Steroid Injection for a Baker’s Cyst

A Baker’s cyst, also known as a popliteal cyst, is a fluid-filled swelling located behind the knee. This is due to excess fluid in the knee joint due to an injury or underlying condition.

Causes

A Baker’s cyst typically develops as a result of a previous knee injury or underlying issue within the knee joint, such as:

• Osteoarthritis
• Meniscus tear / ACL tear
• Rheumatoid arthritis / Gout

These conditions lead to excess synovial fluid in the joint, which collects at the back of the knee.

Symptoms of a Baker’s Cyst

Symptoms of a Baker’s cyst may include:

• Pain in the back of the knee and calf
• Swelling at the back of the knee
• Limited range of motion when bending the knee
• Stiffness or feeling of fullness in the knee when moving the knee

In some cases, there may be no pain or other symptoms aside from the swelling behind the knee.

Baker’s cysts can occasionally rupture, causing fluid to leak into the calf. This may result in sharp pain in the knee or calf, along with swelling and redness in the calf.

Anatomy

The knee joint is a hinge joint that is made up of the femur (thigh bone) and the tibia (shin bone). There is a membrane surrounding the knee joint, which produces synovial fluid to lubricate the joint.

Behind the knee is a diamond-shaped space called the popliteal fossa. If there is excess synovial fluid due to an injury or condition, it then collects in this space behind the knee.

How to diagnose

A diagnosis can be made through taking a thorough medical history, physical examination and imaging. The physiotherapist will ask about any pain, swelling, stiffness, injuries or any underlying conditions. They will then assess the knee physically, performing a series of tests. An ultrasound scan may be performed to confirm the presence of fluid and identify if there is a Baker’s cyst.

Treatment

Majority of Baker’s cysts will resolve by themselves, however if symptoms do not improve, the Baker’s cyst can be drained. The procedure involves inserting a fine needle into the Baker’s cyst under ultrasound guidance to ensure precision. The fluid is drawn out, which immediately relieves pressure and improves mobility. For further information on aspiration, please click here

A steroid injection may also be administered after an aspiration to reduce inflammation and help reduce risk of the Baker’s cyst reoccurring. 

Physiotherapy
Strengthening the muscles around your knee can help stabilise and protect the joint. As most conditions causing a Baker’s cyst are related to either joint deterioration or “wear and tear” issues, it is important to include this as part of your management as well. 

Baker’s Cyst Steroid Injection therapy

If symptoms do not improve with conservative treatment like Physiotherapy or if the pain is affecting your ability to squat, perform daily activities or play sport then an aspiration may be beneficial for you.

An aspiration is a quick procedure that can be done in clinic under ultrasound guidance and may provide you with relief so that you can return to doing activities again with less restriction. 

If we do aspirate the Baker’s cyst, we may offer a small dose of steroid (a strong anti-inflammatory drug) to be administered into the knee joint at the same time. Ultrasound guided steroid injections can be very effective for reducing knee joint pain and inflammation. 

Other Knee Conditions:

• Patellofemoral Pain Syndrome
• Knee Arthritis
• Iliotibial Band Friction Syndrome