What Is a Baker’s Cyst?
A Baker’s cyst is a fluid-filled sac behind your knee. It often causes a bulge and a feeling of tightness. You might hear your doctor call it a popliteal cyst.
Baker’s cysts got their name from the doctor who first described them, a 19th-century surgeon named William Morrant Baker.
Baker’s Cyst Symptoms
Swelling is the most common symptom of a Baker's cyst. Other symptoms include:
Baker’s Cyst Causes
Causes of a Baker’s cyst may include:
- Swelling in the knee. This happens when the fluid that lubricates your knee joint increases. When pressure builds up, fluid squeezes into the back of the knee and creates the cyst.
- Arthritis. People with all forms of arthritis often have Baker’s cysts.
- Gout. This type of arthritis, which results from the buildup of uric acid in the blood, can lead to a Baker’s cyst.
- Knee injuries. Certain types of damage to your knee can lead to Baker’s cyst, such as a tear in the ligament that connects the thigh bone to the shin bone (anterior cruciate ligament, or ACL) or a tear in your meniscus, which is the pad of cartilage that cushions your knee joint. A sports-related injury or any other blow to the knee can also cause a Baker's cyst.
Baker’s Cyst Diagnosis
See your doctor if you have any of the symptoms listed above and they’re causing problems.
They’ll examine you to rule out more serious conditions, such as a blood clot (deep vein thrombosis).
They may also order an imaging test to get a better look, such as:
- Ultrasound
- MRI
- X-ray
Baker’s cyst ultrasound
When your doctor uses an ultrasound to look at your knee more closely, they take a probe that emits sound waves and glide it across the skin of your knee. The sound waves bounce off the structures inside your knee and create an image. This image shows your doctor the lump in greater detail and helps them see if it’s solid or filled with fluid. A solid mass isn’t a Baker’s cyst.
Baker’s Cyst Treatment
You may not need any treatment for a Baker’s cyst. They aren’t dangerous and tend to go away on their own. But there are things you can do at home to ease your pain and make yourself more comfortable:
Keep it cold. Apply a cold pack to the affected area. It’ll help keep the swelling down. A compression wrap might also help.
Take medication. To ease pain and inflammation, take an over-the-counter medication such as ibuprofen.
Rest your leg. Keep it raised above your heart level when possible. This will keep down swelling. You may want to use a compression bandage and a cane or crutch when you walk to keep pressure off your leg.
If these at-home treatments don’t work, see your doctor. They may suggest:
Steroids. These can help lessen inflammation.
Exercise. A physical therapist can teach you gentle exercises to help improve your range of motion and strengthening moves to build up the muscles around your knee. This could ease your symptoms.
Aspiration. Your doctor can drain the cyst. They’ll likely do it with the aid of an ultrasound. This treatment may not work if your case is severe.
Surgery. If you’re in serious pain or if the cyst makes it hard for you to move your knee, surgery might be an option. But it’ll work only if your doctor also treats the issue that caused the Baker’s cyst, such as arthritis.
If your leg turns red or darker and starts to swell, see your doctor right away. This could mean your Baker’s cyst has burst. You may notice fluid leaking out. Your body will eventually absorb the extra fluid in your leg after a few weeks.
Baker’s Cyst Prevention
Your best bet to avoid Baker's cysts is to prevent knee injuries in the first place. Wear the right shoes when you work out. Be sure to warm up before you exercise. And if you do get a knee injury, take care of it right away. See your doctor if it doesn’t get better.
Baker’s Cyst Complications
As a Baker’s cyst grows in size, it can cause problems, especially if it grows quickly. A large Baker’s cyst can press on the surrounding blood vessels or nerves, causing swelling, numbness, and pain.
Baker’s cyst rupture
Sometimes, if the pressure in your cyst increases quickly or gets too high, it can burst (rupture). This can cause pain, swelling, and bruising on the back of your knee and calf. The pain might get worse when you fully extend your knee or when you’re active. If this happens, it might be confused with a deep vein thrombosis.
Thrombophlebitis
The symptoms of a ruptured Baker’s cyst can feel like those of a blood clot in your leg, a condition called thrombophlebitis. This can be serious. See your doctor to be sure it’s not. Rarely, a bulging or ruptured Baker’s cyst can cause these blood clots, so it’s important to be checked out.
Edema
When a Baker’s cyst presses on the surrounding vessels, it blocks the flow of blood and fluid in and out of the area. This causes swelling (edema). If the cyst grows large enough to affect your calf muscle, you may notice swelling in your ankles, feet, and toes.
Compartment syndrome
A compartment is the medical term for a group of muscles, nerves, and blood vessels. Compartment syndrome is the buildup of pressure around this area. This pressure keeps blood, oxygen, and nutrients from getting to the tissues in the area. It’s very painful and can make your calf feel full, firm, and hard to stretch.
When to Contact Your Doctor
Your doctor needs to know if you have a lump on your leg that looks like a Baker’s cyst so they can check it out in detail. You should call your doctor right away if you have symptoms alongside your cyst that could mean a blood clot has formed in your leg. Sudden swelling, warmth, redness, and pain are all potential signs of a blood clot.
Takeaways
A Baker’s cyst is a fluid-filled sac behind the knee that can cause swelling, pain, stiffness, or tightness. But sometimes, it may not cause any symptoms at all. You can get it because of knee conditions such as arthritis, injury, or gout. Baker’s cysts often grow large, or rarely, burst, causing complications such as swelling, numbness, or even symptoms resembling those of a blood clot, requiring medical attention. Treatment includes at-home remedies, such as rest and cold packs, and medical treatment, such as draining the cyst, physical therapy, or surgery, depending on how bad your cyst is and what caused it.
Baker’s Cyst FAQs
What is the best way to get rid of a Baker’s cyst?
Sometimes, a Baker’s cyst will go away on its own and you don’t need to do anything. But a large or painful cyst may need treatment. Your doctor may drain it with a needle or may remove fluid from the cyst while doing surgery to repair knee injuries you have alongside your cyst. In rare cases, you may need surgery to remove the cyst.
What triggers a Baker’s cyst?
A common cause of Baker’s cysts is arthritis, especially rheumatoid arthritis, osteoarthritis, and gout. Knee injuries are another risk factor for Baker’s cyst, especially tears in your anterior cruciate ligament (ACL) or meniscus. Sometimes, a blow to the knee during sports or another activity can cause a Baker’s cyst.
How should I sleep with a Baker’s cyst?
There’s no special position you need to sleep in if you have a Baker’s cyst. The risk of rupturing your cyst while lying down — even on your back — is slim to none. If your cyst is disrupting your sleep, talk to your doctor about how to ease your discomfort.
What happens if a Baker’s cyst is left untreated?
While it’s possible for your Baker’s cyst to go away on its own with no treatment, in some cases you can have complications from it. A Baker’s cyst that grows large can press on vessels, nerves, and tissues around the knee and cause swelling, pain, and numbness. Rarely, a Baker’s cyst can burst or cause a blood clot to form, which needs immediate medical care.
What is the best exercise for a Baker’s cyst?
When you have a Baker’s cyst, you should reduce physical activity to give your knee a chance to rest and recover. Avoid exercises that caused your injury, if that’s how you got your Baker’s cyst. Your doctor can suggest low-impact exercise that will help you maintain your physical fitness as you recover. Elevate your leg when possible to help with swelling.
What should I not eat with a Baker’s cyst?
If arthritis is the cause of your Baker’s cyst, talk to your doctor about how an anti-inflammatory diet could help you. Diet can’t cure inflammation, but by prioritizing certain foods in your diet, you can help fight inflammation. Healthy oils, foods rich in omega-3 (such as fish), dark red and purple fruits like cherries, blueberries, blackberries, broccoli, vitamin-C-rich foods, and beans are all inflammation-friendly food choices.
