I don't remember any percentages of RA, shown on the MRI report..i would go by whats on the pathology report, they sent away samples of your tissue, or whatever they took out. I had to get that report, for the ortho to look at, before he did my knee replacement. My older brothers, both of them had knee replacements, and they have OA, and i have RA.
Hope the arthoscopic has helped you, and your giving yourself some time to recover...i'm sure you will be sore for a couple weeks, hope your pain is ok, and that the procedure has helped you