What is a Baker’s cyst, and how do we treat it?

A Baker’s cyst is a swelling found on the back of the knee joint. It is associated with osteoarthritis, damage to the cartilage or damaged ligaments within the knee.

A Baker’s cyst also referred to as a popliteal cyst, is a fluid-filled swelling that develops at the back of the knee. The cyst which appears as a large lump is benign, and although it can be painful, it is easily treated.

In most cases, Baker’s cysts will heal without treatment and often cause little or no pain. However, if Baker’s cyst itself is painful, it can be drained and then injected with steroids which will help prevent the cyst from growing back.

What is Baker’s cyst pain?

As the swelling forms at the back of the knee, it can cause pressure on the soft tissue structure resulting in pain. It can occur when the knee is either straight or fully bent, causing more stress and tension around the joint.


Symptoms also include –

  • Stiffness
  • pain
  • Reduction of joint movement
  • Pain when extending or flexing the knee
  • Pain on loading activities such as going up and downstairs
  • Joint locking occasionally due to cartilage damage within the knee

Patients often describe a feeling of pressure and pinching pain at the back of the knee. They usually but not always can feel a lump on the back of the knee.

Occasionally a Baker’s cyst will rupture. It can feel like a sudden release of pressure. Often causing a feeling of fluid running down your leg. If this happens swelling and bruising may appear in the calf area of your lower leg.Baker's Cyst - A diagram of a Baker's Cyst

How do you know if you have a Baker’s cyst?

If you experience the symptoms above, you must seek medical guidance from a physiotherapist or a doctor. There are other possible causes of pain and swelling in this area which may require medical attention.

For example, the clinician, when they examine you, will want to rule out possible other diagnoses. These can include deep vein thrombosis or any nerve or blood vessel disorders at the back of the knee.

How long does it take a Baker’s cyst to heal?

Unfortunately, a Baker’s cyst can go on for a very prolonged period, particularly when it is associated with osteoarthritis or ligament damage within the knee. However, occasionally they will rupture after a few weeks. We would advise you to seek treatment if you suffer a new or worsening of chronic knee pain within 4-6 weeks.

How do you treat a Baker’s cyst?

Treatment is not always required. We would only recommend treatment if they are painful or significantly reducing a person’s function.

At Complete Physio, we can perform a full assessment of the knee. It will also include an ultrasound scan. It is significant for the diagnosis and differentiation between a Baker’s Cyst and other possible causes of pain and swelling. Once we have a conclusive diagnosis of a Baker’s cyst, if the cyst itself is painful, this can be aspirated (the fluid drained from the cyst). Then we would inject with a mix of steroid and local anesthetic to settle the area of the cyst and to reduce the pain and inflammation in the knee.

If you would like any further information or would like to book for a review of a possible Baker’s cyst, please contact us on 0207-482-3875 or email to injections@complete-physio.co.uk.