About 65,000 amputations are performed in the US each year.
They happen because of diseases or trauma.
Losing a leg can be especially hard, because it can force some to give up their independence.
Scott Tjaden competed in two Paralympics.
He is also an avid hunter and loves a good game of catch.
He lost his leg to bone cancer when he was nine, but it has not held him back.
This computerized leg has a microprocessor that calculates every move Scott makes 50 times a second. “It's sensing the demand that is being placed on the knee and making adjustments for that demand,” says Dr. Kenton Kauffman of the Mayo Clinic.
A computer chip sits inside the knee and controls how much the hydraulic valves open.
Scott can adjust the resistance of the valves with his wireless remote, changing his pace from fast to slow.
The leg costs about $50,000.00 dollars and is not always covered by insurance.
The computerized leg is only for patients with above the knee amputations.