FW: Flexible socket for Trans-tibial -RESPONSES
Randy McFarland
Description
Collection
Title:
FW: Flexible socket for Trans-tibial -RESPONSES
Creator:
Randy McFarland
Date:
12/30/2004
Text:
ORIGINAL POST:
Hi Listmembers,
I can understand that a soft flexible brim might be indicated for
a TT residual limb with significant redundant tissue. I can also see the
benefits for a bony residual limb if appropriate fenestrations are make
in the outer hard socket.
Are there any reasons/benefits to making a flexible inner socket
for a TT if no reliefs or fenestrations are make in the outer socket?
I'll post responses.
Randy McFarland, CPO
Fullerton, CA
RESPONSES:
A flexible inner liner allows for padding to be added between the liner
and frame. Also, the liner can be removed and adjusted or even replaced,
without effecting the outer frame. The locking mechanism can also be
serviced this way.
I think it's good for
1) If there is a considerable off set needed
2) If you are using the Endolite connectors
3) Billing
I really don't see why they put fenestrations in them. It would seem the
socket wasn't designed right---but I could be wrong. I have never done
it.
I guess you could make a case for bulbous shapes but I guess that's what
you mean by redundant tissue.
You could utilize a flexible inner socket to assist in making fit
changes, especially in a socket where a silicone gel liner is used, like
placing pads to tighten the fit between the flex socket and the rigid
frame. You could argue that a pelite liner would serve the same purpose
and for less expense but it is one possible application.
Not for the amputee, it becomes a double-walled hard socket, with a
little more weight for an extra L-code.
You already knew that, I do like that big, fancy word for window
though, can't wait for the next generation of Microsoft Fenestrations to
hit the desk tops.
Thanks, I can always use a chuckle.
If there is edema or limb fluctuation a flexible liner may be removed to
accommodate this edema but I think this is another code like total
contact and test sockets that are abused where they are not really
needed just to increase profits. I do beleive flexible sockets are
beneficial for Transfemoral amputees.
To answer your question = Are there any reasons/benefits to making a
flexible inner socket for a TT if no relief's or fenestrations are make
in the outer socket?
ANSWER: The term flexible is not synonymous with elastic. I have
found that amputees have reported benefits of using a thermo-elastic
material inner-socket [erroneously termed flexible] to provide [1] a
softer/forgiving/cushion feel to the amputees residual-limb, [2]
greater coefficient of friction that assists in suspension, [3] the
ability to make socket adjustments to the rigid supporting socket
(external/frame) without affecting the surface of the inner socket,
[4] if an HSI system is utilized (Hypobaric Suspension/cushion
Interface- pin-type suspension system), the attachment mechanism is
connected to the inner socket and therefore is completely serviceable -
including the ability to replace the mechanism should it be damaged to
the degree of requiring replacement; should there be significant volume
reduction with consequential loss of weight bearing support, and
following refitting adjustment maximizing - the master model can be
rectified, the same socket heated and reformed over the revised model,
and the resulting space between the inner and outer sockets can be
injected with various materials to fill the void, and re-establish an
intimate, stable fit.
Must keep in mind that the flexible socket is not applicable to
this approach - only the thermo-elastic material seems to work.
I used it once on a very active tt that wanted cut
outs but we ended up with such a good fit he didn't
require it. However the benefit we did see with him
was the increased durability of his silicone liner and
knee sleeve, because the proximal edges were left
longer than the external frame thus a softer region of
contact with the delicate liner and knee sleeve.
As you know there are always other applications for devices in our
creative kind of work. Following are some uses that I have seen the
flexible inner liner used for:
A) Volume change accommodation
B) Hygienic purposes - It can be removed and washed thoroughly
C) Suspension - The patient can put it exactly in place on the
residual limb, then guide it into place in the prosthesis to engage a
suspension catch or lanyard like the Coyote.
D) The Slip Socket concept to relieve abrasion or spring loaded
from below to reduce impact.
We find that the flexible transition also aids in prolonging the life of
the liner.
I can't wait to read the responses that don't say, pad the bill or
creative billing.
This should be entertaining.
If there is no visible reasons for the flexible inner socket, the only
reason I would add the interface is if the patient was expected to have
volume changes that the inner socket could be used instead of apply
shims to the hard socket. I know this sounds like a big waste of time
and materials. I personally only add the interface to a TT if boney
areas are in concern or a history of wear is present. Why add the weight
if you don't need it?
It is particularly helpful when you want to make adjustments to the
inside of the socket without changing the coefficient of friction
interacting with your limb interface. For example, I commonly add a
soft pad to increase pressure in the interosseus space to further
relieve a sensitive anterior distal tibia. If I add that to the inside
of a hard socket without a flexible insert I've introduced a new
material with a different coefficient of friction than the socket
surface. The change in friction from the socket to the pad will
introduce new shear forces that will act upon the interface, (sheath,
sock, silicone liner, etc), and transmit to the skin of the residuum.
If instead that pad is added in between the soft flexible socket and the
laminated socket, the flexible socket takes the shape of the added
material, but the surface material that interacts with the interface is
unchanged. In this fashion, the socket is nearly as easy to adjust as a
pe-lite insert, allowing for pressure redistribution without new,
unwanted or unintended shear forces. And heck, plastic is easier to
clean.
I've heard of other prosthetists using them as test sockets and
volume control devices as well.
Granted, no studies have been done to support nor deny the effectiveness
or medical necessity of these suppositions. I'm sure many folks out
there think that adding flexible socket inserts to BK/TT prostheses
without fenestrations is just a way to add another code to an already
expensive prosthesis. I suggest that there is some value in the
addition. Anyone looking for a research topic?
Hi Listmembers,
I can understand that a soft flexible brim might be indicated for
a TT residual limb with significant redundant tissue. I can also see the
benefits for a bony residual limb if appropriate fenestrations are make
in the outer hard socket.
Are there any reasons/benefits to making a flexible inner socket
for a TT if no reliefs or fenestrations are make in the outer socket?
I'll post responses.
Randy McFarland, CPO
Fullerton, CA
RESPONSES:
A flexible inner liner allows for padding to be added between the liner
and frame. Also, the liner can be removed and adjusted or even replaced,
without effecting the outer frame. The locking mechanism can also be
serviced this way.
I think it's good for
1) If there is a considerable off set needed
2) If you are using the Endolite connectors
3) Billing
I really don't see why they put fenestrations in them. It would seem the
socket wasn't designed right---but I could be wrong. I have never done
it.
I guess you could make a case for bulbous shapes but I guess that's what
you mean by redundant tissue.
You could utilize a flexible inner socket to assist in making fit
changes, especially in a socket where a silicone gel liner is used, like
placing pads to tighten the fit between the flex socket and the rigid
frame. You could argue that a pelite liner would serve the same purpose
and for less expense but it is one possible application.
Not for the amputee, it becomes a double-walled hard socket, with a
little more weight for an extra L-code.
You already knew that, I do like that big, fancy word for window
though, can't wait for the next generation of Microsoft Fenestrations to
hit the desk tops.
Thanks, I can always use a chuckle.
If there is edema or limb fluctuation a flexible liner may be removed to
accommodate this edema but I think this is another code like total
contact and test sockets that are abused where they are not really
needed just to increase profits. I do beleive flexible sockets are
beneficial for Transfemoral amputees.
To answer your question = Are there any reasons/benefits to making a
flexible inner socket for a TT if no relief's or fenestrations are make
in the outer socket?
ANSWER: The term flexible is not synonymous with elastic. I have
found that amputees have reported benefits of using a thermo-elastic
material inner-socket [erroneously termed flexible] to provide [1] a
softer/forgiving/cushion feel to the amputees residual-limb, [2]
greater coefficient of friction that assists in suspension, [3] the
ability to make socket adjustments to the rigid supporting socket
(external/frame) without affecting the surface of the inner socket,
[4] if an HSI system is utilized (Hypobaric Suspension/cushion
Interface- pin-type suspension system), the attachment mechanism is
connected to the inner socket and therefore is completely serviceable -
including the ability to replace the mechanism should it be damaged to
the degree of requiring replacement; should there be significant volume
reduction with consequential loss of weight bearing support, and
following refitting adjustment maximizing - the master model can be
rectified, the same socket heated and reformed over the revised model,
and the resulting space between the inner and outer sockets can be
injected with various materials to fill the void, and re-establish an
intimate, stable fit.
Must keep in mind that the flexible socket is not applicable to
this approach - only the thermo-elastic material seems to work.
I used it once on a very active tt that wanted cut
outs but we ended up with such a good fit he didn't
require it. However the benefit we did see with him
was the increased durability of his silicone liner and
knee sleeve, because the proximal edges were left
longer than the external frame thus a softer region of
contact with the delicate liner and knee sleeve.
As you know there are always other applications for devices in our
creative kind of work. Following are some uses that I have seen the
flexible inner liner used for:
A) Volume change accommodation
B) Hygienic purposes - It can be removed and washed thoroughly
C) Suspension - The patient can put it exactly in place on the
residual limb, then guide it into place in the prosthesis to engage a
suspension catch or lanyard like the Coyote.
D) The Slip Socket concept to relieve abrasion or spring loaded
from below to reduce impact.
We find that the flexible transition also aids in prolonging the life of
the liner.
I can't wait to read the responses that don't say, pad the bill or
creative billing.
This should be entertaining.
If there is no visible reasons for the flexible inner socket, the only
reason I would add the interface is if the patient was expected to have
volume changes that the inner socket could be used instead of apply
shims to the hard socket. I know this sounds like a big waste of time
and materials. I personally only add the interface to a TT if boney
areas are in concern or a history of wear is present. Why add the weight
if you don't need it?
It is particularly helpful when you want to make adjustments to the
inside of the socket without changing the coefficient of friction
interacting with your limb interface. For example, I commonly add a
soft pad to increase pressure in the interosseus space to further
relieve a sensitive anterior distal tibia. If I add that to the inside
of a hard socket without a flexible insert I've introduced a new
material with a different coefficient of friction than the socket
surface. The change in friction from the socket to the pad will
introduce new shear forces that will act upon the interface, (sheath,
sock, silicone liner, etc), and transmit to the skin of the residuum.
If instead that pad is added in between the soft flexible socket and the
laminated socket, the flexible socket takes the shape of the added
material, but the surface material that interacts with the interface is
unchanged. In this fashion, the socket is nearly as easy to adjust as a
pe-lite insert, allowing for pressure redistribution without new,
unwanted or unintended shear forces. And heck, plastic is easier to
clean.
I've heard of other prosthetists using them as test sockets and
volume control devices as well.
Granted, no studies have been done to support nor deny the effectiveness
or medical necessity of these suppositions. I'm sure many folks out
there think that adding flexible socket inserts to BK/TT prostheses
without fenestrations is just a way to add another code to an already
expensive prosthesis. I suggest that there is some value in the
addition. Anyone looking for a research topic?
Citation
Randy McFarland, “FW: Flexible socket for Trans-tibial -RESPONSES,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 2, 2024, https://library.drfop.org/items/show/224146.
