That's no thumb on this man’s hand—it’s his toe! In January 2019, David Lee, a cobbler in England, was trimming the heel of a shoe with a cutting machine that had a very sharp blade. The next thing he knew, his thumb was lying on the floor. Lee was shocked. The accident happened so quickly that it took him a moment to realize the digit had been severed from his right hand.

Lee was afraid he’d never be able to work as a cobbler again. Fortunately, doctors at Royal Derby Hospital were able to replace his missing thumb with one of his big toes. These two body parts share a similar structure and range of motion, says Jill Arrowsmith, one of the surgeons who performed the 10-hour procedure.

A toe transfer is offered only to a patient who has lost a thumb all the way down to the large joint that connects the thumb’s bones to those of the hand. The biggest drawback is that the surgery involves amputating, or cutting off, another body part. Luckily, a foot can function without a big toe—most people who lose one can still walk, run, and jump. A hand without a thumb, though, doesn’t work as well as it usually would.

Thumbs help people to grasp a ball, make a fist, grip a pencil, press the space bar on a keyboard, and give a thumbs-up, among other things. After the operation and months of rehabilitation to regain hand strength and dexterity, Lee was able to do all those things again. Now, thanks to his brand-new “thumb,” he’s back at work at his shop.