Thursday, May 26, 2022

transtibial responses

Matthew Mikosz

Matt,
Your technicians are WRONG! Why do they even think they should be explaining any clinical aspects of biomechanics and dynamic alignment with a certified (licensed?) practitioner. Show them the way YOU know it should be done and have them do it that way. I would not put a “finished” prosthesis on any of my patients if they had been aligned and assembled the way your techies are doing it. I suspect they are doing what is easiest for them with little or no regard for the patient who has to walk on, and live with, their prosthesis. Teach them the “DO IT RIGHT THE FIRST TIME” technique and remind them tactfully that they work for you.
Steven Fries, LPO
Fort Myers, FL

I concur. It sounds like your technician is overstepping his base of knowledge. A vertical pylon at mid-stance is the standard for alignment.
Bill Arrowood, CP

Matthew,

I feel the same way that you do. We do two stage laminations at our office
for three reasons. The first is a vertical pylon is more pleasing to the
eye for everyone involved. Second, you have full range of adjustment if
needed after transfer. Third, it makes it easier to ensure the foot is
flat in all planes, especially midstance.

They are correct that after putting the prosthesis in the transfer jig, the
foot and socket are in the same relationship even if the pylon is leaning.
But I’ll tell you that if you are giving them a socket with a slide adapter
on it and they are transferring out the adapter for a standard pylon without
relaminating or gunking the socket onto a block or pyramid, your alignment
will be off. It may not be much, but it will be off.

I know it is more economical and less time consuming but I own my own
practice where every dollar counts, and we incur the extra expense and time.
Vertical pylon at midstance whenever possible. Just like they taught us in
school!

Just my two cents. Good luck with the debate.
Sure your techs. think its ok it is way easier that way to fab.. I
personally can not stand a pylon that is not vertical at mid stance.
for a few reasons:

1. looks bad in front of doctors, p.t’s, and patients.

2. Patient is robbed of possible adjustment range if componets are not
zeroed out during transfer. You may need that extra three degrees when
the alignment needs adjustment or a p.t. wants something changed.

3. cosmetic finishing can be a problem if things get to far out of wack.

4. your visual clue to correct alignment when walking. It is easy to
spot change if you know when you delivered the prosthesis 3 months ago
that the pylon was vertical at mid stance and now its not. if it was
leaning when you del. will you notice a change.

My suggestion is to suggest a one shot lamination method that takes into
account for this problem. They can have there easy one shot and you can
have a quality finished product. I use simple products that do not raise
my cost of production to accomplish this in my office. I fab all my own
sockets and do not like making double laminations either. I do one shots
with the fillaur shuttle lock 3-S original and oww attachment block. you
can also use the coyote lock products to do this but they are high dollar
locks.

joe young cpo
Mathew,
Do you remember the OWW carbon copy III? That was the one with the heat flexible pylon that when aligned looked like a snake wrapped around a tree. No it really doesn’t matter if the pylon is verticle with endo components as long as the foot socket relationship is correct. Butttttt!!!!!!!!, I do like mine as vertical as possible because if there is any modification in alignment after finished, it is easier because all screws are close to neutral.
Karl Entenmann, CPO
Preferred O and P
Federal Way, WA

I agree with you.

Tom Martin, CPO

Matthew-
This debate has been around as long as I have been working in this field (31yrs), and for some time before that.There are of course more considerations than what I write here, but I hope this helps. Early modular alignment jigs (ie, Berkley) made no provision for angular adjustment at the ankle. The vertical pylon was used as a means of referencing the relationship of the foot to the socket and the ground plane. Since the bolt hole of the Sach foot was considered the reference for foot placement in the TKA alignment system, the center of the vertical pylon provided a convenient visual aid. I’m sure you have seen cases where using the slide adapter to achieve optimal socket position has left the connection of the vertical pylon in a position that is both structurally and cosmetically less than desireable.
The advent of more universally adjustable modular systems with independent adjustment at the ankle removed this constraint, but also required rethinking the validity of “vertical pylon referencing”. Functionally, the foot and socket could be connected by a multitude of different geometric configurations (spirals, zig-zag, etc.), as long as they are structurally sound. Yes, as long as the socket and foot position are maintained, the prosthesis should function as aligned at trial fitting. If for you, the visual aid of seeing a vertical pylon during stance phase is important, this is a non-functional constraint that will affect your outcome. You also mention single lamination shuttle locks. Since the proper position for the lock is center and in the length axis, this may also affect placement of the adapter (especially if the adapter and shuttle lock are one unit. The balance here is that the technician should not rely entirely on the adjustments to achieve connection geometry, but should try to allow for future adjustments. I know this may not be the answer you are looking for, but it is based on years of experience, and a debate is about exploring issues.

Respectfully,
Patrick Conroy
Otto Bock Technical Center
14800 28th Av NIf the foot to socket relationship is maintained in the alignment jig then
it does not matter what you put in between. The angled pylon is likely to
be the lighter of the two, but unless you are using a pre angled component,
adjustability will be lost on the initial alignment. another issue would be
cosmesis, as one may finish better than the other.

Hope this answers your question.

Win
Suite 110
Plymouth, MN 55447
800-795-8846Your felt need to see a vertical pylon is old school. Depending on the
endoskeletal components, the relation to socket and foot is what matters
most. As long as the foot is vertical when it needs to be, what connects
the two can be anywhere.

In my opinion,
Dave A. Janke CPOHi Matthew

Your Techs are right that the function of the foot is the same for both set-ups, the fact that the pylon is not vertical is irrelevant, what is relevant is the position of the forces that means that the position of the socket in relationship to the foot is what is important how that is maintained is not very important. however I do prefer when the transfer takes place to have all alignment in the neutral position so that after the prosthesis is completed there is still the full range of adjustment. Hopefully no further alignment changes are necessary however if there are and the alignment screws are at their maximum then this can be a problem. I suggest using a laminating lock with a separate pyramid adapter so that the neutral position can be maintained.

Hope this helps.

Best wishes

Gary Seaman
Prosthetist & Orthotist
Post Grad Dip Clinical Gait Analysis
Prosthetic Consulting
Cologne, Germany
[email protected]
http://hometown.aol.co.uk/opexcellence/1.html
Direct line phone- 763-489-5139

Wood block, vertical pylon at midstance… having a vertical pylon is your “true North” when going back to do any fine tuning, it also decreases angular stresses to the components. Your techs aren’t thinking like a practitioner. Their way will “work”, but it’s not the “right way” to do it.

hello,
I would agree with you on liking a vertical pylon, it is more pleasing
cosmetically if no cover is used and it is more pleasing to the old
prothetic eye we’re all suppose to have. The techs are right if all
things were done right with the jig the socket foot relationship has not
changed but it makes it a lot harder to see a deviation if there is one.
My suggestion for a happy medium is if a single lamination shuttle is
used, an offset pyramid or double offset pyramid can be used to
establish vertical pylon or a slide unit from PDI or Bulldog can be used
if the angle is severe enough. The slide units mean more money and a
little more weight sometimes but the pylon is vertical which can cut
down on pt comments like “Is that rod suppose to be bent like that?”
Anyway just a few suggestions hope they help.
Kevin Gardner, CP

Lisa Urso, CPOThe relationship between the socket amd the foot are the same in your
circuntances. The fact that the pylon is leaning and its not vertical at mid
stance,will only matter, if you have a heavy patient and dont want to take
any chances with pylon failure. As the pylon is stronger vertical. I dont
use the four prong vertical pyramid adaptor because I also dont like my
pylon leaning in any direction since the alignment still the same but the
vertical floor reaction force will change the gait pattern. I always use a
vertical pylon with all my alignment screws at neutral when I am finishing
a BK.

Albuquerque O & P

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