Lower Limb Amputee

[HobbesChoice]

Hi there!
My Dad recently lost his lower leg just below the knee due to having diabetes and breaking his ankle in a fall He now has a brand new prosthesis though and is anxious to get back on the bike. His physio and prostheic fitter have both told him to fit a smaller pedal crank to his bike as the prosthesis prevents his leg coming all the way up (it digs too far into the back of his knee).
I've googled various terms for amputee pedals and cranks etc but the only thing I can find is they say to attach the false foot to the pedal in some way (ie. velcro, toe clips etc). Nothing about changing the pedal crank. But he really can't raise his knee high enough for the upward pedalling action, so would any of you know anything about this by any chance please?
Many thanks!

 

[PK99]

Not the answer you are looking for, but there is a guy who cycles in Richmond park regularly (at a good pace!) who has a lower leg stainless steel prosthesis - may be an alternative falsie is the route?

 

[Bigtwin]

Not specificially, but. Which side are we talking? If non-drive, just fit a shorter crank.

If drive side, then a flattish crank arm should be capable of being shortened by drilling a new hole and tapping the thread - any engineering shop will do that no problem if you don't fancy it yourself. So you may need to buy a new spider depending on what shape he currently has.

See here too: http://mnhpva.org/Meetings/July_02/Short.html

http://bikesmithdesign.com/Short_Cranks/m440.html

and: http://www.bentrideronline.com/messageboard/showthread.php?p=422149

 

[ACS]

Again not a direct answer but I met up with a rider over the weekend who had stainless steel prosthesis (drive side). By his turn of speed on the hills his set up certainly worked for him.

Try this link

 

[Chrisz]

Not a clue but you could try getting in touch with Hadley Court - I know there are several guys there who have similar problems (I've cycled with them) and someone may be able to provide some advice.

 

[HobbesChoice]

You've all been really helpful. Thank you so much.

Bigtwin - he was told that the short crank was the way to go but I couldn't find any information so thank you for the links.

I think I'll also contact Hadley Court - thanks Chrisz because this is completely new to him so any advice would be very well received.


He has his prothesis on his non-drive size by the way.

 

[Will1985]

Alex Simmons is the person to talk to about this - he's on TTF and BR. He's an Australian cyclist and coach who uses a lower leg prosthesis following a freak cycling accident a few years ago. His blog might be helpful - it is for power training!.

Btw, it's DMRC Headley Court, not Hadley.

 

[Paul_iow]

Can your dad raise his sadle at all? By having it higher his leg would bend at a lesser angle so the prosthesis would not dig in as much.

Also is there any possibility of your dad having another limb made with a clipless pedal attachment (cleat? not sure what the right bit is) in it? This could then be clipped into the pedal as "normal".

 

[palinurus]

I've seen a crank arrangement designed for riders with limited leg movement recently. Can't find the particular site where I saw it but I did find these (which are similar)

MTB Mods for Leg Amputees

Hinged Crankarm

http://www.oandp.org/jpo/library/2005_01_035.asp

 

[MichaelM]

Headley

 

[HobbesChoice]

Hi Paul iow - Thanks for the idea, but if he raises his saddle for his bad leg then the good leg will be a bit out of synch for pedalling. We can get a cleat shoe for his false foot, that's not much of a problem and we'll be doing this once he's got the balance right on the bike, but to start with he needs to feel he can get his false foot off quickly and easily. I think we'll just do a velcro patch up to keep the foot stable on the pedal initially as it won't take him long to gain enough confidence I shouldn't think.

Those links are helpful, thanks Paulinurus.

 

[HobbesChoice]

Headley

Thank you MichaelM. I'll contact them.

 

[peanut]

sounds to me like the prothesis needs to be adapted for cycling. post operative exercise is very important and if the prothesis prevents cycling it cannot have been made with exercise in mind.

I have to say though I wouldn't have thought that the thigh would come anywhere near horizontal if the saddle is set up correctly.

I would suggest your Dad asks to be referred to a Physio specialist . Can't believe this problem hasn't been solved before

 

[HobbesChoice]

Thanks Peanut. My Dad sees a physio twice a week and apparently it's normal for a lower limb prosthesis to have cycle issues as the NHS have provided a "standard" lower limb which, although can be used for cycling it's primarily focus is on walking and will need some adjustments on the bike too. I've spoken to quite a few sources now and most aren't surprised that a short crank needs to be fitted to the bike to allow for the minimised movement.

I believe he also has to have a few adjustments made on the prosthesis over a period of time to ensure it's a perfect fit for him which is quite normal and I do think one of the adjustments will be because it touches/rubs the back of the knee just on walking!

You've noted on your weight loss list that you'll have to cut something off after your last weigh in? - just the lower leg itself is about half a stone if that helps???

 

[peanut]

Thanks Peanut. My Dad sees a physio twice a week and apparently it's normal for a lower limb prosthesis to have cycle issues as the NHS have provided a "standard" lower limb which, although can be used for cycling it's primarily focus is on walking and will need some adjustments on the bike too. I've spoken to quite a few sources now and most aren't surprised that a short crank needs to be fitted to the bike to allow for the minimised movement.

I believe he also has to have a few adjustments made on the prosthesis over a period of time to ensure it's a perfect fit for him which is quite normal and I do think one of the adjustments will be because it touches/rubs the back of the knee just on walking!

You've noted on your weight loss list that you'll have to cut something off after your last weigh in? - just the lower leg itself is about half a stone if that helps??? B)

sounds like the prosthesis is going to require some surgery I can see the problem. If you make the prosthesis suitable for walking and carrying weight it won't be suitable for cycling and visa versa.
Sounds like it really needs a different attachment or adjustment that will allow a fuller movement of the joint.

I think putting a smaller crank on is a real poor option to be avoided if possible. Your Dad is going to be lop sided in the pedalling motion and forever stuck with only one bike he can use.

Far better if possible to use a standard set of cranks and change the pedals. Then your Dad can simply transfer the pedals to use any bike he wants to.

By the way you cannot drill and thread cranks there isn't enough metal on the arm of any crank and it would fail. It would need to be specially made