VA Research and Development
University of Washington, Department of Bioengineering

Click on the image above to view an
animation of the
Pump It Up! Socket

Amputee Treatment Center has designed, developed and patented a revolutionary new prosthetic socket design for people who wear lower extremity prosthetic devices. The Pump It Up! socket design is the first prosthetic socket that is adjustable with air and enables the wearer to adjust the fit anytime. Our socket design incorporates an inflatable custom-made bladder sandwiched between an inner and outer socket, which allows the wearer to add or remove air with a small hand-held pump, as required to maintain comfort and add cushioning.

After 16 years of research and development, two U.S. Patents were awarded to Mr. Michael Love and a third Canadian patent was issued in 2005. During the patent searches, we learned that there have only been 25 patents dating back to 1860 that involved a pneumatic socket design, however none have been manufactured successfully due to the inherent difficulties in designing the system. Although many new components and materials have been developed, the basic design of a prosthetic socket has remained unchanged for decades.

Wearing an artificial limb can be very difficult and affects every aspect of daily living. Since artificial limbs are worn externally over the remaining limb, optimum comfort has always been desired but not always achieved. Most amputees experience volume changes every day, which cannot be accommodated in a traditional socket design with rigid walls. A daily change in volume is very similar to your hands and feet swelling at the end of the day. Therefore, a prosthetic device that allows the wearer to continually adjust the fit of their artificial limb is ideal and this is exactly what the Pump It Up! socket design accomplishes with air from a small hand-held pump.

In this socket design Amputee Treatment Center has addressed the needs of the amputee based on our thirty-four years of experience in the field of orthotics and prosthetics. The inflatable prosthetic socket helps solve the fitting problems faced by most amputees. The prosthetic socket is the part of the artificial limb that the amputee wears over the residual limb. Because it must bear the weight of the individual, the socket is generally quite rigid and unforgiving. It is for this reason amputees find wearing an artificial limb a somewhat uncomfortable endeavor.

The Pump It Up! socket design involves a custom-made bladder sandwiched between an inner and outer socket. The bladder is inflatable through a valve located on the outside of the prosthesis, so there is no need to remove the prosthesis to adjust the fit to any comfort level desired. The inner sockets custom design will determine where the bladder comes in contact with the residual limb. We have fabricated our Pump It Up! socket design incorporating traditional socket designs such as PTS and PTB for below-knee amputees and QUAD and narrow M-L for above-knee amputees. We have fit above-knee amputees with the narrow M-L socket and the Pump It Up! socket design and no additional suspension or even a suction valve in some cases is required. The bladder not only suspends the prosthesis but adds additional cushioning and rotational stability as well.

With both below-knee and above-knee sockets the openings are created in the inner socket that allow the bladder to migrate through the openings and contact the insert liner or the stump sock in the case of a hard socket. The liner can be from any manufacturer, locking or cushion and any thickness. The openings are usually placed in the weight bearing areas. Because the bladder fits circumferentially, we have the option of placing the openings anywhere within the socket. A small valve through the outside of the prosthesis allows the wearer the freedom to add or remove air from the bladder to adjust for comfort, as well as fit without removing the prosthesis. There are so many variations of inner sockets and liners that fitting possibilities are infinite.

The inner and outer sockets are roughly the equivalent in thickness of a conventional socket. The air bladder is .060 thick and adds about 100 grams of weight to the prosthesis. The hand-held pump is included with the socket.


Comparison to Present Products

In reviewing what others have described as an "air cushioned" approach to below-knee socket design, our system differs in significant ways. A double lamination technique allows us to determine where the eventual primary weight bearing areas will be placed. For the amputee to simply put on an "air sock," pump it up with air and expect it to be usable is incorrect. What makes this unworkable is that it does not provide for rotational stability, which is a must if the amputee is to control his prosthesis. The socket must have a contoured interface that closely matches the contours of the amputation, if stability is to take place.

Inflatable pads of various sizes are available and may answer one need by allowing an amputee to place the pad in his socket and inflate it with air pressure. But there is only a small area to be affected by this inflatable pad. Inflating it could cause too much pressure on the opposite side of the residual limb where the pad is not worn, since inflating the bladder means squeezing the residual limb to the other side of the socket. In the Pump It Up! socket design the air bladder becomes an integrated part of the prosthetic socket design. The weight bearing areas are individually determined for each amputee. This is where the bladder comes in contact with the residual limb. This allows the amputee to inflate or deflate the bladder and adjust the fit to their individual needs. Thousands of prosthetic sockets are replaced each year simply because they can no longer be adjusted to fit comfortably.

With a socket system that the amputee can adjust for comfort, they will get more use out of their prosthesis for a longer period of time thereby reducing health care cost.


Insurance Coverage

The Pump It Up! TM is a covered product for individuals with Medicare, Preferred Care and Independent Health with appropriate documentation. The charge for the Pump It Up! socket is $4,202.50, which includes the fabrication process and the bladder system.



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