Silicone and stiffness
Karl Montan
Description
Collection
Title:
Silicone and stiffness
Creator:
Karl Montan
Date:
11/17/1997
Text:
Regard. partial foot amputation
Karl:
I am a partial foot amputee (Lisfranc) in Sweden with a long
experience as service consumer and have had this dialogue with
Michael in Germany. If you are involved in these problems and want to
join the discussion, you are welcome to me or
Michael Maier <maier.ortho@t-online.de >
<URL Redacted>
Michael:
I am born in 1964, my profession is orthopedic shoe-technician, which
is an indepentent working area here in Germany (indepentend from the
orthopedic technicians)
I have, together with my father, a workshop here in Karlsruhe, 140 km
south of Frankfurt. Our working areas are all kind of foot ortheses,
orthopaedic shoes, insoles.
Karl:
For the moment I will only mention one question.
I have - as one of the very few in the Scandinavian countries - tried
to use a siliconprostheses for my Lisfrancstump. It was just a
siliconfoot put on my stump without any other applications. It was
not bad but as I since some years have a thight and stiff prostheses
with a supporting splint on the front of the leg, which
is acceptable and never gives soars, I prefer this old one. The
prostheses I thus am used to, takes up a lot of pressure through the
splint.
It has surprised me that in literature and contacts with friends
outside the Nordic countries, it seems as the siliconprosthesis are
very common and also appreciated. How is it in Germany ? Do you have
any experience ?
Michael:
In my opinion silicon feet are too soft. It has the full forces on the
front part of the foot stump. We use normaly a modified type of the
ortheses you wear.
That means, we use also an supporting splint on the leg, but in
different lengths and different stiffness. It depends from the
amputee, if he is very active and, of course, of his weight. The
splint itself is build up in a sandwich technologie, with glas fibre
or thermoplastic material. So we can transfer the load up to the leg
and release the footstump in the front part, without giving an
uncomfortable feeling of pressure to the leg. The forefoot is
made out of soft material, which gives more comfort and makes a
dynamic walking
possible.
We could not reach all this mechanical effects with an simple silikon
foot.
There might be people who find them sufficent, but I prefer the other
kind of ortheses.
Karl:
. Are you speaking about a silicon foot with supporting splint ?
Michael:
No, we are using two types of foot prosthesis. One is made of a
polyethylen foam, with little weight and flexible for very active
persons. Another is made of cork and one layer of flexible rubber,
which gives a feeling of more stability than the foam
foot for the fore foot amputee. Silicon has more weight and is much
more expensive.
Karl:
In Sweden we have tried to find a compromise between a quite stiff
splint, which don´t allow any movement of the ankle joint, and an
insert
without supporting splint and full movement of the joint. Experiments
are going on with some disappointments.
When you mention the stiffness of the supporting splint, I have the
impression that you are able to vary the stiffness, which may give
more or less of ankle movment. If so, don´t you have difficulties
with breaks in the material which is bending for every step ?
Michael:
Yes, that was a big problem. The normal materials like polypropylen or
polyethylen will break very fast. We have tested a special durable
elastic thermoplast, which does not break under load. With this
material we get only a half stiffened ankel joint. It is a
thermoplast which is very flexible and with a melting point around 90
degree celsius, which is much lower than the normal used thermoplasts.
We use it for longer fore foot stumps, up to the Lisfranc
line. For shorter stumps it depends, if the stump can bear the higher
load compared to a normal stiffened ortheses. We use this material
since about 3 years, and up to now we have very good experiences.
These orthesis are much more comfortable than the totaly stiffened.
_______________________________________________________________
Karl:
I am a partial foot amputee (Lisfranc) in Sweden with a long
experience as service consumer and have had this dialogue with
Michael in Germany. If you are involved in these problems and want to
join the discussion, you are welcome to me or
Michael Maier <maier.ortho@t-online.de >
<URL Redacted>
Michael:
I am born in 1964, my profession is orthopedic shoe-technician, which
is an indepentent working area here in Germany (indepentend from the
orthopedic technicians)
I have, together with my father, a workshop here in Karlsruhe, 140 km
south of Frankfurt. Our working areas are all kind of foot ortheses,
orthopaedic shoes, insoles.
Karl:
For the moment I will only mention one question.
I have - as one of the very few in the Scandinavian countries - tried
to use a siliconprostheses for my Lisfrancstump. It was just a
siliconfoot put on my stump without any other applications. It was
not bad but as I since some years have a thight and stiff prostheses
with a supporting splint on the front of the leg, which
is acceptable and never gives soars, I prefer this old one. The
prostheses I thus am used to, takes up a lot of pressure through the
splint.
It has surprised me that in literature and contacts with friends
outside the Nordic countries, it seems as the siliconprosthesis are
very common and also appreciated. How is it in Germany ? Do you have
any experience ?
Michael:
In my opinion silicon feet are too soft. It has the full forces on the
front part of the foot stump. We use normaly a modified type of the
ortheses you wear.
That means, we use also an supporting splint on the leg, but in
different lengths and different stiffness. It depends from the
amputee, if he is very active and, of course, of his weight. The
splint itself is build up in a sandwich technologie, with glas fibre
or thermoplastic material. So we can transfer the load up to the leg
and release the footstump in the front part, without giving an
uncomfortable feeling of pressure to the leg. The forefoot is
made out of soft material, which gives more comfort and makes a
dynamic walking
possible.
We could not reach all this mechanical effects with an simple silikon
foot.
There might be people who find them sufficent, but I prefer the other
kind of ortheses.
Karl:
. Are you speaking about a silicon foot with supporting splint ?
Michael:
No, we are using two types of foot prosthesis. One is made of a
polyethylen foam, with little weight and flexible for very active
persons. Another is made of cork and one layer of flexible rubber,
which gives a feeling of more stability than the foam
foot for the fore foot amputee. Silicon has more weight and is much
more expensive.
Karl:
In Sweden we have tried to find a compromise between a quite stiff
splint, which don´t allow any movement of the ankle joint, and an
insert
without supporting splint and full movement of the joint. Experiments
are going on with some disappointments.
When you mention the stiffness of the supporting splint, I have the
impression that you are able to vary the stiffness, which may give
more or less of ankle movment. If so, don´t you have difficulties
with breaks in the material which is bending for every step ?
Michael:
Yes, that was a big problem. The normal materials like polypropylen or
polyethylen will break very fast. We have tested a special durable
elastic thermoplast, which does not break under load. With this
material we get only a half stiffened ankel joint. It is a
thermoplast which is very flexible and with a melting point around 90
degree celsius, which is much lower than the normal used thermoplasts.
We use it for longer fore foot stumps, up to the Lisfranc
line. For shorter stumps it depends, if the stump can bear the higher
load compared to a normal stiffened ortheses. We use this material
since about 3 years, and up to now we have very good experiences.
These orthesis are much more comfortable than the totaly stiffened.
_______________________________________________________________
Citation
Karl Montan, “Silicone and stiffness,” Digital Resource Foundation for Orthotics and Prosthetics, accessed November 4, 2024, https://library.drfop.org/items/show/210118.
