As I understand it, both Grave’s and arthritis are classed as auto-immune disoders. ie., they occur as a result of the body’s immune response to itself! In the case of Grave’s and rheumatoid arthritis, the elements that trigger the unwanted immune reaction in both diseases are closely associated genetically, ie. they are very close together on the genetic ‘strand’. I wonder if this means that, if you have one of these diseases you are more likely to develop the other? I was diagnosed about 8 years ago (post-op now) and do experience some pain in knee joints and back and shoulder at times.