osteoarthritic changes

Hello,
I work in an outpatient facility coding radiology and some of the radiologists like to use the term osteoarthritic changes. I don't take this as being arthritis so I asked my supervisor and she told me that I can code arthritis because the patient already has it but it is not anywhere in the record. There is another coder who also codes osteoarthritic changes as arthritis. Would this be considered the beginning of arthritis and how would it be coded? Does anyone know of a specific citation in coding clinic or anywhere else about this situation?
Thank you

re: osteoarthritic changes

If there is osteoarthritic changes I would say patient has the condition. http://www.fortherecordmag.com/archives/ftr_02192007p38.shtml