Majetich’s feeling that a “phantom” hand is real is the result of a groundbreaking type of arm amputation performed in the summer of 2020 at Walter Reed National Military Medical Center in Bethesda, Md. First developed for patients requiring leg amputations, the experimental procedure recreates the connections between muscles that are lost in standard amputation surgery. Majetich was the first person to undergo the procedure on an arm.

The surgeons and engineers who pioneered the technique designed it to restore what’s known as proprioception. That’s the brain’s ability to sense where our limbs are in space and how fast and forcefully they’re moving. It doesn’t work when muscles are no longer paired up as they normally are, with one contracting and the other stretching.

The idea behind the new procedure is to help patients’ brains superimpose a phantom limb over a prosthetic one — and allow them to perceive the prosthetic as their own arm or leg. “The relevance of that is we believe it gives people a fuller sense of restoration of their body,” said Matthew Carty, the plastic surgeon who examined Majetich that afternoon last May.