The Metacarpophalangeal Joints in Interphalangeal Osteoarthritis

Case material and roentgenograms of 30 patients with interphalangeal osteoarthritis and 30 with rheumatoid arthritis were studied in an effort to determine if the two diseases could be differentiated radiographically. Narrowing of the interosseous spaces of the interphalangeal joints is commonplace in osteoarthritis, and, because it is characteristically uniform and may involve all of the metacarpophalangeal joints, it is easily confused with rheumatoid arthritis. An important distinction is that marginal erosions virtually never occur in these joints in osteoarthritis but are characteristic in rheumatoid arthritis. Although occasionally one or two metacarpophalangeal joints may be narrowed in rheumatoid arthritis without marginal erosions, it is unusual to find no marginal erosions in the presence of widespread metacarpophalangeal joint space narrowing.