Victhom...(VHB) Next Leg UP....A leg up
By Jon Rutter, Staff Writer
Sunday News
Published: Jul 01, 2006 11:56 PM EST
LANCASTER COUNTY, PA - Power Knee, a prosthesis that works with good leg, allows amputees to take steps without limp. It gives this wounded Ranger a leg up.
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On its second pass the gunship started shooting too early.
A couple of rounds struck Bill Dunham in the back. Three more tore into his right leg.
Two other paratroopers in Dunham’s five-member U.S. Army Rangers team were killed by the friendly fire.
That was in 1990, during Operation Just Cause to apprehend Panamanian dictator Manuel Noriega. Dunham was shot trying to secure Rio Hato airfield.
It took 12 hours to evacuate him to San Antonio, Texas, and 13 surgeries to try to save his leg.
It would be 16 years before he got the Power Knee, a new prosthesis that for the first time allows amputees to walk up stairs with a natural gait.
Dunham described navigating 75 stadium steps at a recent Minnesota Twins game.
“I didn’t stop,” he marveled. “I didn’t pause. I just kept on moving.”
The 37-year-old former military man from Rogers, Ark., said he was the first amputee to buy a Power Knee production model, in January.
He was in Lancaster County two weeks ago to demonstrate the high-tech device, which is marketed by Hanger Prosthetics and Orthotics in the United States and manufactured by Ossur Bionic Technology of Iceland.
Gary Reinhold, a certified prosthetist with Hanger in Elizabethtown, said artificial intelligence allows the prosthetic to work in conjunction with the healthy limb.
Unlike previous-generation prosthetics, Reinhold said, Power Knee gears and electric motors actually help propel the user, as would muscles.
“It is far beyond what anybody could ever have imagined.”
The next step
Certainly, Dunham could not have seen a Power Knee in his future.
Eight days after he was wounded, his prognosis was grim. He’d barely survived and he’d lost a lot of blood. “My big toe ... looked kind of like an avocado in color and size,” he recalled.
Even if his leg could be saved, the knee and ankle joints would be forever fused. He talked with his doctors for about half an hour before telling them to take off the limb above the knee.
His first artificial leg was wooden.
Then came a hydraulic knee, which tended to collapse under his full weight.
The C-Leg, also a computerized prosthesis, was a huge improvement that Dunhill still uses.
But he says the Power Knee has taken him to the next plane of mobility.
“This was the first time I’ve been able to walk step over step up stairs.”
Not long ago, he added, he and his wife went to the beach in South Carolina. He strolled through the sand — harder to do with a conventional prosthesis — and then removed his leg and went into the water.
“I think it’s pretty cool,” said Dunhill, a husky man with a pleasant Southern drawl. “They’re really pushing the envelope.”
Invented and designed by Victhom Human Bionics in Canada, the high-impact plastic Power Knee won a Popular Science Best of What’s New Award in 2005.
A rechargeable battery powers it. Componentry manufactured by Ossur in Reykjavik, Iceland, drives the concept, Reinhold explained.
Patients wear a shoe with a computerized insole on their existing foot. Sensors in the insole read the movement and location of the healthy limb. A small transmitter strapped to the ankle relays the information to a microprocessor in the Power Knee, which is attached to a socket on the patient’s leg.
The prosthesis then positions itself automatically so that the wearer does not have to think about each step.
The leg is so powerful that it can literally lift someone out of a chair, Reinhold said. “The knee knows what to do. The knee walks the patient ... it duplicates human locomotion.”
Reinhold, one of a handful of practitioners qualified to fit the Power Knee, helped with pilot testing last summer.
Designed for people who have lost one leg above the knee, the Power Knee can be programmed to accommodate a wide range of individual gaits and sizes, from 135 to 220 pounds.
The downside is that it’s expensive — $120,000, according to Reinhold, compared to $40,000 or $50,000 for a more conventional prosthesis.
Reinhold said Hanger is working to obtain Medicare funding for Power Knee patients.
The company is also upgrading the device to dampen its whirring sound, according to Dunhill.
He said he has helped publicize the Power Knee in Pennsylvania, New York, Louisiana, Texas, Oklahoma and Florida.
While the majority of Reinhold’s patients suffer from diabetes complications or vascular disease, battle-related amputations comprise a rapidly growing segment.
Dunhill said better trauma care and body armor have allowed many grievously wounded soldiers from Afghanistan and Iraq to survive wounds that would have killed them in previous wars.
Some are triple, or even quadruple, amputees.
Dunhill, a defense-issues expert who is pursuing a teaching post, said he visits wounded veterans to try to inspire — and to be inspired.
While no machine can ever replace a real limb, he said, new technology can help give some people hope.
A bionic ankle is already in the works, according to Reinhold, and science might one day be able to graft a prosthesis directly to a femur bone.
Meanwhile, Reinhold and Dunhill agree, the Power Knee is a real breakthrough for single-leg amputees.
Dunhill said the new device weighs about 7 pounds more than his other prosthesis but offsets that with its ease of use.
He chooses the Power Knee when he wants to cover a lot of ground, such as on shopping trips to the mall.
Though it’s hard to quantify, Dunhill said, “The Power Knee seems to be giving me the ability to walk farther ... It tends to feel more natural.”
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Contact Jon Rutter at jrutter@lnpnews.com