Summary of responses: Socket Modifications for Lanyard Ssytems

Summary of responses: Socket Modifications for Lanyard Ssytems

William Lifford

9/24/2003

Hello everyone,

Once again, thank you for your responses to my post, Socket Modifications for Lanyard Systems. Just in case some of you don't remember the questions I posed, I have included a copy of my original post here.

My post read as follows:

Our facility recently started using the OWW Alpha Locking Lanyard for some difficult patients that weren't having great results with AK suction sockets for various reasons (weight fluctuations, improper donning, etc.), but we have noticed that upon unweighting the prosthesis going into swing phase, the residual limb often distends due to the distal attachment point. I imagine the same thing would happen quite a bit with AK pin suspension systems; however I haven't done too many of those and am not tremendously familiar with them.

My question is: For those of who who have used this system before, what is the best method for accomodating this distension? Do you cast the patient while standing with a weight attached to the distal umbrella of the liner? Or do you lengthen the cast by a certain amount after the fact? It seems like pre-distension of the patient's limb while casting would be the only way to have the socket fit in such a way that the distal umbrella would reach the bottom of the socket while preventing any loss of suspension due to tissue distension.

Any thoughts on this would be greatly appreciated!

Bill Lifford, C.P.



The Responses were:


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  If you're casting on your own, the easiest way is to have the patient stand and attach a lanyard to the liner via the distal screw, then tie the lanyard to the bottom of your casting stool or any other handy object! Tie it with the appropriate amount of tension - I find its different with different liners, and the generally does the trick. I was originally taught this to use with BK clutch locks to allow for the inevitable distorting with donning, but it works OK with the lanyard systems too.

  Vicky Jarvis CPO



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It seems like pre-distension of the patient's limb while casting would be the only way to have the
socket fit in such a way that the distal umbrella would reach the bottom of the socket while preventing any loss of suspension due
to tissue distension.

(Please note that this response is actually a direct quote from my original post, so I can only surmise that I am a true genius and that I already know the answers to my own questions! :) -- Bill)

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You ask a very interesting question, and I would be most interested in
viewing your results. I hope you will share them with the list.

Charles H. Pritham, CPO, FAAOP
<Email Address Redacted>


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You have an interesting problem, I would not recommend casting with a weight attached to the distal end of the prosthesis this is because when donning the prosthesis the shorter wider residual limb normally forms a plug and then the liner needs to be pulled into the socket this can cause problems on the distal end of the residual limb. The socket should also not be too large around the distal third. When I take measurements I take the distal third without tension and do not reduce this at all. I also tend to use a slightly narrow ML and this helps a little to contain the soft tissue without too much pressure circumferentially. To lengthen the socket is a good idea but only enough that there is still total contact on weight bearing. Depending on the liner used elongation can be limited the Iceross Transfemoral liner I have found to be the best in these circumstances as the liner does not elongate. Another useful idea is to use Velcro around the proximal edge of the socket on the outside about 1 inch distal to the proximal edge and reflect the liner over the socket and it will stick to the Velcro. The best Velcro is one available from Camp it is very low profile and comes self adhesive and different sizes can be cut and placed around the socket. this method reduces some of the distal pull from either the lanyard or the pin and works very well. The only negative effect is that the liner after a while starts to get fluffy but still works. I have done many Transfemoral sockets with liners and there is always a compromise this system however I have found to work well, please feel free to contact me if I can be of any further help.

Gary Seaman
Prosthetic Consulting
Cologne, Germany
<Email Address Redacted>
<URL Redacted>

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The problem, at least in my opinion, is the Alpha liner. They do not have the same reinforcement distally to prevent the milking that occurs during swing phase. I have quit using the Alphas and have turned to the First Classs Liner from EuroInternational, the Ossur Comfort Plus (I try not to use Ossur products because of their OAF Extortion Program) or the Bock 6Y70. All are great and seem to have eliminated the problem you have referred to. Hope this helps.
Steven Fries, LPO

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end of responses