Bionic Leg for the Commercial Market

Jay writes "I thought you may be interested in this crazy-cool fully powered bionic knee called the Power Knee. It's made by Victhom, a French-Canadian company and will be marketed by Ossur, an Icelandic prosthetics company and one of the biggest prosthetics companies in the world. You may have seen them in the news lately with their Rheo Knee or rheomagnetic computer controlled knee. This new Power Knee takes it to the next level with full active power. Supposedly it will allow people to walk up stairs and the like. Here's the link to Ossur's Power Knee website with photos and video, and to Victhom's website. Cool video, amazing device."

Comments

power consumption

[phloydphreak]

The article states the the prosthetic generates its own power, probably a kinetic power generator. How much power can such a device output, especially to run an embeded AI which determines the movement of the limb. Does the limb eventually run out of power (reducing it back to a normal prosthetic)? Such as, if the limb is not used for an extended period of time? The very design of it is ingenious though, and I would not doubt that they have made the system fully self-sufficient. Very cool.

A useful feature that is missing

[David_Shultz]

A feature that would be very useful, though I didn't see it mentioned anywhere on the site, would be the ability to "punish" the knee for making an error. Most learning algorithms work by having a teacher tell them what sort of actions/decisions were right or wrong. With this system, there is probably some sort of hardcoded teacher, which is not necessarily the best way to do things -the best judge of what you want your bionic leg to do is probably yourself, and not a programmer somewhere. For example, if your leg starts to give way as youre walking up stairs, forcing you to catch onto the rail to prevent serious injury, you should have the ability to say, basically "bad leg!". By pressing the appropriate button, you would teach the AI that it made a mistake, and it would modify itself as necessary. A similar system might be useful for telling the system when its doing a good job, perhaps a dial that simply represents the users satisfaction.

Re:i don't really get it

[multiplexo]

Above knee (trans femoral) amputees have a harder time of walking with most prosthetic knee joints because they have to learn to modulate the swing of their leg using the muscles in their thigh, glutes and lower back. Eventually many of them learn to do this well enough so that you can't tell that they are wearing a prostheses. However this is very fatiguing. The Ossur C-leg was a major advance for AK amputees because the microprocessors could modulate the swing of the lower portion of the leg, making it swing farther for a faster gait and not so far for a slower gait.

However for climbing up and down stairs AK amputees have a harder time, even with a smart knee such as that in the C-leg because they don't have the muscles to modulate their gait and the muscles through the knee that help you go up and down slopes and stairs. Going up and down stairs with a BK amputation (trans-tibial) is also difficult due to the loss of the muscles and joints in the foot but is manageable, for an AK amputee all of the work in going up and down stairs has to be done by the remaining leg, which gets tiring very quickly.

I've met a lot of AK amputees (I'm a BK amputee) and this leg will be a huge advance for them, now we just need to get their insurance companies to pay for them, which isn't easy because a sophisticated AK prostheses can end up costing 50 or 60k when all is said and done.

Longevity of artificial joints

[spineboy]

Yes, 15 years is the lifetime that we're seeing, on average, but remember that these were put in 15 years ago! The plastics (ultra high molec weight, highly cross linked poly) are supposedly much better now, and should last longer than the 15 years.

Hips and knees are diferent - knees are currently limited to metal on plastic, whereas hips can come in a variety of composites. Recently, metal -metal hips, and ceramic hips have been making a go around - they are supposed to have 10 times less wear than the plastic-metal hips.

TO be honest 15 years is very good. Most people really dont need a total joint arthroplasty (artificial joint) until they are over 50 years of age. One revision surgery should last them until they are around 80 - which is currently a little higher than the average lifespan of most people.

Several factors have an effect on the lifetim of these artificial joints - younger, heavier people wear theirs out faster , than older lighter people. However, being overweight probably was a MAJOR contributing factor for the reason that many people need these in the first place.