Baker’s cysts (also known as Baker cysts or popliteal cysts) are common in people with rheumatoid arthritis (RA). These fluid-filled sacs form behind the knee, producing swelling that may cause discomfort. The pain may worsen during activity or when the knee joint is fully extended.

There are several ways to manage Baker’s cysts, both at home and with medical treatment. In many cases, treating the underlying cause (in this case, rheumatoid arthritis) may provide relief. Rheumatology is the medical specialty for inflammatory or autoimmune diseases like RA. If you develop swelling behind your knee, talk to your rheumatologist or a healthcare provider. They will work with you to find the best ways of managing the cyst and any potential discomfort.

What Are Baker’s Cysts?

Like most joints in the body, the knee joint is a synovial joint, meaning it contains synovial fluid. This fluid is a slick liquid that lubricates the joint and reduces friction in the knee. When a joint isn’t in use, this synovial fluid is partially absorbed by the surrounding cartilage. When a joint is in motion, the synovial fluid is squeezed out of the cartilage, aiding in movement.

A Baker’s cyst forms when inflammation or injury causes the joint to produce too much synovial fluid. This fluid can accumulate in the knee and migrate in the back of your knee (called the popliteal bursa), and it can remain there causing a Baker’s cyst to develop.

A recent study found that slightly more than 15 percent of people with RA experience Baker’s cysts. The study also found that those with RA whose arthritis symptoms were limited to the knee joint were more likely to develop Baker’s cysts.

The condition is named after 19th-century surgeon William Morrant Baker who’s credited with first describing it. Baker’s cysts can also occur as the result of injury or other disease, including osteoarthritis.

What Are the Symptoms of Baker’s Cysts?

In many cases, Baker’s cysts don’t cause any symptoms. If you do experience symptoms, you may feel stiffness in the knee joint and swelling, tightness, or pain behind your knee that may worsen when your leg is straightened and go away when your knee is bent. Note that some of the symptoms of a Baker’s cyst — such as swelling, warmth, and redness — may resemble the symptoms of RA.

Many myRAteam members have described what Baker’s cysts feel like. One member shared how their Baker’s cysts were “hurting really bad all day and hard as a rock and very big.”

Another wrote that theirs are “very painful and put added pressure on the joints,” while a third said that their cyst interferes with their sleep: “It’s so painful at night. It keeps me up.”

Some members find that the pain from Baker’s cysts comes and goes, while others experience no pain at all. “After the initial pain for a day, it’s like it’s gone … I had to walk with a cane, but now, it’s no problem,” wrote a myRAteam member. “I’m keeping my legs up in a recliner and icing now and then.”

Yet another member shared that their cyst “has never seemed to give me any trouble.”

What Are Potential Complications of Baker’s Cysts?

On rare occasions, Baker’s cysts may cause complications. These cysts may grow in size, causing or worsening skin discoloration and swelling. In some cases, a Baker’s cyst may rupture (burst) and leak synovial fluid into the calf area. This can cause redness, warmth, and pain or the sensation that water is running down your calf. Symptoms of a ruptured Baker’s cyst may resemble those of deep vein thrombosis (a blood clot in a vein in the leg).

One myRAteam member described their experience with a ruptured Baker’s cyst: “Mine burst, and that was the beginning of the two-year flare I’ve been experiencing. … The pain can be unbearable! Please be careful, as I didn’t realize the severity of it for us that have RA. I just kept pushing through and ended up with surgery.”

A ruptured Baker’s cyst can lead to other potential complications, including:

• Trapped tibial nerve — This complication occurs when the tibial nerve behind the leg becomes trapped under pressure, causing calf pain and numbness in the back of the leg.
• Popliteal artery blockage — A blockage of the artery deep in the back of the knee can cause pain and decreased blood flow to the leg.
• Compartment syndrome — This syndrome causes severe pain alongside problems moving the toes or feet. Compartment syndrome is a medical emergency that requires immediate surgery to prevent muscle damage.

How Are Baker’s Cysts Diagnosed?

If your rheumatologist suspects you have a Baker’s cyst, they will likely start by asking about your symptoms and performing a physical examination, closely examining your knee for signs of inflammation and swelling. Although common in people with RA, Baker’s cysts may elude clinical detection. For this reason, ultrasound imaging is often used to diagnose them. These scans produce highly detailed images of the area and can be used to rule out other causes of swelling, such as a tumor or blood clot. Your doctor may also recommend an X-ray or an MRI scan, if additional imaging would be helpful for the diagnosis or treatment.

How Are Baker’s Cysts Treated?

In some cases, Baker’s cysts disappear on their own without treatment. You also likely won’t require treatment if a Baker’s cyst isn’t causing symptoms. If a Baker’s cyst becomes large and painful, your doctor may recommend the following treatments.

Treatment for Rheumatoid Arthritis

Treating a Baker’s cyst often involves treating your underlying condition — in this case, rheumatoid arthritis. There are several types of treatments for RA, including oral medications, injections, surgery, and lifestyle changes like diet and exercise. You and your rheumatologist can work together to find the right treatments for you.

Steroid Injections

Corticosteroid medications or a cortisone shot may be injected directly into the knee joint to reduce inflammation and help relieve pain. They also can be injected directly into the cyst. Steroid injections may not prevent the cyst from returning, so you may require additional treatment in the future.

Fluid Drainage

Your doctor may determine that the best option for treating your Baker’s cyst is to use a needle to drain the buildup of fluid from the space behind the knee joint. After drainage, the joint may be injected with steroids.

Many myRAteam members have undergone needle aspiration to treat their Baker’s cysts. “I opted to have it drained,” one member shared. “I’ve had it done twice in the last two years. It has helped tremendously for me.”

Another member described the relief that came from this procedure after experiencing considerable knee pain and pressure from their cyst. “When they drain it, some of that pressure is released, and it feels so much better. They numb it, so you don’t really feel it,” they wrote.

Physical Therapy

Your doctor may recommend seeing a physical therapist to help improve your symptoms. These professionals can guide you through gentle exercises to strengthen and improve range of motion in muscles around the knee joint. A physical therapist may also recommend supportive aids like compression wraps.

Surgery

Most people with Baker’s cysts don’t require surgery. Surgical procedures are usually reserved for cysts that are severe and have not responded to other treatments. As one myRAteam member whose cyst had ruptured shared, “I ended up getting a synovectomy (removing the synovial membrane) in order to stop the fluid.”

Cysts can also come back after surgery.

How Can You Manage Baker’s Cysts at Home?

Your doctor may recommend taking several steps to manage an RA-related Baker’s cyst.

Use Pain Relievers

Over-the-counter pain relievers can help reduce pain and swelling caused by Baker’s cysts. These medications include naproxen and acetaminophen as well as nonsteroidal anti-inflammatory drugs (or NSAIDs) such as ibuprofen or aspirin. Talk to your doctor before taking these medications to determine the right dosage and frequency for managing your symptoms.

Try Rest, Ice, Compression, Elevation (RICE)

Your doctor may recommend following the RICE protocol: rest, ice, compression, and elevation. Give your joint plenty of time to rest, and elevate (prop up) your leg when possible, especially at night. Placing an ice pack or bag of frozen peas wrapped in a dishcloth on the affected area for 10 to 20 minutes can help reduce swelling. Compression bandages, wraps, sleeves, and braces can also help support the knee joint.

One member shared their tips: “Ice helps. Put ice up on a pillow at nighttime. Lay flat on your back.”

Take It Easy

Reducing your physical activity can help lessen strain and irritation in the knee joint. Your doctor or a physical therapist can advise you on the right amount of exercise and activity to minimize pain and swelling.

Join the Conversation

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What treatments have been most or least effective for a Baker’s cyst with RA? Let others know in the comments below.