That must be sooooo frustrating!!!
I had a look at both Spikey's links and they're brilliant ideas - if the clamp holds objects vertically and
horizontally, then probably you could get the best angle to suit you for the left needle, as in the photo.
I've bookmarked the clamp link because it might come in handy for when my arthritis plays up in my left wrist.
Anyway, good luck with the arm and I hope it will be better before too long - let us know how you get on, would you?
Thanks very much indeed, Spikey, for those two great links
All the Best