|
University of Washington
Department of Bioengineering
SANTOSH ZACHARIAH, RESEARCH ASSISTANT PROFESSOR
August 25, 2000
Dear Michael,
RE: Pump It Up Socket
Further to your request, below is a brief description of my understanding
of the Pump It Up socket system, and the value it offers to amputees.
The Pump It Up Socket is a custom-made artificial leg (prosthetic) socket. Its primary use is in persons with amputation/limb-loss
below the knee (trans-tibial), though it can also be used by above the knee (trans-femoral) amputes. It is different
from standard prosthetic sockets in that the shape and volume of the socket can be continuously controlled by the
user. The basic principle of design is that the amputee/user can manually control an air pump that pumps into or
removes air from an expandable bladder within the socket. As the bladder expands/contracts it changes the shape
and volume of the socket. The amputee/user can only control the amount of air added or removed. His/her prosthetist
must decide the shape and placement of the regions where the bladder pushes on the skin.
The Pump It Up Socket has three unique features. 1) The air bladder used to control the shape and volume is custom-made
for the individual amputee. All other similar devices rely on off-the-shelf components. 2) The air bladder is an
integral part of the socket design. In other devices the air bladder is attached to the inside of the socket wall.
3) The custom-made bladder and integral socket design together allow the prosthetist to precisely control the shape
and location where the bladder pushes on the skin of the residual limb. This level of control is not available
with off-the-shelf bladders attached to the inside of the socket wall.
Devices like the Pump It Up Socket that control the shape and volume of the socket can be of use to amputees that
experience change in volume of the residual limb during the day. All amputees experience some degree of daily volume
change. This is commonly accommodated by changing the thickness of the sock the amputee is wearing. Volume control
by an air bladder may be warranted if the sock cannot provide adequate volume change, or the amputee cannot take
off and put on the socket every time the sock needs to be changed.
As a researcher of interface mechanics within lower-limb prosthetic sockets, I personally believe that the factor
that most affects the day-to-day quality of socket fit is the continuously changing volume of the residual limb.
Investments in devices that maintain the quality of socket fit can be more cost-effective than compensatory adjustments
to other parts of the artificial leg.
Yours truly,
Santosh Zachariah
Room 341-C AERL Building
Box 352255 Seattle, Washington 98195
(206) 685-3488 FAX: (216) 543-6124
szach@u.washington.edu |
http://faculty.washington.edu/szach
|
