Fabella

Written by Dr Sheila Strover on March 14, 2025

A fabella is a little bone which sometimes forms at the back of the knee, within the tendon of the gastrocnemius muscle, like a tiny kneecap at the back of the knee.

The arrow shows the fabella.

The fabella is a normal anatomical variant

The fabella is a normal variant in 10-20% of people. The little bone is often wrongly diagnosed by the inexperienced doctor as a 'loose body' or even a 'foreign body' inside the knee. However, in rare cases the fabella causes posterolateral knee pain and surgeons may choose to excise it.

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What is fabella pain syndrome?

In fabella pain syndrome the patient complains of posterolateral knee pain which is worse when the leg is fully extended.

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