Saturday, December 3, 2022

Flexible sockets (responses)

Stephan Manucharian

Original post:

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?

Thank you all, who responded:

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.
Take care,

*Bock Thermolyn Soft*
Greg Straub, CPO

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. Please re-post.
John Brinkmann, CPO

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.

C Jones

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.
Angelo Russello CP

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.

James O. Young Jr., LP, CP, FAAOP

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.

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.


*Stephan R. Manucharian, M.A., MSc, CP, BOCO, LP(NJ)
Clinical Director
Orthopedic Arts Laboratory, Inc.
141 Atlantic Ave., Brooklyn, NY 11201
718-858-2400; Fax: 718-858-9258;

Non est vivere sed valere vita est!

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