Osteo Arthritis – What Treatment Will My Doctor Offer? The term arthritis does not refer to a single disease, but rather to a group of over 100 different forms of a disease, and in other words it is a sort of umbrella term that is used to refer to these medical conditions that affect the musculoskeletal system, specifically those joints where two or bones meet.While there could be over one hundred different types of arthritis and those are just the ones known and recognized at this time