Pathways of destruction in metacarpal and metatarsal joints of patients with rheumatoid arthritis.
219 metatarsal (MTP) and 69 metacarpal (MCP) capitulae obtained during surgery from patients with definite rheumatoid arthritis (RA) were histologically evaluated. This evaluation, focussing on primary pathways of joint destruction by tumor-like proliferated synovial cell masses revealed 3 pathways of aggression: Pathway A: In 15% aggression onto the articular cartilage only. Pathway B: In 49% direct invasion exclusively into the cortical bone. Pathway C: In 36% a "forceps-like" aggression, a combination of A and B in which the joint is attacked from both sides. In contrast to the hitherto conventional concepts, the findings of this study reveal a clear preference of the synovial aggression for the cortical bone rather than for the articular cartilage. The different concepts of joint destruction in RA are being discussed in the light of our findings. Thus, future pathogenetic considerations with regard to joint destruction in RA should take this fact into consideration.