FRIDAY, March 19 (HealthDayNews) -- The warfare in Iraq, a year old Friday, has left hundreds of American soldiers dead and thousands injured, many without arms or legs.

High-tech prosthetic devices are offering hope to many of the most badly injured, although doctors acknowledge that artificial limb technology still has plenty of room for improvement.

Soldiers, for example, can be given a prosthetic leg, "which is much more efficient than hopping around on one foot with crutches," says Dr. Edwin Richter, associate clinical director at the Rusk Institute of Rehabilitation Medicine in New York City. But, he adds, even a prosthesis with a microprocessor built in "is not a good substitute for a normal healthy knee."

Amputation has long been a grim occupational hazard for soldiers.

"A lot more limbs are saved than there used to be, but there are times when there isn't enough skin or nerve supply or the architecture of the bones is smashed too badly," Richter says. "There's no way for surgeons to save the limb, and they have to prioritize and save the person."

Replacing the leg is far from a simple chore. Legs are complicated machines, full of muscles and bones finely calibrated to work together. A stiff artificial leg, like a wooden peg, lacks flexibility of movement. But a fake leg with a flexible knee joint isn't necessarily a great improvement, says Dr. Albert Esquenazi, chairman of the department of physical medicine and rehabilitation at Albert Einstein Medical Center in Philadelphia.

Why? Because if someone moves too quickly, the lower leg could whip back and slap him or her in the buttocks, says Esquenazi, who is himself an amputee who lost part of his right arm in a chemical accident. "That's a major problem for individuals who want to be able to return to high levels of activity or walk at different speeds."

Enter the microprocessor. New prosthetic knees come with computers that sense movement in the leg and detect whether it is standing or off the ground and moving forward. "The microprocessor can detect which one of the two you are doing," Esquenazi says, and adjust the artificial knee joint accordingly.

In another advance, electronics in artificial legs and hands improve the ability of amputees to control the limbs.

But computers aren't cure-alls. While they can help amputees avoid stumbles and falls, they still don't allow them to walk up stairs normally. Amputees typically must lift their artificial legs from step to step.

And the simple act of walking from place to place can be exhausting for an amputee. "People are adaptable, and some learn to walk quite well and have good enough balance that they don't need a cane or a walker," Richter says. "But they're still working harder than they would have if they had two healthy legs of their own."

What's next? When they dream of better technology for amputees, doctors think about artificial limbs that are easier to manipulate. Technology provides "a little bit of control, but nothing like what the human body is used to," Richter says.

In other words, artificial is still far from natural.

More information

Check the Amputee Coalition of America to get answers to FAQs. You can also try the Alliance for Technology Access.