Responses:Bicycle Adaptation For Trans-Tibial

Responses:Bicycle Adaptation For Trans-Tibial

Joel Kempfer C.P.

7/1/2013

Dear List,
 
Thank you all for the multitude of timely responses to my inquiry! Here
are the various solutions digested...
 
 In my experience the toe out angle has to be reduced to suit the bike,
compromising toe out for walking. Toe clips and straps are obviously the best
option but an alternative may be using a BMX style pedal which has small
spikes to help grip the sole of the shoe. Good luck.

As a very active AK amputee who fields many questions with regard to
amputee
cycling, I am sorry to say I have no suggestions if your client cannot clip
in or use straps.
Would you be able to post the replies please.

If you have the room use ottobock safety knee

There is a brand of pedal called Crank Brothers that makes a large
platform pedal with a cleat attachment in the middle - their cleat system has a
huge range of float or effective toe in/toe out and can be dialed waaaay
low for easy release. Might be worth a look. Would look goofy on a road bike,
but better then not keeping your foot on the pedal. Not sure if he wants a
platform, but I think it is kind of nice to have something to stand on when
 you're not fully clicked in. Here's a linky...
<URL Redacted>
 
I personally use toe clips and just leave my prosthetic side loose for
easy in and out.
Using a shoe with little tread like a converse Allstar also helps for easy
out if need be.
I know several other amputees that use clipless. Does he have the option
to setup a leg just for riding? A foot slightly toed in helps as not to hit
the arm of the petals.
 
Try adding Velcro pile to the base of a New England Overshoes (NEOS),
which would then be worn over the shoe of the prosthesis, and add Velcro hook
to the pedel, would be something to consider.
 
Try adding Velcro pile to the base of a New England Overshoes (NEOS),
which would then be worn over the shoe of the prosthesis, and add Velcro hook
to the pedel, would be something to consider.
 
 worked with an bk w similar fear. We constructed a clip that attached
to the pedal. It attached medially on the pedal and projected over the
dorsum of his foot only. This allowed him to keep foot on pedal and use the
upstroke and slide out laterally. Extend along medial foot border to keep
crank arm from hitting at heel if needed. Used Kydex first, then aluminum, he
can bend that himself as needed. Worked.
 
I have done two things for patients like this, and in both cases you
pretty much need a dedicated shoe for this, but an avid cycler usually will.
Short TT patients usually have to be managed like TF patients due to their
general inability to internally rotate to step out of clipless pedals. The
fear of being trapped is real, although the problem usually comes when you
are coming to a stop and cannot disengage, which typically means a
relatively painless fall, but who needs the risk. Either approach gives you
complete flexibility with toe out, but depending on how avid he will be with his
involved leg, these may not have enough engagement (i.e. force required to
break contact may be too low). A solution can almost always be had for
recreational riders, but the stronger ones can be a challenge trying to find
enough engagement without creating a safety issue.
One approach is to use adhesive velcro on top of a platform pedal and on
the bottom of the shoe. This is simple, inexpensive, and easily replaced
without tools by almost anyone, almost anywhere, but you can't do much
walking on the shoe without trashing the Velcro, it wears fairly quickly, and the
amount of engagement is limited. The Velcro is firmly adhered almost
immediately with use, but if is he planning to use his involved leg strongly,
engagement may be an issue.
The other approach is a bit more trouble, although not very expensive, and
that is to use a magnet, usually on the pedal, and a steel plate on the
shoe. You may have to spend a bit of time experimenting to find a magnet
that is strong enough without being too strong. After some experimenting I
found that it was usually best to use a relatively narrow rectangle aligned
more-or-less front-to-back, in line with his normal toe out, so that the
magnet could be easily disengaged by abducting the leg, and the long axis of
the magnet would have more leverage to better resist disengagement on the
upstroke. Ceramic magnets are inexpensive, durable as magnets,
non-corrosive, and easily shaped, but have been too brittle for aggressive riders. I
have thought about making a laminated carbon fiber base to help with this
problem, but have never done so. Metal magnets solve the brittleness problem,
but you also get corrosion, enough of which will diminish the magnetic
effect, although it takes a good bit. Disadvantages of magnets are more
trouble to set up, including finding a pedal suitable to mount the magnet on,
and if you forget about your shoe, you can tear up a floor pretty nicely with
the metal plate, much as you can with cleats. Advantages are long life,
predictable engagement, and easy mounting to a standard cycling shoe that is
made for cleats, which he likely prefers if he is an avid cyclist.

As an amputee (bi-lat AKA/BKA) and avid mountain biker, I have found for
my BK side the Crank Brothers eggbeater pedals worked the best for me:
<URL Redacted>

It is the clipless type-meaning the cleat that is included with the
pedals is attached to his shoe, and that is what engages the pedal. What is
great about these eggbeater pedals is that they are 4-sided, so it is a lot
easier to engage than any of the two-sided type pedals I had ever tried.
Also, depending on what cycling shoe he is using, there is usually a
considerable amount of adjustment area so that the cleat could be positioned as far
internally as possible so as to compensate for the 7 deg toe-out alignment.

If that still does not provide enough clearance to prevent his foot from
contacting the crank, you could either modify the shoe to position the cleat
even farther medially, or instruct your patient on how to make the
internal rotation alignment change to his prosthesis when he wants to ride (of
course-that would depend on if he has the type of components that would make
it easy to facilitate this).

For my AK prosthesis especially, I always need an almost straight
alignment of the foot, as well as a swing-only type knee that was very efficient
for cycling, but not at all optimal in terms of gait dynamics. On that leg I
have found it extremely useful to use the Ferrier coupler, so I am able to
quickly and easily switch out of my everyday component to my cycling setup,
without having to go through the hassle of taking off the socket.

Perhaps if the temporary alignment changes for your patient are not
warranted, the Ferrier coupler could be an option. While it does add weight, it
certainly makes my life much easier so I can quickly change components for
various activities.


They make a magnetic pedal for cyclist. I have several amputees that use
them. The magnet is in the cycle shoe and pedal.

 


 
They make a magnetic pedal for cyclist. I have several amputees that use
them. The magnet is in the cycle shoe and pedal.
 
There used to be a couple of types of magnetic pedals that helped keep the
foot in contact. Kurt Yaeger, BMX rider/actor with a TT amputation, was
sponsored by Proton Locks and used them in competition. However, a quick
google search shows they are out of business. Perhaps you could develop your
own set by modifying some old ones?


I wear the biking shoes that clip in. The bike shop can set it up to
detach really easy. It makes pedaling easier because you get help on the
upstroke. Their is an inherent risk of falling and crashing how ever you chose to
ride.
 
Try Speedplay pedals. They have more 'float' than many others and should
accommodate his toe out position, have dual sided pedals that are easy to
get in and out of. You can also find shoes that allow the cleat to be
recessed into the sole of the shoe to make walking easier. Most bike shops will
let him take his bike in and try different pedals and clips with his bike
up on a trainer so he's stable.
 
 I solved the problem by adapting the the tube clamp adaptor so that the
patient can adjust the toe in/out. He got pedal cages which are safer to get
out of. I extended the tube clamp bolt to come to the surface of the
cosmetic cover....obviously not an issue without a cover....and put two stops on
the pylon with a cleat so that he could only adjust the toe in/out to the
stops......works well.
 


 
Joel J. Kempfer CP FAAOP
President,
Kempfer Prosthetics Orthotics Inc.
4365 West Loomis Road
Greenfield, WI 53220
414-817-1452
<Email Address Redacted>