Responses to Summit Lock

Responses to Summit Lock

Joel Kempfer C.P.

All~

Thanks to all those who responded to my query about using the Summit Lock on
TF.

Here are the responses...

I like the concept, but I do not use the clasp mechanism.  It's a bit bulky
and tears clothing.  Substitute a reinforced velcro strap instead.  Rotation
and suspension excellent!

We have used it several times.  It definitely eliminates rotation.  The
patients that have use it like it and don't seem to have any problems
donning. 
The instructions that come with it are good.  We place a piece of durplex in
the liner when applying the adhesive to the locking mechanism.  Be careful
when
riveting the lock to the socket, if set too firmly it can crack the plate.

I've used it on some long TF sockets and also with a women who had a
significant amount of redundant tissue which made donning the liner the same
way each time problematic.  It has also eliminated rotation on a man I
couldn't get the rotation to stop.  However, I have not started to use it
routinely.  Why?  Not sure.

The Coyote Lock is an awesome piece of componentry! I have used it on
about 5 different patients, all AK's. With great success. You need to
get a good tight partial suction fit in check socket. Then drill out
small hole 1 1/2x 2 Anterior a little higher than ishium level. Then
make mark on the liner thru hole in check socket. Then attatch your
summit lock to outside fabric of liner QUICKLY! You have 30 sec.  To get
a good bond. Make sure you build up with a dummy or something on your
definitve socket mold, so you can see where your hole was in check
socket. Laminate, drill out hole and mount latch to outside of socket ,
donn liner keep it lined up with hole, feed strap thru hole into latch
mechanism.

This is a superior way of suspension, especially for older geriatric
folks. In the pasty trying to donn a suction socket, or find the hole
with the pin etc. was hard. This is much easier. It does help with
rotation also.

I have used Alpa Cushion and Ossur Transfemoral. I like the Ossur, it
allows for less elongation than the Alpha. I have had some breakdown of
the fabric. But it is happening on the edges and over ishium. Not where
the lock is glued on.

Give it a try, I think you will like it!

I started to use the Summit lock six months ago. Use has been only with long
T/F. Have used Ossur T/F liners and Dermo liners.
I consider the lock a big success as a locking insert can be used and you
still end up with the joint center in the correct position. Suspension is
good and as long as socket is tight enough the liner stays in place.
Rotational problems are less evident with the summit than with standard
sockets.

Patient has to be willing to take the time to get the liner on right.Several
tries are not uncommon until they get used to it.
The mechanism is bulky on the out side of the socket.
Attaching the lock to the liner has not been a problem and so far they stay
on and do not affect the liner itself.
For the long T/F it has solved a lot of problems for us and would encourage
you to give it a try.

  The suspension on a prosthesis is meant to counteract the inertia of the
leg during swing phase.  This means that it is in relationship to the weight
of the prosthesis as well as the square of the velocity.  As speed
increases, the stress increases exponentially.
  In our experiences with active patients, the lock you are asking about has
failed.  The attachment to the prosthesis or liner fails.
  Something you can try doing.  I assume you are using a gel liner, flexible
inner socket, and rigid frame.  Modify the cast the way you normally would
do, except leave off the pin lamination dummy.  Instead, at the distal
center (where pin is) place a normal thin, small valve lamination dummy. 
Pull your plastic.  A stiffer inner plastic works better...we us Theromlyn
soft.  Then, use two layers of perlon over this plastic as a spacer.  Pull
your PVA bags and laminate normally.
  Once cut off, trimmed and smoothed, you will be adding velcro.  At the
plastic where the valve dummy was, sand this out to a hole.  On the medial
and lateral sides of your plastic socket, attach sticky velcro, 2 inches
wide.  On the greater trochanter area of the plastic, but about an inch or
so above the rigid frame, rivit on to the plastic two D rings attached with
Dacron.
  On the lateral side of the rigid frame, attach a self-closing velcro strap
that is rivited to the frame and attaches to the D ring attachment made
above.
  To attach the flexible plastic frame to the gel liner, make two straps
lined with Dacron and having the opposite velcro that was attached to the
inner plastic frame.  In the center of this, melt a small hole and put a
10mm nylon bolt through this into the liner.  You can also use a metal
thread reducer (SPS sells these) if you cannot find the nylon bolts.

To donn:  Put the liner on normally.  Then slide the plastic inner frame on
and put the velcro straps through the hole at the end.  Attach the velcro to
the sides of the plastic firmly pulling the residual limb into the socket. 
Then slide the plastic socket with residual limb inside into the rigid
frame.  Sinch up the lateral velcro strap through the D-rings on the side.

  You should be good to go then.