Article by the Drummond Team
This tiny bone (the name actually means “little bean” – and is a sesamoid bone from the Latin meaning Sesame seed) sits in the tendon behind the knee, and has been linked to arthritis. It used to be rare in humans, but recent research from the Imperial College London has discovered its becoming increasingly more common.
Researchers believe its come-back might be because we are eating better foods, and have higher nutrition standards. However, its purpose is still not 100% certain – it may be similar to other sesamoid bones – to help reduce the friction within tendons – or it may serve no purpose at all!
Between 1918 and 2018, its presence grew by more than 3 times – from 11% of the world’s population to 39%! And strangely enough, people who suffer with osteoarthritis are 2 times as likely to have a fabella bone than those without the condition (but doctors and scientists are uncertain if it causes osteoarthritis, or what its relevance is)
In some primates, the fabella acted as a “knee-cap”, but as apes and humans evolved, it began to disappear. Sadly, it now just causes problems for humans. The mystery is, why is it making such a strong come back?? One theory is that as our nutritional standards improve, this means humans are taller and heavier in weight, placing more pressure on the legs and knee bones. As sesamoid bones act like “pulleys” and offer a smooth surface for the tendons to slide across, they adapt to the movements and weight put on them. We’re sure that in time, its purpose will be revealed!
(Note: the study was funded by the National institute for Health Research)