In the history of war, the more proficient combatants have become at fighting, the better medicine has become at healing.
During World War II, battlefield doctors devised better techniques to repair delicate blood vessels, essentially rewriting the textbooks on vascular surgery. The Vietnam War sparked swift helicopter evacuation of the wounded that was soon copied by urban medical centers throughout the United States.
For the wars in Iraq and Afghanistan, the medical legacy will probably belong to the amputee. The rate of amputation injuries among U.S. troops in these conflicts is almost twice as high as in any previous American military conflict, because of insurgents' predominant use of explosives. Some troops who would have died in past wars are being saved by body armor, which doesn't protect arms and legs.
Government agencies, private companies and independent researchers are creating more high-tech prosthetic limbs in response. In doing so, they're pushing the boundaries of what researchers and doctors once thought possible.
"Never has there been a time, in my experience, where the amputee has been offered so much to overcome the obstacles of having to adjust to their new body," said Robert S. Gailey Jr., assistant professor of physical therapy at the University of Miami and a longtime prosthetics researcher. "These young men and women will never understand what those who lost a limb 25 years ago had to go through."
Unlike the dead-weighted and immutable arms, feet and knees offered to veterans of the Vietnam War, the best prosthetic knees currently available rely on artificial intelligence to anticipate the user's movements. One knee, expected to become available in a few months, will even mimic lost muscle activity by powering ankle and leg amputees up stairs, or up from a sitting position.
But that's just the beginning. Advances in robotics, electronics and tissue engineering ultimately could create ways to lengthen damaged limbs, grow new cartilage, skin and bone, and permanently affix a prosthesis to the body. Some researchers are even designing a so-called biohybrid limb -- a prosthesis that can be controlled by the user's thoughts.
The biohybrid limb is designed to reduce the amount of effort needed to move the limb and thus limit falls, increase feelings of security and improve self-image. The user of such a leg could spring from the sofa to catch a baby who is about to tumble from a highchair.
In short, researchers predict, it would be as good as a natural human limb
"A decade or two ago we imagined a neural interface, but it was science fiction," said Hugh Herr, a researcher at the Massachusetts Institute of Technology who lost his feet at age 17 to frostbite during mountain climbing. "But now these things are pretty close to being realized in the laboratory."
The advancements resulting from the latest American wars are defined largely by the fact that battle injuries have changed -- as have the soldiers.
Only 10% of the U.S. casualties in Iraq have been deaths, compared with 30% in World War II and 24% in Vietnam, according to a 2004 study in the New England Journal of Medicine.
But 6% of the wounded have required amputations, compared with 3% in past wars, according to a U.S. Senate report. As of last March, the most recent data available, 428 amputations were reported from U.S. troops in Iraq.
Meanwhile, the current generation of GI amputees is the most athletic of any American war, doctors say, with high expectations for their recovery. Some are remaining as active-duty troops, and at least one foot amputee has returned to action in Iraq.
"They want prosthetics that return them to high levels of function," said Robert Ruff, a neurologist and acting director of rehabilitation research for the Department of Veterans Affairs. "The soldiers are in excellent cardiovascular shape, so they place more demand on the prostheses."
And for troops to recover, physically and psychologically, from amputations, they need hope and the best that technology has to offer.
Chang Wong, 23, of Alhambra was a high school wrestler who prided himself on his fitness, before he lost both legs just below the knees while serving in Iraq. Now he's using his former image of himself to boost his recovery, recently learning to run on his prostheses.
On a day in late December he sat on the curb of the track inside a health club in Rosemead and popped on his running feet: high-tech titanium and carbon fiber appendages that looked a little like curved skis with thick rubber soles of running shoes glued to the bottoms. He stood up with a bounce -- the prosthetic running feet provide so much flexibility that Wong springs slightly when he walks. He headed down the track and out of sight, steady and quick as the next guy.
He's come a long way. Last May, the tank in which Wong was riding struck an improvised explosive device buried in a dirt road outside Baghdad. Wong, in the gunner's seat on the floor, bore the brunt of the explosion.