bit past the used by date to treat the one I developed Tuesday night at tennis. Can’t wait for my order to arrive.
My son is a Dr in London and I asked if he had had much to do with bakers Cysts and he said yes = crazy sportsman too who’s had far too many serious injuries. He said go and see the local sports med doc but I said I will be using OSMO Patches again.
Real accounts by real people. Hear what they have to say!
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I have used the patches for a week now and am happy to say that the swelling of my bakers cyst has reduced to the point of very little pain now.
I am so pleased that I will tell my consultant about the patches, and my daughter who is a holistic nutritionist. She will recommend them to her patients as needed.
I have ordered another 20 patches – just in case!!
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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.
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To whom it may concern,
Got my patches yesterday and skeptically put one on last night.
I woke up this morning astonished, pain gone, flexibility back.
Don’t know how you discovered this but thank you. I will be ordering more as needed.
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Toky,
I got my patches. I used it for 12 hrs last night.