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'Bionic' foot arrives
Computer-aided prosthesis anticipates user's movements
Joel J. Smith / Special to The Detroit News
Joe Foster may not be the $6 million man, but the 42-year-old Northern Michigan resident is one of a handful in the state with a 'bionic' foot, thanks to new technology that is making it easier for some amputees to get around.
No, he can't run 60 miles an hour or leap from a sidewalk to a third-story roof like Lee Majors did in his television series. But for the first time in 16 years as an amputee, Foster can take a pain-free walk up slopes and on long strolls with his wife.
His new foot literally thinks for itself.
Developed by Iceland-based Ossur, the Proprio Foot is billed as the world's first foot prosthesis with artificial intelligence. It has an onboard computer processor that handles 1,000 bits of information per second and uses that data to maneuver the foot more naturally than traditional devices can. A USB port on the ankle part of the device can accept new software downloads.
The $15,000 to $20,000 prosthesis initially was designed by Ossur to handle the influx of military amputations coming out of the Afghanistan and Iraq wars. But the private sector now has seen the huge benefits of the 'bionic' foot and Ossur has set up a network of trained prosthesists to handle fitting the new electronic appendage.
Greg Greenway, prosthesist with Pros-Tech Prosthetics and Orthotics in Troy, is amazed at how well the foot works with amputees.
"From what I've seen so far with the Proprio Foot, the function is superior to anything we've had in the past," Greenway said. "With the Proprio Foot automatically accommodating changes to the terrain, the individual works less and the limbs aren't undergoing excess force inside the sockets."
That translates into less pain from pressure points on the skin and less likelihood of an infection that could cause expensive hospitalization, Greenway said.
Foster got his Proprio Foot in March. Since losing his lower left leg in a 1991 auto accident, he'd lived with constant leg pain from pressure caused by the twisting of standard prosthetics unable to adjust to uneven terrain.
Now he's feeling relief.
"A big difference is my gait," said Foster, who lives in Alanson, near Petoskey. "I used to limp a lot compensating for the pain in the back and leg. But now my walk is smooth. I can wear the foot all day now, where I use to take the other prosthetics off whenever I could."
How it works
The Proprio Foot thinks for itself through the use of artificial intelligence and a computer processor. It's powered by a rechargeable lithium battery that can run continuously for 32 hours. The foot has three sensors, two accelerometers and an angle sensor that allows a high-precision motor to instantly adjust the ankle and foot to uneven terrain and surfaces. Among its abilities:
• The foot senses an incline or decline and adjusts the angle of the foot to handle the slope with minimum effort.
• The Proprio Foot senses when it's in mid-stride and lifts the toe slightly to avoid setting down at a toe-stubbing angle. Scuffing the toe is a leading cause of falls by amputees.
• It even can recognize when a person is walking up or down a staircase and adjust the angle of the foot to place it squarely on the step• Sitting has long been a problem for amputees. With a regular prosthesis, the wearer sits with the leg outstretched and the heel on the ground, causing stress on leg because of the uneven weight. The Proprio Foot senses when an individual is sitting and automatically drops the toe of the foot to make it more comfortable.
Similarly, standing can be problematic for an amputee. Typically, using his arms, the individual has to lift himself up and over his feet before attempting to stand straight up. With the bionic foot, the user simply brings his foot back to the edge of the chair and the foot senses the individual wants to stand up and places the foot flat on the floor. The person simply stands straight up with minimal effort.
• Changing shoes with different size heels is less onerous with the new foot. In less than a minute, the foot can be reprogrammed to adjust to different footwear, from sneakers to a two-inch heel.
Ian Fothergill is in charge of the Ossur Academy, which handles all technical events for the company. He said that traditional prosthetics are set up for level ground. As soon as the ground becomes uneven, he said the foot becomes misaligned and it becomes difficult to walk.
"If we can take that fear of falling away a little bit and give them more confidence in their stride, it will open up many new opportunities for amputees," Fothergill said.
Brian Haehl, 29, of Sterling Heights lost his left leg in a car accident seven years ago. The married father of two toddler boys has had a tough time walking with a traditional prosthetic foot -- especially being on his feet all day as manager of a Radio Shack store. Then last year, Haehl became one of the first in Michigan to receive a Proprio Foot.
"It's made a world of difference to me in my comfort level," he said. "It's amazing what I can do now."
In fact, Haehl feels so confident with his bionic leg he plans to enter two biking events in a national sports competition for amputees.
But the biggest benefit, he said, is being able to play out on the grass with his sons. Recently, he even took his family to the beach to cool off, something he could have never dreamed of in the past, and didn't have any problem negotiating the sand.
Limited availability for foot
Ossur officials are tightlipped about just how many Proprio Foot devices are being used worldwide since its limited launch began about 18 months ago. But they indicated that it's less than 1,000, with perhaps 10 in Michigan. When it comes to double amputees, only "a handful" in the United States and just one in Michigan have the new device.
Right now, Ossur is selling the bionic foot mainly to private-pay customers, the military, those with worker compensation claims and auto accident victims whose medical care is paid by their auto insurance policies.
The vast majority of conventional medical insurance companies and Medicare won't approve payment on a claim for the foot because it's still considered experimental and costs three to four times as much as a standard prosthesis.
"People recognize the benefit of the Proprio Foot," Fothergill said. "Our next obstacle is getting the insurance companies to recognize it, too."