XT9 - Energy-Storing Prosthetic Knee (ESPK)
The "XT9" Energy-storing Prosthetic Knee (ESPK)
Designed for High and Extreme Activity Amputees
Featuring Adjustable "Quad Mimic" and "Extension-Assist" Control
Manufacturer: Symbiotechs USA
There have been significant advancements in prosthetic devices that can greatly improve the health, performance and the activity level of above knee (AK) amputees. New energy-storing prosthetic components such as the XT9 "Energy-storing Prosthetic Knee" (ESPK) provides a flexible "stance," can absorb shock, store and release energy.
A prosthetic knee that can store and release energy can be extremely beneficial to Above knee (AK) amputees. One of the most important goals of an amputee following a transfemoral amputation is to return to the highest functional level of ambulation possible. Active or extreme athletic amputees demand more than a minimum functional level of ambulation from their prostheses. These amputees have the additional goals of being able to ski, surf, jump, climb and participate in other active sports. The demand for a prosthesis capable of a higher level of performance demanded the invention of an energy-storing prosthetic knee.
Similar in function to an energy-storing prosthetic foot (ESPF), the SymbiotechsUSA Energy-storing Prosthetic Knee (ESPK) was designed to provide upper leg muscle functionality by attempting to mimic the quadricep and hamstring muscles of the thigh. This is accomplished by using the combination of an energy-storing "coil-over" spring surrounding an air-filled shock absorber. Both the spring pressure and air pressure are user-adjustable to achieve the desired amount of shock-absorbing energy return, as well as lower leg swing extension. Working in tandem, the adjustable coil spring and air-shock provide the amputee with a variable flex-stance.
The energy-storing knee flexes and absorbs spring energy during loading, then acting as an elastic spring the XT9 returns a portion of the input energy to the amputee. The efficiency and user-adjustability of the energy-storing spring-air combination provides increased impact absorption by the prosthetic device and delivers less harmful impact to the musculo-skeletal system. Until the appearance of the energy-storing knee, the musculo-skeletal system itself had to absorb and dissipate large amounts of energy detrimental to the amputee, negatively affecting hip and knee wear, and inducing possible spine compression damage. The XT9 energy-storing prosthetic knee allows the amputee to distribute a balanced level of energy absorption between the prosthetic limb and the sound limb.
The energy performance criteria of energy storage, energy
return, dissipated energy, overall efficiency and total energy were maximized in
the XT9 design. SymbiotechsUSA engineers met and exceeded these
challenges by precision machining the waterproof, titanium XT9 energy-storing prosthetic knee
military "mil-spec" specifications. With SymbiotechsUSA release of
the "XT9" energy storing knee, they stand alone in the prosthetics industry by
providing amputees with extreme energy storage and return prostheses.