A 13 year old girl in Wimbledon England named Kat Reid has become the first person to receive an artificial bone replacement that can be extended in length without surgery as she grows.

In November, orthopaedic surgeons Steve Cannon and Tim Briggs fitted the world's first bionic bone into the thigh of 13-year-old Kat Reid.

The extendable prosthesis, to give it its proper name, is a major breakthrough because it allows Kat's left leg to grow in pace with her right, without her having to undergo further surgery.

Application of an external magnetic field causes the implanted prosthetic part to grow by 1 millimeter at a time.

While the article does not say why Kat Reid needed a prosthetic replacement for her thigh bone many children who must loose a piece of bone as part of a cancer treatment or who were born with a bone defect or who suffered severe damage to a bone in an accident would benefit from an artificial replacement that can be extended without repeated surgeries.