Fact
Adults grew a new bone in the last century
The fabella, behind the knee, is three times more common than it was in 1918.
The fabella is a small sesamoid bone in a tendon behind the knee. A review of over 21,000 knees found its prevalence rose from about 11 per cent in 1918 to roughly 39 per cent by 2018. The leading explanation is better nutrition producing longer, heavier bodies and greater tension on the tendon.