Hydraulic/ Pneumatic Prosthesis

 I had the idea a while back that instead of using an amputee using a traditional sleeve or an osseointegrated post , one could create a self contained receptacle within the prosthetic that is made  for the residual limb.The receptacle could fill the walls and floor with fluid/air and have it perfectly conform to the changing form of ones residual limb, removing the need to visit a prosthetist as often and or having to replace prosthesis as often as well. is this a plausible area of research? 


  • Look up Hugh herr. watch his stuff. He's done that and lots more. 
  • Sooo... Do i just scrap this idea? i can't find anything about him that has this idea.
  • did you watch his ted talk? he goes into a whole thing about making better prosthetics and mapping the remaining limb to make custom fit parts that don't require any extra connection to hold on really well. He explains it in detail. I'd watch that and if nothing else see if you get some ideas. 
  • I was meaning some sort of 1 size fits all prosthetic. Hugh Herr's ideas and research are still quite expensive and in their beginning stages. My idea was to create a singular prosthetic that is affordable for the average American, Even out of pocket, and that can be applied in a more timely fashion.  Hugh Herr's ideas require extensive mapping of the residual limb and the crafting of a custom socket/prosthetic, Although his are almost definitely higher in quality. What i am trying to go for is Fast, Dependable, Affordable.
  • Almost like the blood pressure machines in cvs/pharmacy type places? They airbag around your arm.
  • Yeah, just needs a bit more fine tuning. I'm thinking several bladders that you can control how they inflate.
  • Also, One could save a Config of how they like it to inflate, Making the process just that much more easy and faster.
  • If anybody has any ideas on it / Want to work on it with me, Say so and i'll give my Email.
  • I would try getting hold of one of the pressure cuffs it might be a good place to start for designing or even repurposing it.
  • once read a paper about robotic gripping. It was named "Universal robotic gripper based on the jamming of granular material". Might not be 100% ontopic but at least somewhat related.
  • edited December 2015
    @ThomasEgi, does this look familiar? I remembered seeing it a few years ago. I am pretty sure that I also saw an almost production ready version, but I can't recall exactly where.
  • Eh, Might be a cool Hand prosthetic.
  • Which could be affixed with my idea!
  • @ChrisBot Yes, that's precisely the thing I ran into in the past!
  • He was talking about using this to attach to the remaining limb, not as something to go on the end of a prosthesis.
  • The operating principle may work for both.  Attaching and gripping.
  • I would feel as if it would get to be painful after a while, don't know why. I think it's probably because it would cause a strain on the residual limb

  • Does anyone know a lot about computing/Machinery? i am more into the Medical/ anatomical aspects, I am learning to be an electrician but i need help doing this. Anyone wanna help?
  • edited January 2016
    I can draw 3D models I can reasonably well work on mechanical systems, plus I have always been mechanically inclined, however my guitar project is eating up most of my time. Please still ask you questions this is a field I am strongly thinking about going into, I would love to learn more about this from a biological perspective.

    John Doe
  • If you need help with something, simply ask for it. There are many great minds on this forum willing to help with specific problems.
  • edited January 2016
    How's it going!

    I'm a below knee amputee.

    For a socket (the thing your leg goes in) to be comfortable, it has to put very specific load bearing pressures on anatomical areas which can tolerate said pressure, while putting less pressure on anatomical areas which cannot tolerate pressure.

    By way of example; the distal end of the medial condyle (of the Tibia) can tolerate a lot of load bearing pressure, whereas the lateral side of the neck of the fibula cannot, because pressure there puts pressure on the fibular nerve which hurts - in my case I have Wallarian degeneration and so can tolerate barely any pressure there.

    Additionally, new amputees often have very sensitive distal ends and can hardly weight-bear distally. In the past I could only tolerate about 10lbs and now (3 years post) can tolorate closer to 60lbs.

    Owing to different residual limb lengths, circumferences, problematic areas, load bearing distribution needs and the like, I can't feasibly think of a way to make a one-size-fits all prosthesis. You're kind of trying to create a one size fits all shoe, with the added difficulty that feet are built to tolerate the full weight of a foot-having person's body, whereas residual limbs are not.

    However, just because I can't think of a feasible way for this type of socket to happen does not mean it can't. This idea could possibly be better suited for upper extremity prosthetic devices, maybe?
  • Do you believe it would be the same result on a limb like the arm where the load bearing weight wouldn't be the same as if you are walking? Obviously I'm not saying enter a weightlifting competition anytime soon.
  • No, while I have fairly little experience with upper extremity prosthetic devices compared to lower extremity, the load bearing weight of a UE prosthesis is nothing compared to a LE prosthesis.

    Also, in both cases, you have to have a way to keep the prosthesis from rotating. That's done by locking it to the bony anatomy (condyles/epicondyles etc)
  • Hmm tricky ok
  • Hello ziztur, i use the term "1 size fits all " very loosely. I was intending on putting a series of bladders that could fill and support the areas that need support and be lax where they are needed. How this is a "1 size fits all" prosthetic is that it could change along with the residual limb, making it more comfortable and possibly reducing the frequency in which you must get a new limb.
  • Also, one should have it custom programmed for your form, I do not recommend just handing someone  the prosthetic and saying "Have at it"
  • It almost sounds like your trying to use memory foam on a prosthetic.
  • @JohnDoe

    Well, If it works it works. But no, i don't think i will be using memory foam, Unless it is just as an added cushion.
  • Given the insights from ziztur I doubt there's a simple one-step solution to the problem. Maybe a combination of all mentioned techniques could provide some usability. Wild fantasies with hexagonal pads of different types on an adjustable framework spin up. Maybe even stacking them. Adjustable framework on the outside, thin layer of foam in the middle, jammed granular pad near the skin for the fine shape.

    I wonder how the transdermal coating experiments would play along with this to create bone-anchors. I'm not aware of directly bone-anchored prosthesis so far (not into this topic so please update me if there are)
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