Sgt. Jorge De Leon wears a $70,000 titanium and carbon-fiber prosthetic right leg with a microprocessor that measures his footfall 50 times a second, enabling him to walk slowly or quickly, climb stairs and otherwise get on with life as normally as possible.

Servo-motors that open and close hydraulic valves — increasing or decreasing the swinging motion of his leg in place of a knee — are powered by a small lithium-ion battery he has to charge every two days.

"I drive my car with this leg, I ride my bicycle, I ride a motorcycle, I do marathons, I cut the grass — I do everything and I don't have to worry about it," said the 32-year-old Schofield Barracks soldier from Bayamon, Puerto Rico.

De Leon's leg was severed when two land mines exploded beneath his Humvee in Afghanistan on May 12, 2004.

"But the benefits are getting better than they used to be, and with the technology going this way, it's going to be better in the future," he said.

Since 2003, war amputees have been outfitted with microprocessor-controlled prosthetic legs as part of a host of advances in artificial limb technology. In doing so, the military has strived to make life beyond the war zone as comfortable as possible.

De Leon is among about 15 people in Hawai'i — car accident victims included — who have microprocessor-enabled limbs, said Kai Newton, a certified prosthetist/orthotist who works with De Leon.

By comparison, Schofield soldier Spc. Brandon Wooldridge, 24, whose calf was shredded by gunfire or a rocket-propelled grenade in Iraq, wears a prosthesis below the knee and retains his knee's natural function.

Said Newton: "I get calls on it (microprocessor technology) more regularly from doctors and individuals, and it is getting to be more the accepted thing."

In the meantime, the Pentagon is outfitting a growing number of bionic men and women.

MORE TROOPS SURVIVING

William Winkenwerder Jr., the Pentagon's assistant secretary for health affairs, told a Congressional panel that while service members are surviving injuries in record numbers — in part because of improved body armor — the U.S. government has to step up treatment and care for severely injured troops.

"Assistive technology" centers for amputees are offered at Walter Reed Army Medical Center in Washington, D.C., and Brooke Army Medical Center in Texas. The Brooke amputee care center opened in January with the goal of returning patients to their "highest possible level of activity."

Walter Reed, the U.S. military's first amputee care center, has cared for more than 280 troops who were wounded in Iraq or Afghanistan, Winkenwerder said.

De Leon, who has been in the Army almost five years, lost his leg on his second deployment to Afghanistan, as he drove back to base in Ghazni. Two mines stacked together blew up the front of the Humvee.

He was pulled out of the wrecked vehicle by fellow soldiers with the 2nd Battalion, 5th Infantry. His right leg stayed inside.

"All I was thinking about was my wife and kids," said the father of three. "I asked about my gunner, if he was OK, and about the other guys inside."

De Leon spent six months at Walter Reed.

"I was lucky. My family was with me — my wife, my kids, my mom. Everybody flew in from Puerto Rico to spend time with me, so I wasn't depressed," he said. "I watched a lot of guys getting really depressed at Walter Reed, but I had my family with me, and I said: 'I can't stop now. God gave me a second chance to live. I'm not going to waste it being depressed.' "

He has three artificial legs: the C-Leg (the "C" stands for computer), a running leg and a swimming leg. Neither the running leg nor the swimming leg has microprocessors, but both are in the $15,000 to $20,000 range.

De Leon sometimes makes weekly visits to see Newton, who is with Advanced Prosthetics & Orthotics of the Pacific, a provider through Tricare, De Leon's military insurance.

Some visits are needed to replace the carbon fiber sockets into which the remainder of his leg fits. One secures by suction and another is held by mechanical means.

"It's not painful, but it's uncomfortable," De Leon said. "At the beginning, the leg sweats until you get used to it."

The C-Leg has settings for walking and biking, and ranges within each. To switch between the two, De Leon extends his leg behind him and bounces on his toe three times. The knee beeps and vibrates, signaling the setting change.

The C-Leg mechanics do not propel his leg but, rather, create the right amount of resistance for forward momentum.

Last week, Newton had De Leon's leg hooked up to a laptop, from which he made adjustments.

Bluetooth wireless technology lets him fine-tune from a distance of 300 feet, so Newton could accompany De Leon to a track and tweak settings from the stands.

"It's far and away the largest leap, the largest advance in prosthetic knee technology in probably close to 30, 40 years," said Newton, the only person in Hawai'i certified to work with the prosthetic. The C-Leg was introduced in the United States in 1999.

PROSTHETIC 'SO NORMAL'

Forty years ago, the "technology was so basic," Newton said. Leg sockets were made out of wood, offering the equivalent of a door hinge at the knee.

With the C-Leg, data is taken 50 times a second by sensors monitoring the gait, and algorithms based on thousands of gait patterns anticipate what's coming next and react accordingly.

For biking, De Leon's leg loosens the bending resistance. It knows when to lock when he's going up or down stairs. The leg locks straight if the battery isn't recharged. That prevents it from buckling and the 6-foot-1, 240-pound De Leon from crashing.

He's used to the leg, and so is his family. His 4-year-old son, for example, will bring his dad's leg to him.

"The kids are pretty cool with it," De Leon said. "To them, it's so normal, because they don't know any differently."

He can even joke about it.

Taking off his white leather basketball hightop and propping his rubbery, beige artificial foot on a nearby chair, De Leon points out his name on the sole.

"You know 'Toy Story'?" De Leon asks, referring to the popular computer-animated movie. "The toys have 'Andy.' I have my name" written on the foot.

Despite his command of the prosthetic gear, De Leon is not sure where it will take him in the future.

He wants to stay in the Army, maybe become an MP or join Criminal Investigative operations because he was a police officer in Puerto Rico. De Leon said he cannot remain in the infantry, because he lost his leg above the knee.

Army officials told him he'll receive 60 percent of his pay if he goes on disability, but the amount could be negotiable.

"I'm thinking about it. There are some rumors that if I stay in, they'll find me fit for duty and I'll lose (any chance for) disability," he said.

"I think I did what I had to do for my country. Now, my family's going to be first, and if I have to get out, I will get out."

Reach William Cole at wcole@honoluluadvertiser.com.