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Juan Foote 02-10-13 08:06 AM

New foot
I just had a new leg completed and have been wanting to try a different foot. My last one was really good IMO (and I can't for the life of me think of what it is) as far as walking and performance. The major letdown is that ONE month out of warranty the foot is delaminating. Apparently I am not alone in the CF foot world, it is a common complaint.
After having tried a couple of different feet and not being particularly satisfied as compared to the current, and unwilling to go to them again after the failure, I have been given one of these new "Rush" feet. I have to say that I find it a bit worthy of concern being the first person within this company to use one, and no wonder as it appears the foot has only been on the market for a couple of months now.

I decided to try and read up on the foot a little. Its made by a company called Ability Dynamics. They claim that this new fiber composite they have from the airline industry acts and feels better than CF and will not fail as soon. (I noted that they didn't offer any longer a warranty) They have this "nifty" trademarked name and claim that it's been around and been in use for years, blah blah. Well, I am not Google-fu master, but aside from the manufacturer website, I see nothing, no-where that isn't a paid advertisement or review of the product making the same fabulous and vague claims with links back to some mystery users of the product...also glaring and spewing shills as far as I can tell. Now, I don't want to just run these folks down. It isn't my intent to call them out without further use of the foot, to be fair I have had it a week. Just call me a skeptic though. Usually where I see a lot of smoke I figure there is some fire. Here is some newcomer to the O&P world making fantabulous claims about some foot made of miracles and answering all our prayers, right?

Now, perhaps I am just in on the "ground floor" and am of the lucky few that get first dibs at what will be a renaissance in prosthetic foot technology....or maybe I am just a guinea pig for some new, untested fad....not like that has ever happened in the world of prothetics.
The foot is very dynamic. Read as mushy as hell. Is that a bad thing? Perhaps not always. My stiffest carbon foot is wonderful for activity, but rough as heck on my knee and really hard to walk in the yard in. The last foot, by far the best walking foot I have had so far, failed really fast and left me unwilling to spend another $4K on their product. It did work quite well with my knee and had a great range of motion. This foot mimics and even surpasses that by a long shot. It is almost scary watching this foot smash down under weight. It moves and pivots in every direction quite easily. I did note a rather irritating "grab" at the end of the stride on toe off, rather weird feedback from the return action of the spring. I am sure some further adjustment will help that and I am anxious to see if the increased spring causes any hip or back issues. There is no doubt that with this effective leg length difference it will show up somewhere. I will be trying a higher category of this same brand, just for comparison.

Anyone else out there using this foot, or familiar with some information on the composite?

esther-L 02-24-13 02:29 PM

I've been using some model of Otto Bock Advantage DP foot for about 9 years. It was first the Springlite Advantage foot, and Springlite was bought. This is at least my 5th foot with carbon fiber in it. I have never had a delamination problem. The urethane sandwich between the 2 layers of CF has been a good feature for me.

This Rush foot has a pretty bamboo color. There is a lot of marketing fluff in prosthetics components.

There is a prosthetist story about delamination of an early flex foot that involves weight lifting. Are you doing weightlifting at a gym or carrying things that weigh more than 50 lbs? If you do that regularly, your prosthetist needs to account for that.

You can see from reading about carbon fiber bike frames that there are different manufacturing techniques for carbon fiber. I don't know if they all start from the same raw material sheets of CF or not. There do seem to be different choices for the epoxy/adhesive component. There is lots of marketing fluff thrown around about carbon fiber in bike frames.

Here is a company with a bunch of trademarked names for aircraft CF materials There is no way to tell whether the Rush foot is using their CF materials, or those from another manufacturer. Someone from the management team is from Boeing, so they may licensed some Boeing intellectual property.

Juan Foote 02-26-13 08:51 PM

The previous CF foot, and my first halfway decent one (Renegade) was an awesome foot and is still doing quite well for me as a cycling foot. The biggest issue that I had with it is how stiff it is. Awesome for sprinting, jogging, and even walking on smooth surfaces but it about breaks my knee when I walk on any uneven surface. It was selected as a result of my activity level, size, and the fact that I do have to carry heavy items from time to time, not that I like it or that it feels good just something that has to be done sometimes.

After a while that foot caused me pretty severe pain in my knee so we decided to go with a foot with a bit more motion. I cannot for the life of me recall what the name of my current foot is but it walks like a dream and was wonderful for my knee. The Rush foot was selected to mimic that action but with a much higher weight rating. I still don't know if I care to be the guy on the ground floor of an unknown foot.

Complicating matters, my prosthesist went missing on a Lake a couple of weeks back and is presumed dead. Not only is it tragic on a personal level as we were quite friendly and had a good rapport, now I have to start over with a new "doc" from scratch in the middle of a new leg build while testing product.

benajah 03-01-13 12:33 AM

When I was in the army hospital, they basically gave us free range. Let us choose our suspension system, and more or less let us try out feet free range. We just shopped the Internet and they ordered it for us. Nearly without fail, almost all soldiers ended up settled on one of three feet....Freedom Innovations Renegade, Ossur Mod 3, or a Reflex VSP.
Granted, these are all very active young men planning on going back to active lives and construction or factory jobs, but there is something to be said for figuring out what's wrong with the knee, fixing it, and moving on. If you can't fix the knee, then there is a good chance you need different feet for riding versus walking, because the feet on the market that are good for riding, are too stiff for walking with knee problems.
no easy ground, there's just always a compromise, just as with any mechanical product on the market. Unfortunately this particular product happens to be a pseudo part of our bodies.
The best foot I have found for riding is that crazy stiff foot they taught me to walk on...the one that doesn't flex at all, heel or toe. I saved it and now use it or a peg leg on my riding leg.
I do not ride a bicycle and walk on the same foot. The best bike riding foot on the market is also the cheapest and most basic, or just go and make a peg leg for like 200 bucks.

Juan Foote 03-01-13 07:16 AM

My knee was damaged in the accident where I lost my foot. It is re-set at a 15* angle forward and inside. Basically, I am walking around on the innermost part of my knee joint and meniscus. It was supposed to be "rebuilt" but a bone infection caused it to be delayed too long and it set this way. It needs corrective surgery but my ortho suggested that I just use it till it blows completely out. His opinion is that once you operate on a knee it is rarely as good as it ever was before, even when it's bad.
I have found that cycling has done wonders for my bad knee, so long as I ride on a very regular basis. When I stop for a few days it gets sore as hell and is hard to get started again.

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