First time posting here. I will post a intro separately. I have arthritis in my picking thumb. I use a trigger style grip however my thumb is permanently gnarled in a bent position. I am primarily an upstroke escaped player that uses a wrist forearm blend.
I have seen and read Troy and others mention that the thumb should be kept straight but since I cannot physically do this I am curious if I am being limited somehow.
Cheers.
If you can’t physically straighten your thumb, then it’s simply a matter of adapting that to your technique. Others know far better than I, but the purpose of a straight thumb is to limit the thumb joint’s ability to move during the motion.
I was (and still am) doing this depending on the situation.
I would suggest posting a video of your picking and let the teachers here comment. Its not a matter of one right way for everybody, it’s the right way for you.
Agreed, a video could be helpful!
The most important guiding principle, however, is that your picking should not feel painful.
Also, you should try to find a pick grip that does not require a lot of conscious effort to be maintained. The idea is that it should be possible to maintain the pick grip for long periods without fatigue.
For most people, this translates into a thumb joint that’s straight or just a little bent.
For the record, for whatever reason I personally have a hard time keeping the thumb completely straight. In my most used setup, my thumb is more or less like so:
My thumb is very, very similar to the above. However, my resting hand posture doesn’t include my index finger curling as much.
It’s a very personal thing, but when I do that…bad things happen for me. 
Aha!
Good point, I should clarify! I did not post that picture because I think everyone should grab the pick like me — quite the opposite! I just wanted to show that in my specific case the most relaxed thumb posture seems to be “ever so slightly bent”.
However, this is not to exclude that in the future I might find a different setup which feels good with a straighter thumb.
Welcome to the forum, @koolguy. Kool screen name too.
I agree with what the others have said.
Here is a case with a slight thumb bend, USX forearm motion. @qwertygitarr’s USX is arguably the best we’ve seen, certainly in terms of aesthetics, but also in terms of speed as he’s posted videos of 6’s in the 150 - 160 bpm range:
Since in your case, “it is what it is”, at least you know it doesn’t need to be a hindrance.
Musicians and it seems guitarists in particular have this idea that there is one way to hold a pick, one way to fret, one way to…etc. For a very long time, I was no different.
The analogy I’ll use deals with bicycles. A lifelong friend of mine is a professional bike fitter and mechanic. Bicycle fit is exceedingly personal and takes into account fitness level, physical size, limitations (flexibility, range of motion etc.)
The idea being the same as good playing technique. That is - to limit the amount of unnecessary effort required. edit: This includes proper muscle recruitment. Making small muscles do large efforts doesn’t work for very long.
The main difference is that for the most part, a bicycle is fitted to the rider. The technique is left predominantly static, while the instrument (bicycle) is molded. Fit changes as you age, suffer injury or as fitness improves (or declines).
For the most part, you don’t ‘fit’ a guitar to your physical playing structure. You fit your playing to the guitar to create the most relaxed and efficient setup.
I know very little of the what and how of either of these things. But I can tell you that even getting it even 10% more ‘right’ provides improvements you cannot believe.
Thanks Joe, and others. Great answers here and pretty much what I figured. I am very satisfied with my playing and progress since joining CTC. Nice to know there is no downside from more experienced players.
