Baker's Cyst


The Baker’s cyst is a swelling at the back of the knee and is often known as a popliteal cyst. Baker’s cysts are fairly common and are associated with joint swelling in the knee. This swelling is almost always caused from damage to the joint itself such as torn cartilage or arthritis. Occasionally it becomes enlarged for other reasons such as after knee surgery. These conditions all cause the knee to produce too much fluid which results in a Baker’s cyst.

The size of the cyst can vary a lot depending on the amount of fluid in it, there is a valve that regulates the flow of fluid from the joint capsule into the cyst. If the valve only allowing fluid to flow into the cyst as in the case in knee pathology the cyst increases in size and can become very noticeable and painful. Baker’s cysts can enlarge and shrink and on rare occasions they can actually burst. The fluid from the bursa is normally absorbed by the body but the bursa will normally reappear over time.



Signs and symptoms of a Baker’s cyst:

  • The main sign is swelling behind the knee.
  • This swelling may be soft to touch and slightly tender.
  • As the knee moves into extension it can become tighter and more painful.


Treatment involves treating the cause of the swelling ie the menical tear or arthritis. Once the cause has been treated the swelling generally dies down. Sometimes the bursa may be drained or removed surgically. But if the underlying cause of the bursa isn’t corrected the bursa will just return.

Physiotherapy techniques include:

  • Treatment to reduce the swelling.
  • Massage.
  • Stretches to help restore flexibility of the surrounding muscles.
  • Strengthening of spupporting muscles.
  • Improving the biomechanics of the knee so that aggravation doesn’t reoccur.
  • Improving the dysfunction in the knee whether it is arthritis or a meniscal tear.