Newsmaker: Prosthetics go high tech

Your legs may not seem all that smart, but they're pretty good at letting you walk without having to think about what you're doing.

That hasn't been the case with artificial limbs, which have long required wearers to put a lot of thought and effort into a simple stride. Now, though, a newer generation of prosthetic devices is making use of chip technology to make walking a more natural act for amputees.

One such device is the C-Leg, from Otto Bock HealthCare, a German company that got its start working with war victims in the first years after World War I. The C-Leg is a decidedly 21st-century device, with a microprocessor in the knee that reads data 50 times a second--from real-time sensor data--to help the wearer negotiate changing terrain. The company also provides upper-body devices such as a new "dynamic arm" that for the first time has power-assist technology in elbow.

Bert Harman, president and CEO of Otto Bock's Americas region, recently spoke with CNET News.com about R&D challenges, getting nerves to talk to prosthetics and the current state of bionics.

Q: How big a business is high-tech prosthetics, and what is Otto Bock's part of that business?
Harman: Well, if you start as high-tech prosthetics, it's relatively small. In fact the whole prosthetics industry is a small industry. In United States alone, there are about 1.2 million people that are amputees.

It's not like we're making cell phones or calculators where you just continue to drop the price down because of volume.

It's a small industry and because of that there is very little fundamental research, so we are generally late to adopt things. Electronics and composite materials and all the things that make up high tech today have been around for a long time, but it's only been in the last five to 10 years it was applied into this portion of the business.

What is the state of the collaboration between the medical and scientific community?
Harman: There is a fair amount of collaboration in centers (such as) the Mayo Clinic, the Cleveland Clinic, Johns Hopkins, Stanford...There are a number of people who are interested, and have established gait labs as an example, to study the gait and how prosthetics impact that. That's adequate. I think what we're missing is the ability to develop good clinical claims...because again there aren't that many people. In a traditional drug study, a drug company might study 5,000 patients or more, and if we do a C-Leg study, we're lucky to get 20 patients.

What percentage of that 1.2 million amputees would go high tech, would have devices like the C-Leg?
Harman: In total, it's probably less than 10 percent of the population that would receive high-tech componentry. To give you an example, the C-Leg in the United States is a product that is generally recommended for mid- to high-active patients, and there are only about 8,000 of those a year that would be an above-the-knee, active amputee.

And we are taking about products that, from what I've read, are in the $40,000 to $60,000 price range?
Harman: That's a bit misleading. The products themselves are only a percentage of that. A $40,000 device would include all the components; the socket, which has the interface between the residual (limb) and the componentry; and the prosthetist's time. They can be that expensive, but it's a part of a total package.

Are we still in the first generation, or we are in a second generation of chip-based technology for the prosthetics?
Harman: As far as lower extremity is concerned, we're moving into the second generation. Now in upper extremity, which doesn't get a lot of press...myoelectric upper-extremity componentry has been around a long time. While (those devices) didn't use chip technology, they did use micro motors and batteries and power supplies and electrodes, so that was kind of a frontrunner. Actually, upper extremity really started the whole high-tech push.

How have the chips altered the design and use of the products?
Harman: Much like just about anything else where chip technology is applied today, it's basically making decisions faster. In this case what chip technology has allowed us to do is...very quickly monitor the terrain and the speed of the wearer and make adjustments, so that in essence the patient is in a much safer mode. Prior to chip technology, just to go down the stairs, typically an amputee takes one step at a time, and it would be good leg first and then they'd drag the prosthetic device behind them. With chip technology, an amputee goes down the steps one foot after another much like you or I would. The decision process is taken out of it (for the amputee), and it's made in the leg itself.

What are the limitations of something like the C-Leg and these higher-end devices? How reliable are they, what is their life span?
Harman: I don't think that the technology has a limitation. I think it's cost-return, cost-benefit that's the limiter at this point, because again we are not producing that many units. It's not like we're making cell phones or calculators where you just continue to drop the price down because of volume.

What's the next big step?
Harman: The next big step is probably going to be motorized or power-assist (additions). Today you're under your own power--there's a battery that drives the electronics, but it's your leg that powers the movement of the device. In the future there's some technology around

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Exciting News

I have been following the C-Leg for a couple of years now and am excited to see it mentioned here. My son is high-level amputee (hemi-pelvectomy) and I would be very interested in hearing state of the art news about advances in prosthetics - particularly in the myelectric and bone implantation areas - as these relate more closely to my sons amputation.

[Fray9]

Sadly

Sadly because prosthetics is such a small industry a lot of potential research areas have to be neglected.

Currently there is synthetic muscle that could afford a prosthetic limb more natural and a fuller range of movement (though they're not very strong yet), as well as power systems that can create electricity from sugar compounds like the glucose in the human bloodstream. Then theres the synthetic skin that was developed with dozens of tactile sensors per square inch that is still sitting on a shelf from 5 years ago. Also recently theres been breakthroughs in integrating systems with actual nerves in the motor center of the brain. Already there have been experiments where monkeys could actually feed themselves banannas with only a robotic arm controlled by thought.

But these areas of research cant even be considered yet in the prosthetics world and are only marginally being looked into in the world of robotics mainly because of lack of funding.

Its a bit of a catch-22 unfortunately. They cant afford cutting edge research because they dont make enough money off prosthetics sales to afford it. Out of a genuine desire to help people they raise the prices of the devices to fund research but the higher prices only results in reduced sales because the amputees cant afford it either.

If you really want to help this realm of research, do fund raisers and petition the government and companies to sponsor this research field which is struggling far behind where they could be today.

Guinea Pig?

My son was lost his right leg above the knee on June 27th as a result of a shark attack in Florida. I read with interest your article and hopeful that Craig will benefit from the new technology that is being developed. The article stated that it is difficult to find amputees to test the new products on. I may be speaking out of turn but I would think that Craig would love to test market any new technology.

[jaytmoon]

Prosthetics go high tech

This is wonderfull technology. Now if it could just be made to look more like natural skin instead of a oversized turtleneck!

[legs42]

I am located in West Sacramento,I am a bi-lateral amputee [both legs above the knee] I would be happy to assist any research program,I now have two c-legs[6 months].I have problems putting them on.my thighs have gotten larger since the last fitting.Please free to contact me if need be west sacto located in calif thank you William Schwab