It's a traditional remedy and considering the apple has been given special status in some societies and religions, the hype may be based on superstition. I drink a few drops of apple cider vinegar in a glass of water several times a day. Yes, it seems to help my arthritis, no, I'm not sure if its the placebo effect, but, because it works, I don't care.
Here's some info from Dr Mercola:
One possible explanation for apple cider vinegar's health benefits is its high concentrations of acetic acid. Like other acids, acetic acid can increase your body's absorption of important minerals from the foods you eat, such as green leafy vegetables.
Read more in this article on what the research really says about apple cider vinegar
the article also cites research suggesting that apple cider vinegar may lower blood glucose levels. Good luck, I hope it or something else can ease the pain of your arthritis.