Flexible sockets

Flexible sockets

Stephan Manucharian

9/27/2013

I apologize for the delay in re-posting.
My original question:

Dear List,

I would like to find out what is your preferred material for flexible inner
sockets for transfemoral prostheses with locking gel liner suspension
(pins, not KISS). I always preferred Proflex-with-silicone and still use it
for all full suction as well as KISS type suspensions, however, it does not
always work well with shuttle locks. Cylindrical or almost cylindrical
shapes of the residual limbs are among the types that don't like Proflex.
In my opinion, Proflex has higher coefficient of friction as compared to
Durrplex/Vivak used for check sockets, so when you transfer a successfully
fitted check socket into Proflex material, the limb does not slide in as
easily and the fit changes drastically. For these types of limbs I
successfully use low density polyethylene, as it is almost as smooth as
Durrplex, however it does not have the elastic qualities of Proflex. So,
what is your preferred material for such residual limbs?



Responses:

Yep, I was most frustrated by this as well. Thought for a while material
shrinkage or something techs were doing. Then I found the secret...
Use a little corn starch on the proflex w/sil for 2-4wks. Donning issue is
eliminated. Seems it takes some time for the material to lose it's
tackiness. Once pt can don w/o issue they can start NL cleaning of socket.

Bock Thermolyn Soft

Use proflex with silicone but provide the patient with Stoner Silicone
spray and have them spray the socket ever night don't wipe it off. This
will allow the residuum to slide into the socket with ease!

Stephan, I have not seen the friction problems with proflex/silicone.
Friction is the reason I switched from plain proflex (or equivalent.) I'm
very interested in the responses.

I asked the same question several months back. I had used seaflex for many
years but started having fit problems going from check socket to finish. I
gave switched over to orfit on others rec's and have made over a dozen
sockets in the past few months.

Have found relatively constant transition from check socket to finished
socket. Side note, I personally don't like proflex with or without
silicone as neither gives a uniform pull. Orfit has been pretty easy to
work with. It's available through cascade.

Well put. I have had similar troubles with this material and have always
returned to LDPE or MDPE. I have not found a suitable flexible material
despite looking. I would like to try opflex by o&penterprises however have
not been able to....yet. I am curious to see what your inquiry returns.
would you please share it with us? Thank you for your time.

I totally agree with your point as I also have been finding out recently.
we use to bubble mold thremalynn stiff material from Otto Bock but I felt
that it was to stiff and went to Proflex-with-silicone but been have
friction problem. I have stop using it on BK's and would hope you get some
good responses. Please forward them to me.

I cut the flexible inner liner proximal to the lock. I usually terminate
the flexible inner liner a couple of inches distal to where the posterior
cut out ends. It allows the lock body to be securely bonded into the
socket, reduces bulk, and reduces weight. I also powder the inner surface
of the flexible material for the liner just before vacuum forming, thus
reducing the tackiness/COF.

I have used Proflex with silicone AND also the proflex w/o silicone. The
one without silicone is a smoother and less tacky material closer to the
LDPE that you mentioned.

When doing a locking liner, I always laminate the locking mechanism into
the carbon frame, and cut a hole in the bottom of the inner socket in
these cases. I almost always use the Cascade IRS 650 lock, and it has the
ability to actually turn the button and pull the limb down into
the socket. The hole I cut is about a 2 diameter hole, which is done in a
way that does not change the shape or fit of the finished prosthesis. I
put the dummy piece onto the plaster model, and then pull the inner
plastic. Then I cut the plastic so that the dummy is fully exposed, which
is the 2 hole that I mentioned. Then I pull the PVA bag over the plastic
inner socket, and tape it off and seal it around the dummy/lamination
piece, and proceed from that point. It does end up making a nice design,
and then the actual prosthetic leg is attached by the locking device.
 I have seen too many legs made where the lock is actually in the inner
socket, and then the only thing holding the inner socket to the outer
frame is some double sided, cheap tape. That is the ONLY thing that
keeps the knee and foot connected to the patient. The inner socket is
attached by an expensive locking device...but that is only a piece of
plastic that covers the residual limb. THEN the rest of the leg is only
connect to that plastic inner socket by some cheap carpet tape or similar.
That doesn't make any sense to me at all. The locking device should hold
the entire limb onto the patient...and not just the plastic inner socket.
 That's how I do it here anyway.....it seems to work fine.


We use extra soft thermolyn, it works great, it's still not as slick as
durrplex but it is very close.

In case you haven't heard this already, we have Orfitrans Extra Soft. It is
like Proflex but without the tackiness. There are various thicknesses, with
and without silicone.

 THANK YOU ALL WHO RESPONDED.

--
*Stephan R. Manucharian, DHSc(c), CP, BOCO, LP(NJ), FAAOP
Clinical Director
Orthopedic Arts Laboratory, Inc.
141 Atlantic Ave., Brooklyn, NY 11201
718-858-2400; Fax: 718-858-9258;
<URL Redacted>

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