We report a detailed study of the relative distribution of joint damage, as assessed by erosion and joint space scores, in the proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints of the rheumatoid hand. Hand radiographs of 30 patients with erosive rheumatoid arthritis were studied.
There was significantly more damage in the dominant hand. The little-finger PIP joints were more damaged and the thumb interphalangeal (IP) joints less damaged than the other PIP joints. The index and middle finger MCP joints were more damaged than the other MCP joints. There was a significant negative correlation between the erosion scores of the PIP and MCP joints of each individual digit, when digits with only minimal damage were excluded.
These findings support the concept that joint damage in the rheumatoid hand is greater in those joints that are subjected to greater mechanical stresses, and that in any digital ray the damage is concentrated at either the PIP or MCP joint.