April 24, 2009 Earlier this week we looked at developments in low-cost prosthetics, but at the other end of the spectrum, advanced prosthetic devices like Ossur's recently announced second generation POWER KNEE are opening up new frontiers in the field. As the world’s first motor-powered artificially intelligent prosthesis for above the knee amputees, the POWER KNEE is designed to enable daily activities without having to think about movement. Something most of us take for granted.
The POWER KNEE
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Ossur introduced POWER KNEE in 2006 in a partnership with Victhom Human Bionics. This bionic prosthetic - which has to date been used largely in the U.S Department of Defense and the Veterans Healthcare Administration - replaces the muscle activity required to bend and straighten the knee which allows the amputee to walk in a powered gait, climb and lift the body. It even lifts the heel off the ground, providing sufficient toe clearance during swing to prevent stumbling. The POWER KNEE works as an integrated extension of the limb, and when walking on level ground the user is gently propelled forward allowing greater distances to be covered with much less effort, according to Ossur. On stairs and inclines the knee actively lifts the user up the next step, foot over foot in a natural and secure movement.
“The new second generation POWER KNEE delivers significant improvements in terms of weight, height and noise reduction as well as in power autonomy and ease of use," says POWER KNEE inventor and COO of the Biotronix business unit for Victhom, M. Stéphane Bédard.
How it works
Advanced torque and accelerometer sensors are utilized to allow the amputee to control the walking in an unconscious manner, whilst the prosthetic provides the support when contact is made by the foot with the ground. The new improved artificial intelligence operates in layers to manage the human-system interface. This allows the prosthesis to focus on providing safety, system stability and system adaptability. According to Ossur, the user just walks and the prosthetic does the rest.
The motion of the prosthesis is made possible by lifting the thigh muscle. This generates power relative to the users needs, catering for movements requiring specific power management like walking up or down stairs or inclines, and sitting or standing.
Ossur and Oscar Pistorius
As an aside, you may remember all the kafuffle in the media in January 2008 about the bilateral amputee and world champion sprinter Oscar Pistorius who was banned by the International Association of Athletics Federations (IAAF) from competing against able-bodied runners on the grounds that his prostheses (similar to the POWER KNEE) give him a technical advantage. A remarkable athlete, Oscar had broken his own world record 27 times and is the first ever Paralympian to win Gold in each of the 100, 200 and 400 meter-sprints. On May 16, 2008, that ruling was overturned and Oscar’s dream to compete against able bodied runners has been restored.
Ossur is currently working with the rehabilitation team of Walter Reed Army Medical Center to provide the second generation of the POWER KNEE to patients. A full commercial release is expected by 2010.
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