WordNet (r) 3.0 (2006):

atrophic arthritis
    n 1: a chronic autoimmune disease with inflammation of the
         joints and marked deformities; something (possibly a virus)
         triggers an attack on the synovium by the immune system,
         which releases cytokines that stimulate an inflammatory
         reaction that can lead to the destruction of all components
         of the joint [syn: rheumatoid arthritis, atrophic
         arthritis, rheumatism]