I only have arthritis (among other places, like the neck and back) in the middle of finger of my right-dominant hand. But because I can’t close that finger all the way, this makes it difficult sometimes to pick up small things, such as an errant screw or and ice cube.
I have taken to using the index finger, but even that’s a chore sometimes.
But lately I have notice trouble screwing on bottle caps onto 2 liter bottles or a bottle of dressing, to the point where D takes out of my hands and does it for me, before I flip my lid, which I have done numerous times (right?:))
I’m sure it could be a number of things, right? Eyesight maybe being one of these?
Oh, yeah. Twisting the lid off something is also difficult, sometimes.
Arthritis of the basal joints in both thumbs here, and in my little fingers to a lesser extent. I used to have a grip of steel; now jar lids defeat me unless I have a tool to assist. I also tend to drop things more. Really pisses me off (and is painful, too).
The standard advice is to turn the cap in the reverse direction, to catch the thread more easily. Then turn it closed.
Try one of those dollar store gadgets meant to grip jar lids (hinged shaped metal strips) – usually has a bottle-cap size grip further down. It’s the leverage that does it.
If practical, sit down at a table to wrestle with these items. You can stand the bottle on the surface, and anything that you drop has a better chance of staying within reach.
If you have access to physiotherapy, ask for grip-strength exercises.
I’m not arthritic, but my mother has arthrosis and one of the things for which she uses the automagic tools called “children and grandchildren” is opening and closing bottles. When no children are available, she uses a triangular thing for opening jars and bottles (first you use it as a lever to break the seal, then you “sit” it on the cap and twist - the triangular shape means it’s one-size-fits-all); bottles are likely to stay uncapped.