For decades, a soldier's lost limb meant a life confined to a wheelchair or crutches, and at the very least a discharge from active service. But an increasing number of injuries in the Iraq and Afghanistan wars, while horrific, have led by necessity to advancements in prosthetics technology. In fact, some amputee service members have been able to remain on active duty, thanks to the experience earned by their doctors.

According to the Army, at least 167 soldiers who have had a major limb amputation (complete loss of an arm, leg, hand, or foot) have remained on active duty since the start of the Afghanistan and Iraq wars, with some returning to battle. Many others have returned overseas to work in support roles behind the lines.

"When we have someone we know wants to return, their rehab is geared that way," says John Fergason, chief of prosthetics at the Army Center for the Intrepid at Fort Sam in Houston, Texas.

Kevin Carroll, vice president of Prosthetics at Hanger, a company that makes artificial limbs, says prosthetics have become more comfortable to wear and closer in range of motion to natural limbs.

"Unfortunately, when you have war, you have casualties, but with that comes innovation," he says. Artificial joints are getting better at approximating the knee, elbow, wrist, and ankle, and microprocessors embedded in prostheses are able to pick up and adjust for impacts from walking, running, jumping, and climbing.

"The person doesn't have to worry about the prosthetic device, they're worrying about the task in front of them," Carroll says. "If they want to go back to be with their troops, that's an option for many soldiers these days."

Fergason and his colleague, Ryan Blanck, say that each branch of the military has its own guidelines for allowing an amputated soldier to return to work, depending on his or her task. In many cases, it takes at least a year for a soldier to return to duty. The requirements for a fighter pilot, for instance, will be different than those for an infantryman or a behind-the-scenes supplies manager.

"It's the soldier's decision in the end," Blanck says. "Each case is unique to each person in some ways, just as each injury is unique—there's some fluidity behind it all."

But Fergason says that the soldiers who are going back into battle are able to perform just as well, if not better, than some of their fellow soldiers.

"If an individual is going back to full battle status, they need to perform at the same physical level as their colleagues," he says. "If they don't feel they can do exactly what they were doing before the injury, they can reclassify into a different position."

And for all the advances in technology, both Fergason and Blanck say it's the soldier's drive, not their prostheses, that allows them to return to work. In fact, many of the soldiers they work with use high-tech, battery-powered prostheses when they're behind the scenes, but in battle, they might want something more low-tech. The worst thing, Blanck says, would be for a soldier to be stranded in Kabul with a prosthetic leg that's run out of batteries.

"They have the opportunity to utilize technology that is very advanced, but when it comes down to it, they're most likely using something that's not subject to failure, something that's durable and reliable," he says. "They're using something a little more simplistic so they can strap and go. They don't want to have to worry about failure issues because of an electronic malfunction."

Those drawbacks, and the fact that prosthetics still have a ways to go before they're superior to natural limbs, means America—or its enemies—won't be training an army of bionic super soldiers anytime soon.

Jonathan Moreno, a bioethicist at the University of Pennsylvania, talks about a future where prosthetics are "enhancers" that allow soldiers to be stronger, faster, and more durable than their peers. Carroll says there's a "very bright future" for powered prosthetics that allow soldiers to lift extremely heavy objects with little effort. He points to Oscar Pistorius, the South African, double-amputee sprinter who will likely participate at the Olympics this summer.

"There's a lot of controversy that his prosthetics might be so advanced that he has an advantage over a person's natural limbs," he says. But in a battlefield setting, there's still a long way to go, Fergason and Blanck say.

"I know the question is often, 'How close are we to true bionic or having artificial limbs that are more versatile than natural ones?'" Fergason says. "Frankly, we're not that close. You're not going to see anyone decide, 'Boy, I think I'd like to get a bionic leg because they're so fantastic.'

"We love to read about the super soldier, but that's not the case right now. Amputation is so complex in what it does to your body that it's a very long recovery," he adds. "I think the aspect of a super soldier is a long way off."

So for now, soldiers have to get by with existing prosthetics and try to perform as well as they did before the injury—which raises the question of whether it is fair to ask someone who has already given an arm or a leg for his or her country to keep fighting. Col. GI Wilson, a Marine Corps Iraq veteran, says that not only is it fair, it'd be unconscionable to keep these soldiers out of duty.

"Letting an amputee who can perform to standard serve makes more sense than asking them to be a victim and sent home," he says. "The amputees who want to serve want a paycheck, not a government disability check."