We don’t really know…and to be honest we have little clinical evidence to say that they have any effect whatsoever. However I’ll outline some of the work done:
A single study in 1976 looked into this and determined that a significant number of people using the copper bracelets felt a positive effect on their condition vs wearing a placebo bracelet made of aluminum. They also found that over 50 days a copper bracelet worn around the wrist lost about 90 mg.
A 1983 study in animal models showed that arthritic rats would preferentially increase their intake of a solution of Copper Salicylates, suggesting that it had an analgesic effect on condition. The same team looked at the potential for copper to form ligands with the contents of human sweat and to permeate through the skin and found that it was plausible in an animal model.
It appears then that their use might be plausible. I don’t think there would be any toxic side effects to their use – Wilson’s disease is a disease of copper metabolism and there is no chance that the copper from these bracelets could lead to anything like that.

My father was a BIG believer in this. I got diagnosed with arthritis when a teenager and he gave me one of his bracelets I still have today. Though I stopped wearing it. I do not like wearing anything such as jewelry.
For my father it was a traditional thing one just did. His parents did it, his grandparents did it there for he did it and thought I should do it.
Crystals, certain minerals are supposed to help us. We are made of energy, water, and those who have been raised to believe in this sort of thing it might just work (my father passed away some time ago).
I will keep an eye on your answer, so I too can get smarter…