What is a Baker cyst?
A Baker cyst, also known as a popliteal cyst or synovial cyst, is a soft, fluid-filled lump that forms on the back of your knee. Like many diseases and disorders, this cyst is named after the doctor who first described it. In the mid-1800s, Dr. William Morrant Baker concluded that these popliteal cysts resulted from fluid flowing out from a damaged knee joint. When structures in or around the joint are damaged, your knee produces extra fluid that can only flow one way so it forms a cyst on the back of your knee.
Symptoms and Causes
What causes a Baker cyst?
A Baker cyst is the result of joint damage that causes swelling in the knee. Examples of damage can include:
- Arthritis (osteoarthritis or rheumatoid).
- Direct damage to the knee (meniscus tear or ligament tear).
What are the symptoms of a Baker cyst?
Sometimes you’ll feel no pain at all, or only a slight pain with a Baker cyst. You may only have knee pain from the initial damage that caused the Baker cyst, but not the lump itself. Any strain can cause this lump or your knee to swell in size. When the knee or cyst swells, this can increase your pain and limit how much you can move your knee.
Symptoms of a Baker cyst may include:
- A fluid-filled lump behind your knee.
- Stiffness of your knee.
- Limited range of motion and ability to bend your knee.
- Swelling of your knee and/or leg.
Sometimes, a Baker cyst can cause swelling and redness in your lower leg that can be similar to the symptoms of a blood clot. A blood clot is an emergency situation. If you are ever in doubt, reach out to your healthcare provider right away. Your provider can check out your symptoms and determine if it’s a Baker cyst or a blood clot.
Diagnosis and Tests
How is a Baker cyst diagnosed?
You need a professional medical exam to diagnose a Baker cyst. During your appointment, your healthcare provider may do several tests to both confirm the Baker cyst and figure out what might be causing it, including:
- Taking a medical history: Your healthcare provider will ask you about any previous injuries you may have had to your knee and go over your entire medical history.
- X-ray: This test won’t necessarily show the Baker cyst itself, but it can be used to see if you have arthritis in your knee. Arthritis is one of the possible causes of a Baker cyst.
- Magnetic resonance imaging (MRI) scans: An MRI uses magnetic waves instead of X-rays to show detailed images inside the body. This test can give your provider even more information about what might be causing the Baker cyst.
- Ultrasound: A simple and painless test, an ultrasound uses sound waves to determine if the lump is solid or fluid.
Management and Treatment
How is a Baker cyst treated?
Treatment of a Baker cyst usually starts with nonsurgical options. One time-honored method that sports doctors and orthopaedic surgeons have relied on for decades to soothe swelling from joint damage is the RICE method: Rest, Ice, Compression, Elevation.
Often, your healthcare provider will suggest that you start with a nonsurgical treatment of your Baker cyst. These are generally things you can do at home that can improve your symptoms.
Nonsurgical treatment options can include the RICE method:
- Resting your leg whenever possible.
- Applying ice to your knee.
- Using compression wraps on your knee to decrease the amount of joint swelling.
- Elevating your knee while you are resting.
Other nonsurgical treatment options for a Baker cyst can include:
- Taking an anti-inflammatory medication, such as ibuprofen.
- Maintaining a healthy body weight, which can help put less pressure on your joints.
- Avoiding activities that strain your knee. This includes avoiding high-impact sports like jogging.
- Using a crutch or cane when you walk.
- Getting a referral for physical therapy from your healthcare provider to help strengthen your knee and body.
Your healthcare provider may also give you a steroid injection. This involves cortisone being injected into your knee joint, which can reduce inflammation (swelling) and pain.
Even though surgery is rarely used to treat a Baker cyst, there are some cases where surgery might be recommended. Surgery may be used to repair the source of your knee damage.
Your provider might suggest a surgical option to you if:
- Your knee pain is severe.
- You’re unable to move your knee well (limited range of motion).
In many cases, your provider will treat the cause of your condition in order to fix your Baker cyst. This might involve surgery for a knee injury or to correct damage to your knee. In other cases, your provider might focus on the cyst itself. Surgical options for Baker cysts can include:
- Cyst draining: Your healthcare provider can drain the fluid out of the cyst with a needle.
- Arthroscopic knee surgery: This procedure can be used to both diagnose and correct knee damage. Your surgeon will make a small cut in your knee and insert a device called an arthroscope (a flexible tool with a camera on the end). This is also called knee scoping.
- Knee osteotomy: In this procedure, your surgeon cuts part of the bone in order to correct damage to your knee. This surgery can be an option for those with arthritis knee pain.
What will my recovery be like after knee surgery?
Recovery times can vary from person to person. What one person experiences when recovering from knee surgery may not be what you experience. Some tips to keep in mind as you recover can include:
- Avoiding strenuous activities.
- Keeping your knee propped up for a few days after surgery to decrease swelling or any pain you may feel.
- Taking all of your pain and antibiotic medications as instructed by your healthcare provider.
- Going to your follow-up appointment with your provider several days after your surgery.
- Doing physical therapy to continue strengthening your knee if it’s been suggested by your provider.
After surgery, you may feel a little tenderness and throbbing in your knee. Reach out to your provider if this, or any of pain, continues as you recover. You should be able to drive two weeks after your surgery. Talk to your provider about when you can do other activities.
Can there be complications if I don’t treat a Baker cyst?
Not all Baker cysts are treated. You might feel that the pain is mild and leave it alone. The cyst might go away on its own if it isn’t treated. But, there are other complications that can happen if a Baker cyst is left untreated, including:
- The pain gets worse.
- The cyst increases in size.
- The cyst bursts, causing bruising in your lower leg.
If the cyst doesn’t go away, reach out to your healthcare provider. It’s important to be sure it is a Baker cyst. This condition could be mistaken for something more serious like a tumor or artery aneurysm, which is a medical emergency.
Can a Baker cyst be prevented?
The best way to prevent a Baker cyst is to prevent knee injuries. A few ways you can prevent an injury to your knee include:
- Wearing proper footwear.
- Using the balls of your feet to turn instead of your knees.
- Warming up properly before you exercise and cooling down afterward.
- Stopping immediately when you get a knee injury. It’s important to ice, rest, wear a compression wrap and elevate your injury when it happens. Talk to your healthcare provider about any knee injuries to make sure you’re caring for them correctly.
Outlook / Prognosis
Can a Baker cyst go away on its own?
It’s possible for the Baker cyst to go away on its own. When the cyst bursts under your skin, the fluid is absorbed back into your body. However, it’s often best to treat the source of the knee problem to get rid of the Baker cyst — and keep it from coming back again.
A note from Cleveland Clinic
If you notice that you have a lump on the back of your knee, it’s usually a good idea to call your healthcare provider and get it checked out. A Baker cyst can sometimes go away on its own and it doesn’t always cause pain. However, it’s important to have the condition diagnosed by your healthcare provider to make sure it isn’t a more serious medical condition.
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