WASHINGTON -- Doctors say a revolutionary implant is making a world of difference for children diagnosed with bone tumors.

The implant grows along with the child.

According to doctors, the routine has been that when a child is diagnosed with a tumor in their arm or leg, there is usually a good chance the child would face amputation. But, advances in chemotherapy and bone reconstruction have changed that.

Michael Bean, 13, of Waldorf, Md., had cancer, a bone tumor that was causing him to suffer with leg problems.

Bean had to undergo chemotherapy to shrink the tumor. Then doctors replaced the diseased part of his thighbone and knee joint with the new type of implant that expands.

The implant looks like plastic, but has a metal spring inside.

Doctor Phil Wodajo is an orthopedic oncologist who specializes in bone tumors. Wodajo said that young patients present a special challenge because after replacing a diseased bone with artificial bones and joints, the child's growth would require lots of new surgeries to lengthen the bone implant.

"One problem we had in the past, is that every time you operate on one of these things to lengthen it … you had the chance of causing an infection, doing some nerve damage and it was very painful … and anxiety provoking it would cause more scar tissue," said Wodajo.

Now, the bone implant is lengthened without surgery. Doctors use a special magnetic ring outside the child's body. The ring creates heat that causes the implant to lengthen just a few millimeters.

Doctors said the new implant means that a child may not be able to be as active as they once were, but once the child stops growing, the implant is left in place and is designed to carry them through adulthood.