Im clearly a fan of Iodine but the problem is much bigger. Most people dont get enough selenum, boron, vit A, vit K, vit C, lysine, magnesium, potassium to name just a few.
A lot of Arthritis problems are overall general malnutrition combined with heavily skewed nutrient ratios. For example people get WAY more calcium than they need and not enough A, K and C.
Without the ample A, K, C and D (which of course requires magnesium), excess calcium is a slow killer and calcifies joints (ie arthritis) and arteries (ie arteriosclerosis).