Stump after wearing myoelectric “bionic” prosthesis for 10 hours [graphic #voightkampff]

Any self respecting medical doctor, orthopedic surgeon, prosthetist, and “bionic” researcher will ask you – in a concerned professional way – “and, do you wear your prosthetic arm often, hopefully even daily?”.

We also must accept that wearing “bionic” arms is nowadays assumed to constitute “human enhancement”. This obviously is something I will directly and confrontatively label as bitter, ignorant, harsh and degrading cynicism.

If I do wear my prosthetic arm daily, in their view, that makes me a better human or even more human at the same time as I am, in their view, maybe not so much a better human but a “good doggy”. Really and in fact, we have a reality split in that – at the same time and at once – my realities are two fold and split:

(1) Outside: On one hand, me trying to wear a prosthetic “super” hand – such as a “bionic” hand – makes my shape outline appear more like the shape outline of other people and so there is this aspect of possibly becoming a better, a deeper human. Conversely, the disfigurement of an arm stump thus makes me less of a human – and that is also what the face of many shee shee froo froo people, many so-called superficial people, will tell me when (or if) I look at them. Clearly, my amputated arm can make other people feel that I am less human. And it clearly does so on any given occasion. This is to a very small part remedied by me wearing this “bionic” apparatus – a machine for symbolism and “hope” far more than a machine for grasping, working, getting stuff done or feeling well.

(2) Inside: On the other hand, wearing a myoelectric arm is a really uncomfortable and skin damaging ordeal that is cumbersome and even in the best of all worlds painful. It feels bad to a degree, where I cannot possibly be totally human any more – as I have to push all normal human reactions such as pain, self respect, worry about the skin on my stump, fear of what all that pain does to me, etc. aside. There is a truly heartfelt authentic element in praising my stubborn wearing of a myoelectric “bionic” arm using the words “good doggy”.

So, wearing a “bionic” myoelectric arm on the outside is an act of extreme humane-ness, it approximates the un-disfigured appearance like nothing else. As long as it does not approximate anything, it represents an 80’000 USD promise – and that is extreme in terms of symbolism.

At the very same time, what goes on inside the socket is beyond comprehension to many people – as it is not just not human, but worse, it has truly inhuman aspects. It lowers one, soul wise and as an individuum, in my view.

Here is how my stump looks like after a duration of 10 hours of wearing my iLimb Ultra Revolution at the office, typing and carrying light weight files, possibly holding a cup while rinsing it with water, photographed 1/2 and 7 hours after removing the prosthetic arm. To get the battery to last that long, I had switched the hand off for extended periods of time. Like, when I was typing. Never did my arm look like that after even hard work with the body powered arm such as jobs like hedge cutting [link], scrubbing [link] serious furniture moving [link] and so on. Yesterday I cut the hedges again, got rid of major amounts of stuff and moved a few hundred liters of green waste to the disposal with the body powered arm and really, the skin of my arm is not at all like what we see below – all is smooth and no problem. It is not the prosthesis as such that is a problem generally. It is the difficulty to achieve electrode fit and socket fit at once that really constitutes the “bionic” dilemma here, combined with hard lift and pull forces. Leg amputees can not understand from their own sockets, they experience different problems, not these. If it just was some simple body powered arms, or passive arms, we’d all be cool. Look, I am not saying “eeks, bad”. I am saying, why the pansy boy type of immature excitement over what really is still problematic and massively overpriced technology when it comes to “bionic” arms? And here: can you reflect on the deeper meaning of what “bionic” arm wearing may entail?

As it was, my arm just started to pain so much that I just had to take the prosthetic off.

1/2 an hour after removing myoelectric “bionic” prosthetic arm after wearing it for 10 hours

The skin is indented, relatively deeply, around the outside electrode. Also, there are swollen and red areas in the elbow region (socket rim) and at the stump tip (congestion).

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The stump is clearly congested at the distal half, and seriously compressed up above, with redness occurring in all regions of slightly reduced strain.

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The redness prevails for a while. As I type this now, over half an hour after taking these photos, the redness still prevails in the same extent and contrast. The congestive pressure of the socket is substantial, the pain is significant.


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The end of the stump contains serious reddening that does not just go away. Also, congestion such as this has a tendency to recur.

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The inside of the stump contains the imprint injuries of the inside electrode, along with a bit more congestion.

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7 hours after removing myoelectric “bionic” prosthetic arm after wearing it for 10 hours

The swelling and redness did increase, in fact. It is now seven hours after removing the prosthetic arm.

Towards the end of the stump, the arm is quite painful also at rest now.

The middle area of the forearm is ridiculously painful and sensitive on touch.


The back of the elbow side of the forearm seems to be somewhat abraded and bruised. This is not abnormal, but it illustrates to those that have no idea what their electronics and weight does to a forearm stump, to get an idea.

And, no, not after years or so does one “get used” to this. It burns, it is painful. Also there is one pressure blister.


And so here some concluding images.

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Questions to “bionic” researchers

Here are my questions to researchers that feel they need to further develop “bionic” prostheses.

1) Do you think you can at least somewhat understand why wearing a prosthetic arm is, at best, totally uncomfortable after a while? And at worst, it is totally uncomfortable right away? What, that is similarly uncomfortable, do you do that you can refer this to? In other words, are you walking in my shoes at all?

2) Do you understand why I really mean it when I say that any self respecting researcher needs to have tried this out for at least a few months, 10-12 hours every day? Including the really badly cramped muscles of neck, back, and shoulders? I am not talking about a muscle strain. I am talking about muscle cramps no massage therapist can get rid off even when focusing on one spot for one hour. I am talking industry sized pain. Do you understand why other prostheses, that are far easier on the skin and muscles, may be better? Or is it still beyond your comprehension?

3) I always say that socket technology needs to really evolve before “bionic” hands become a more serious option. Given these realities, how much “hammering home” do you think is required?

Voight-Kampff question to “ethics” researchers

The Voight-Kampff test is s fictional test in the Bladerunner movie.

It tests whether you are a replicant (i.e., a robot with human-like features) or a real human. This here has Voight-Kampff potential:

1) Were you to urge me to wear a “bionic” arm (given the above outcome) – what type of human does that make you? Does it make you a good human? Is that a human that you then become that you wish to be? Or in the Voight-Kampff dichotomy, are you a replicant?

2) Were I to voluntarily wear such an arm, I will suppress the most human feelings of  pain and restriction. Does that make me a lesser human? Is it me then, that is the replicant?

Quite possibly, we are drifting towards a world of considerably lesser empathy. Amputees are hailed to be the new super people by power of their new prostheses – but no one shows the above images, and no one tells the stories of these images.

Practical options

Wearing “bionic” myoelectric arm: by submitting my stump to an animalistic raw brutal mount system (i.e., prosthetic socket that keeps electrodes and socket in place) with the promised hope that that makes me (more?) human, I am a deeply torn and split individual that is neither a real animal (as that would feel far more natural), nor am I a better (or real) human according to the external appearance or functional measure. What I really am is suffering painwise, conceptually (replicant or not – you or me?), financially and timewise (the upkeep of these prosthetic arms is totally ridiculous) and due to astonishing lack of robustness and function. With the advantage of approximating a human appearance through a massively expensive promise.

Wearing split hook: when I wear my prosthetic hook, however, the body powered arm definitely improves my function. Also it feels very comfortable on the stump. Then I am foregoing  a superficially optimized human appearance approximation, but I avoid suffering concept wise, functionally, and the other aspects are tuned in a much better way too. Moreover, I can actually do stuff.

Further reading

The issue of skin rashes in context of myoelectric prosthetic arm usage / design / build is discussed in this article in depth:

Publication [link]

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Cite this article:
Wolf Schweitzer: - Stump after wearing myoelectric “bionic” prosthesis for 10 hours [graphic #voightkampff]; published 05/05/2014, 17:43; URL:

BibTeX 1: @MISC{schweitzer_wolf_1720907186, author = {Wolf Schweitzer}, title = {{ - Stump after wearing myoelectric “bionic” prosthesis for 10 hours [graphic #voightkampff]}}, month = {May}, year = {2014}, url = {}

BibTeX 2: @MISC{schweitzer_wolf_1720907186, author = {Wolf Schweitzer}, title = {{Stump after wearing myoelectric “bionic” prosthesis for 10 hours [graphic #voightkampff]}}, howpublished = {Technical Below Elbow Amputee Issues}, month = {May}, year = {2014}, url = {} }

2 thoughts on “Stump after wearing myoelectric “bionic” prosthesis for 10 hours [graphic #voightkampff]

  1. Hi, it is ridiculous that comfort isn’t priority number 1 over fancy gadgetry! Forgive me if you’ve posted this elsewhere, but what exactly is the difference between how the body powered and the myoelectric prostheses attach? Is that mainly what creates the discomfort, or is it the greater weight of the myo arm?

    1. The myoelectric arms require electrodes to always make contact with the stump at the same location. That entails a number of consequences such as less degrees of freedom for the elbow, different choices for suspension. The result is usually a hard socket that cannot at all comply to real life where stump volumes do change. That did not work at all for me. So I got a rigid custom liner with punched out holes to allow for socket mounted electrodes to touch the skin. Similarly there, as the socket preserves its shape and my arm does not, I may find my stump shrinked a bit (as it currently just did) and so currently I have absolutely no control over my myoelectric arm when I try to wear it – my stump has shrunk and the socket is too wide, can NOT control the electrodes. When it would be working, the liner edges would cause so much friction that the stump got seriously damaged. Lack of control, lack of comfort and lack of performance are well known serious problems of that technology and are a relevant reason not to wear them, or at least, not for any longer amount of time.

      Control wise and socket issues aside, the electrodes will cause involuntary signals to the hand for example when the elbow is flexed. That is another reason to avoid myoelectric arms for mission critical work.

      Last but not the least, the distal center of gravity plays a role. Not for the skin friction, at least not in my view. But for tense arm, neck and shoulder muscles. There, the awkward weight distribution caused me to consume more NSAID tables in a week than I otherwise need in a year. Only fairly bulky wrist adapters (I have a fairly long stump) are provided for myoelectric arms, so the arm then is usually too long, which adds considerably to my neck / shoulder problems.

      So when I already take shoulder /neck problems and low to absent hand control into account, I am a lot better off without the prosthetic on, as it is massively more comfortable, massively cheaper, and exactly as painful for the shoulder – however, there I can fix things by adapting my posture whereas with a 2kg added anchor, that is somewhat hard.

      The combination of these makes one hell of a trip. Summer here, no air condition.

      If you want to simulate this:
      – wear a few dozen tiny gravel type rocks under a VERY tight bandage on your hand and wrist and forearm, to cause stinging pain similar to phantom pain just to set an adrenaline base level; trust me, you do NOT want to play testing prostheses without phantom pain;
      – then you wrap the hand so you can only make open/close motions, barely; if the fingers do not feel a bit numb, tighten, to further increase adrenaline;
      – then tightly wrap the whole arm, up to the elbow or higher, with some thick neoprene; after all, you want to be sweating like someone that does wear a prosthetic arm, expect there to be skin rashes (normal for amputees!) and a permanent bad itch (normal) (adrenaline further up?);
      – then add a 2kg wrist band, that you can get at any decent sports outlet, to really show your elbow and shoulder as well as neck / back structures what is going on.

      Then, wear that for 10 hours a day, 7 days a week, six to eight weeks. Type hard, shop, cook, vacuum, go after it full blast. I am expected to go after it full blast, too. After that, reflect your experience. Now explain how that expanded your understanding that people stop wearing myo arms.

      Body powered technology has more degrees of freedom, technically, to easily play with for improvement. They are also a sweaty hot endeavour, but center of gravity can be optimal, control feel tight and precise, light and reliable; shoulder cable connection integrates with body motion far more easily and stump compression can be variable with a relaxed socket fit as all there is to suspension there is the pin lock, that can be fashioned to (lengthwise) overlap with the wrist unit. With that technology, I can wear an arm that is also not too long.

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