A Baker’s cyst, also known as a popliteal cyst, arises from the knee joint and causes a lump at the back of the knee. Generally, we confirm a diagnosis by seeing a Baker’s cyst on ultrasound. In addition, a baker’s cyst drainage is sometimes necessary to remove pressure from the back of the knee. But is a baker’s cyst drainage essential?
What is a Bakers cyst?
A Bakers cyst is a fluid-filled sac. It forms when excess knee fluid pushes the back part of the knee capsule outwards. This creates a sac of fluid called a cyst. This cyst is also called a ‘popliteal cyst’ as it forms in the popliteal area of the knee.
Causes
A Baker’s cyst forms due to excessive fluid build-up in the knee. Usually, excess fluid is produced in conditions such as osteoarthritis, rheumatoid arthritis, and a torn meniscus.
It is essential to ensure that the lump in the back of the knee is not due to other pathology. More serious conditions that can look like a simple cyst include tumours, blood clots, and swollen arteries (also called aneurysms). Imaging such as an ultrasound or MRI can spot a simple cyst from more severe causes.
What are the symptoms of a Baker’s cyst?
Often, a Bakers cyst is symptom-free. The only noticeable change is a palpable soft lump at the back of your knee. Sometimes, the cyst can become tight or painful, particularly when straightening the knee.
The cyst can increase or decrease in size depending on how much knee joint fluid is produced.
In some cases, the cyst might burst to produce redness, warmth, and swelling of the calf. A ruptured Bakers cyst is often confused with a blood clot. In cases of calf swelling, you must see your doctor to exclude a blood clot. Usually, a person will need an ultrasound or a blood test.
Bakers cyst vs. ganglion cyst: how to tell the difference
A ganglion cyst, or meniscal cyst, comes from a meniscal tear. These cysts form on the inside or the outside of the knee. However, the cyst can sometimes develop at the back of the knee and mimic a Bakers cyst. Generally, an ultrasound is helpful to determine whether the swelling at the back of the knee is a Bakers cyst or a meniscal cyst. For example, the picture below shows a deep ganglion cyst coming from the meniscus in the joint.
Can a baker’s cyst cause calf pain?
Generally, a Baker’s cyst does not cause calf pain. However, if the cyst becomes large, it can press on other structures, such as the muscles, tendons, and nerves. As a result, pain can move from the back of the knee into the calf.
However, it is unusual for even a large cyst to cause severe pain. Generally, we recommend an ultrasound or MRI scan to rule out other causes of pain, such as a tumour or blood vessel aneurysm. Overall, a Baker’s cyst on ultrasound is differentiated from other causes.
Baker’s cyst and rheumatoid arthritis: Is there a connection?
Yes. People with rheumatoid arthritis are more likely to develop more prominent and painful Baker’s cysts. In these rheumatoid cases, Baker’s cyst on ultrasound reveals significant complex fluid and active synovitis.
What to do for a Bakers cyst, including Bakers cyst drainage
Treatment options depend on the cause, but nearly all cases should be managed non-surgically.
These options include:
- ice to the swollen cyst and knee joint
- oral anti-inflammatory tablets
- compression of the knee joint using a compression bandage
- drainage of the cyst using a needle and syringe
- Treatment of the cause of the excess swelling. For example, treatment of arthritis with exercise therapy can reduce the swelling produced by the joint and, therefore, the size of the cyst.
Finally, surgery should be avoided unless the cyst fails to settle with simple treatments or becomes painful or bothersome. However, even after removal, the cyst can come back.
Baker’s cyst aspiration technique
A Bakers cyst drainage is appropriate for cysts that get more extensive or painful despite simple treatments. Getting imaging, such as an ultrasound, to confirm a simple cyst is vital. Also, ultrasound allows you to insert the needle in the right spot and drain the entire cyst. The needle is often inserted into the middle of the cyst to ensure most of the fluid is removed. A cortisone injection into the sac sometimes prevents the cyst from returning. In addition, if excess fluid is produced by arthritis or a torn meniscus, some doctors inject a small dose of cortisone into the joint simultaneously.
Infected Baker’s cyst: is it possible?
Infected Baker’s cyst is rare. Nevertheless, you must consider an infected Baker’s cyst if you develop swelling and pain at the back of the knee.
What happens when a Bakers cyst ruptures?
Sometimes, swelling in the Baker’s cyst increases and ruptures. So, fluid from the cyst leaks into the calf, causing swelling. Unfortunately, the cause of swelling is often misdiagnosed as a more serious blood clot. Therefore, an ultrasound must confirm a ruptured cyst and rule out a blood clot.
Thankfully, a baker’s cyst rupture is harmless and does not need special treatment apart from leg elevation and compression of the calf.
Ruptured Baker’s cyst vs. DVT
Often, it can be challenging to differentiate between these two conditions. For example, while a baker’s cyst is harmless, a DVT can be life-threatening. Generally, an ultrasound is an easy way to get an accurate diagnosis.
Other frequently asked questions about Baker’s cyst
Do you need to perform a Baker’s cyst drainage?
Generally no. If you perform a Baker’s cyst drainage, it ususally comes back. Drainage is advised for cosmetic reasons or if you develop pain or discomfort at the back of the knee. However, we recommend injecting your knee to reduce joint swelling and prevent a recurrence.
Should you have an injection into the joint if your Baker’s cyst is drained?
Yes. Often, the cause of a Baker’s cyst is excess fluid production by the knee joint. So, stopping further fluid production by the joint to prevent a recurrence makes sense. Options include cortisone, hyaluronic acid, or PRP, although cortisone is probably more effective.
Can a Baker’s cyst be removed?
We suggest you avoid surgical removal unless you’ve tried other treatments, including drainage and knee joint injection.
Final word from Sportdoctorlondon about Baker’s cyst on ultrasound
I suggest seeing your doctor if you’re unsure about a lump behind the knee. Ultrasound can easily confirm a Baker’s cyst and rule out other lumps. At Sportdoctorlondon, we establish a Baker’s cyst on ultrasound. We also use ultrasound to drain the cyst if needed. Finally, we may inject the knee joint simultaneously if there is excess joint fluid.
I have a cyst on the side of my knee. It was drained 15 years ago and it’s been pain free until a few months ago. Is this something you do?
If you have a cyst on the side of the knee, then I think the most likely cause is a meniscal cyst.
https://sportdoctorlondon.com/lump-on-the-side-of-knee/
Yes I perform these injections under ultrasound.
Hello Dr Masci
Two years ago I developed a baker’s cyst in both knees just a few months apart (MRI scan on both) and both cysts ruptured. One went away but the other never went away and is once again large and quite uncomfortable – stiff and achy. The NHS doctors said they don’t treat them, ever, but I’d like to swim and run again (not jogging) but just reclaim full movement. Would aspiration be a possibility now? Thanks Nadia
Hi Nadia, Yes it’s possible to treat now with aspiration. But as I outline in my blog, I recommend also treating excess fluid build up in the knee joint if you have this problem.
Lorenzo
Hello to the doctor and all those looking for answers, I have a bakers cyst at the back of my knee that began getting worse after my knee meniscusectomy in 2020. It appeared to be a couple centimeters, but it has grown to be about 3in now. My doctor wont drain it he says never let anyone put a needle in there, it could be attached to anything that can cause damage. But sometimes the nerve pain that starts on top of it down the side of my leg becomes unbearable. Do you agree with his response? and how can I help my self? Thank you.
Hi Karen, Nerve pain is an unusual symptom of a Baker’s cyst. I also don’t agree that draining the cyst will cause damage especially if done under ultrasound.
As a general rule, I’d drain the cyst if very large or causing symptoms. But I’d also inject the knee joint to stop the cyst from re-appearing.
I’d speak to your doctor again.
Lorenzo
I have Baker’s cyst. Sometimes I have difficulties to go down on my knees. Should I drain it or you would rather suggest some medication?
P.S. You are very sexy dr.Masci
Hi Mila,
Many thanks for your query. As I outlined in my blog, I only recommend drainage if the cyst becomes painful. Also, when draining the cyst, I also recommend injecting the knee joint (usually cortisone, hyaluronic acid or PRP), to reduce the chances of the cyst returning. Medication doesn’t usually help a Baker’s cyst.
I won’t comment on the second part of your email. lol
Lorenzo
I have been diagnosed with a bakers cyst & is very painful , it also has burst.
Would I be better off to let it take its course or have it drained
I suggest leaving it as a burst cyst will probably settle completely.
I’m in year three of a second cyst on the back of my knee. I have had it drained , gel shots, cortizone shots, physical therapy and now I’m beginning to get veins blocked from the cyst being so large. What can I do to get the doctors to help me. I work 13 hours a day and carrying 50 on cement floors does not help. But doctors won’t take me off work to heal.
I presume the cyst is a baker’s cyst. If the cyst is large, it can be difficult to manage. Yes, I think your work is a significant factor.
I am 70 years old and live in Southern Ontario. I have Osteoarthritis(OA) in both knees along with recurring Baker’s Cysts(BC) in both knees.
LEFT KNEE: An MRI confirmed my Left knee has no cartilage left. I was told I have severe OA in the Left Knee. The Left knee also has a large bi-lobed BC that was drained twice but keeps recurring and is causing me considerable pain and tightness that affects my range of motion. Until such time I decide I want, or can get a LEFT Total Knee Replacement(TKR), is it advisable to get the Left Knee BC drained again? I have also received one Cingal shot and then over six months later, I got a Cortisone shot in my Left Knee. Both shots helped lessen the pain for a few months. The effects of the Cortisone shot lasted about one month longer than the Cingal injection.
RIGHT KNEE: Then my R Knee became swollen over the kneecap. It was so painful, I could not walk. I went to the ER and they gave me a Cortisone injection and 7-10 days later the injection started helping. I’m waiting to be scheduled for an MRI of my Right Knee. The Right Knee BC drained on its own according to the recent Xrays and Ultrasound.
Other than a TKR of one or possibly both knees, what other non-surgical solutions exist, other than physio therapy, GLAD: D exercises for OA, weight loss, and orthobiologic knee injections, specifically Cingal and Cortisone, which I am already doing when the pain is intolerable.
How successful is Platelet Rich Plasma (PRP) with severe OA?
Would Stem Cell Therapy regrow knee cartilage in both my knees even if one knee, or possibly both have no cartilage left?
And is Stem Cell Therapy available in Canada?
If not, do you have any idea as to when it might be?
Or, the closest place I can go to get Stem Cell Therapy?
Unfortunately, we don’t have good options for severe osteoarthritis. The only option I would consider is a combined HA + PRP injection – but even then I would not be confident of a response. I would avoid stem cells – expensive and no evidence they work better than other injections.
https://sportdoctorlondon.com/hyaluronic-acid-prp/
can a bakers cyst make your arm swell and hurt
Hi Carla,
No Baker’s cyst is situated at the back of the knee so should not affect your arm. LM
I am 57 and was diagnosed with arthritis last year. I just had a large Baker’s cyst drained today and he said he could not get it all out because some was too thick. But, he didn’t say anything about injecting cortizone after it was drained so that it won’t come back. Is injecting it after drainage part of the process most doctors do? Should I ask him if he did?
Thanks
Generally, I inject cortisone (or other injectables) into the knee joint to prevent cyst recurrence.
LM
Hello I have fractured left Patella and now have a plaster on. My RIGHT leg has a lump behind the knee Could this be due to the extra force I am using to stand up I am on blood thinners now for months but I am worried about a blood clot being behind the right knee.
Hi Sam, The lump is almost certainly a Baker’s cyst, although you should see your doctor to ensure it is a cyst.
LM
Helpful info
Grazie
Guess for me there’s nothing to do. Just don’t like a lump on my body
Hi
I had a long career as an endurance athlete. Completed over 30 marathons, two 50-mile races, about 60 10km races and twelve Ironman triathlons.
Just returned from the doctor and ultrasound showed Bakers Cyst caused by arthritis behind right knee. I had arthroscopic surgery on both knees years ago when the procedure was in its infancy. For decades my knees have been amazing. Did all my Ironman races and many marathons after surgeries.
I have since retired from racing and was running three times a week for fitness when cyst appeared.
The doctor said my running days are over. I don’t know if I’m willing to accept that as there has been very little or no pain and I will be having it drained and cortisone shot on a week or so.
I guess my question for you is do I really have to give up running?
Even though I don’t race, it’s a big part of who I am. From what the doctor said the arthritis can progress to the point where I would need a knee replacement. If that’s the case, my thinking is that I might as well run for as long as I can.
If I can run pain free, why not. I don’t want to die in front of the tv living the lazy, sedentary lifestyle. I’m 73.
Hi Ray,
I disagree with your doctor’s advice. There is no evidence that running per see increases wear and tear in your knee. In fact, low-level running (which doesn’t cause pain) could be protective by keeping your weight under control and protecting you from diseases such as obesity and diabetes – which we know can make your arthritis worse. I answer the running question about half way into this blog :
https://sportdoctorlondon.com/no-cartilage-in-knee/
LM
I have a painful Bakers Cyst,making it difficult to walk.I am in my 80s,but quite agile.My Doctor said cortisone injections he will not reccomend
Hi Heather, you could aspirate the Baker’s cyst – but it will almost certainly reappear. I suggest an injection into the knee joint at the same time as the aspiration. Injection options are cortisone or hyaluronic acid.
https://sportdoctorlondon.com/knee-injections-for-arthritis/