Jennifer Mathews: Fifteen years ago Chris Culross met his wife, Andrea, and found a new hobby.

Chris Culross: I was over at her house and her mother pulled some out one day and said, here, have some pancakes and maple syrup that she made, and I thought that was the best idea.

Jennifer Mathews: But tapping trees for syrup took on a new challenge when Chris lost his leg in a car accident. His first prosthetic was not what he expected.

Chris Culross: A wire came up and that's how I had to pull it to bend it.

Jennifer Mathews: Even walking on smooth surfaces required total concentration.

Chris Culross: Even in a building, if there was a little bump on the floor, I'd hit it and tumble.

Jennifer Mathews: Determined to find something better, Chris went to Harvey Sosnoff. He fitted Chris with a new leg called a C-Leg, short for computerized leg.

Harvey Sosnoff: This is a live, animated thing that actually get the senses in real time where his knee is.

Jennifer Mathews: Fifty times a second, a computer chip reads the amount of pressure on his foot and the position of his knee. Real time adjustments inside the knee keep Chris steady on his feet. For Chris, the benefits are more than he could have imagined.

Chris Culross: I've never been able to hold my son and walk. Now, I can.

Jennifer Mathews: This is Jennifer Mathews reporting.