Hand operation.

No I did not stick my hand in a spinning model airplane propeller.
I did, however, require a small procedure done to the ring finger on my left hand correcting what is called "Dupuytren contracture".

Here is an explanation from the internet.

What is a Dupuytren contracture?

Dupuytren contracture is a localized formation of scar tissue beneath the skin of the palm of the hand. The scarring accumulates in a tissue (fascia) that normally covers the tendons that pull the fingers to grip. As Dupuytren contracture progresses, more of the fascia becomes thickened and shortened. Dimpling and puckering of the skin over the area eventually occurs.