Responses to - Heat issues in sockets

Responses to - Heat issues in sockets

Steve Middleton

9/28/2011

Thank you to those who took the time to respond.
The response has mostly been about patients dealing with sweat /perspiration
issues, thankfully this has not been a concern for me. When I do get any
perspiration I am easily able to drain it through the suction socket valve.


Posted Question -

To: <Email Address Redacted>
Subject: [OANDP-L] Heat issues in sockets

I am in my early 50's for 10 years I have been a very active above knee
amputee.
I presently use a heat moulded thermoplastic suction socket, skin fit with
no liner. To don the socket, I use the dry pull sock method. I do not
require a belt even during high activity.

I cycle both road and mountain bike's extensively and for the most part have
very few issues on longer rides. Perspiration has not been a concern because
I can drain the socket of moisture through the vacuum valve. Extreme heat,
for example a climate of plus 86 deg F (30 deg C) and humidity does create
great discomfort and redness then some swelling. Thus cooling is an issue.

What ideas or suggestions do any of you have for a way to keep this socket
cooling during an activity period?
Is there possibly some new device / materials for such an application?

I do not wish to start wearing a sock or liner and realise some of these now
have Thermodynamic properties.

Steve Middleton Ak amputee

 - - Responses were......

Being from Florida I'm amused by your Extreme heat of 86, where do you
live, the north pole?
The affect of the external environmental temperature is primarily on the
rest of your body, not just the residuum. The higher the outside temp and
humidity, the more difficult for the body to maintain its normal of 98.6.
The body is an efficient heat producing engine, the more activity the more
heat must be dissipated. We keep cool by perspiration evaporating on the
skin. The efficiency of this system depends on the surrounding temp and
humidity relative to our core temp.
Unfortunately the materials we use to fabricate prosthetic systems are good
insulators. The amputation results in a major decrease of skin surface
area, couple this with the insulative properties of the prosthesis and its
no wonder the residuum feels hot and overall perspiration increases.
Theoretically, the way to solve the problem is to design and fabricate the
prosthetic interface of a material that is heat conductive, not insulative.
This means metal. Most metals are highly reactive with the body's skin,
salts, electrical charge, and pirspiration. Stainless and titanium come to
mind as being good candidates. Aluminum may also be a candidate if an
applied protective coating can be found that doesn't lessen heat
conductivity.
With the metal interface internal surface maintaining suspension vacuum,
socket shape, and weight transfer, it is a simple task to design the outer
interface surface and the rest of the prosthesis to dissipate the internal
heat of the residuum.
For high activity, or extreme external temps, an auxiliary cooling system
may be added, maintaining whatever residuum temp the wearer desires. This
removable system must be part of the initial design and fabrication.
So far this has been rather simple and straight forward. Now the hard part.
How deep are your pockets? Is the problem really distressing enough to
warrant these costly solutions? Finding an innovative prosthetist able to
handle both the fitting of the prosthesis and managing the actual design and
fabrication of the overall system.
Good luck
Morris Gallo, LPO
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Mr Feldman was good enough to forward two articles - Which I will review and
post the outcome.
 - Types of Thermoplastics - Prosthetic Primer: Materials Used in
Prosthetics Part I
 - Kinematic and Kinetic Comparison of the Conventional and ISNY Above-Knee
Socket

Hi Steve,
OK. Everything is fine except the heat. You have a thermoplastic liner so
that means it was made with a flat or cone sheet of thermoplastic. Just
going over the basics. A socket made with resin sets with a chemical
reaction and is a thermosetting plastic socket. The more layers of
plastic, or resin, or thickness of a socket will retain heat.
Attached is some information for you, and you may bring it to your
prosthetist to discuss your options.
Let him know you seriously want to have or attempt some solution, and that
you will make the financial commitment for his time (he has costs and time
just like you) if he will provide or refer a O and P lab that will provide
you such a socket. The ISNY system is a complete new system, total contact
and suction. There are some new flexible plastics available since that
article was written for longer lasting activity. As long as your sensible
and the socket is not too thin I think you will be happy.
Steve, I do not have all the answers but I hope this helps.
Rick Feldman, CPO (abc/usa)
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Hi Steve,
Recently at a conference in Vegas we learned about brimless AK sockets which
may help for the bike riding comfort. I live here in Arizona and we would
jump up and down for 86 degree days. Perspiration is an issue all over. I
have heard about some people having success with antiperspirant creams, we
use liner liner sock with success for BK's, not so much AK's.

Joseph S. Pongratz, CPO, FAAOP
President, Director of Clinical Services Pongratz Orthotics and Prosthetics,
Inc.
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