This article is from the Canine Medical Information FAQ, by Cindy Tittle Moore with numerous contributions by others.
DJD = Degenerative Joint Disease (osteoarthrosis): DJD is a
degeneration of cartilage that can either occur as a primary condition
in older animals as a result of normal wear & tear, or as a secondary
condition to any other condition that affects a joint and surrounding
structures. It is not an inflammatory condition, as opposed to
infectious forms of arthritis or immunologic forms of arthritis
(rheumatoid arthritis or systemic lupus erythramatosus).
DJD can be ruled out with radiographic analysis such as OFA or Wind