What is a Baker’s cyst?

A Baker’s cyst involves a swelling behind the knee.  The swelling is caused by a collection of excess synovial fluid (lubricating fluid) within the bursa between the calf muscle and the knee joint.

Baker’s cysts are also called popliteal cysts.

Who gets it?

Baker’s cyst most commonly occurs in boys aged between 4 and 8 years of age.

What are the sign and symptoms of a Baker’s cyst?

A bakers’ cyst may present as a painless lump behind the knee.  It is most obvious when a child is standing with their knee straight. It usually affects just one leg.

Symptoms associated with a baker’s cyst vary. Some children experiencing no discomfort at all. Others report a feeling of tightness or pressure at the back of the knee joint when the knee is straight and some children experience aching at the back of the knee after strenuous exercise.

It is common for the size of the cyst to vary throughout the day.

What is the natural history of a Baker’s cyst?

The natural history of a Baker’s cyst in children is that the cyst will disappear spontaneously without the need for treatment.  It is common for the cyst to get bigger before it finally resolves and the time that it takes to resolve is highly variable.

There are no long-term problems to the knee or the child from a Baker’s cyst.

What is the treatment for a Baker’s Cyst?

Treatment of a Baker’s cyst in children is usually not required.

What tests are used to diagnose a Baker’s cyst?

A Baker’s cyst is diagnosed using a clinical examination. Shining a light through the cyst can determine if the lump is fluid filled. Therefore, an Ultrasound or CT scan is not usually required to diagnose a Baker’s cyst.