In certain forms of medicine, there sometimes is a focus on various qualities in the body, like moisture, dryness, heat, cold, etc. Osteoarthritis sounds like it would have something to do with lack of moisture—maybe not literally that the joints are dry, but that this quality of moisture is less present (if that makes any sense? It does to me)
Part of it might be resting the hands and making sure they have time to recover, and nourishing the kidneys, said to govern the body’s water. I don’t think sleeping well could be a bad thing, or drinking sufficient fluids, which might be broth or a nourishing tea. Both of those are rather moistening to the body.
Thinking more, horsetail keeps popping into my mind, which has a reputation for being good for connective tissue, and not only that but also is supportive of the kidneys. There is some information on my favorite websites, which supports the idea of using it for supporting the joints:
https://pfaf.org/user/Plant.aspx?LatinName=Equisetum+arvense
http://naeb.brit.org/uses/search/?string=Equisetum
I found it interesting to hear about native Alaskans harvesting large quantities of horsetail to feast on the stem juice. I tried last year and it is delicious! The plant reminds me via the doctrine of signatures makes me think of synovial fluid, and the overall jointed nature of the plant. Not that I am pushing or recommending the plant—I don’t have experience of using them for osteoarthritis. It could be something to try with further research and if it feels right.