Findings: These are images of the right and left hand demonstrating a diffuse interphalangeal joint space narrowing bilaterally with both osteophytes and erosions. A centrally located erosion can be identified involving the left fourth middle phalanx. In addition to the osteophytes and joint space narrowing, there is subchondral sclerosis. Many of the proximal interphalangeal joint spaces have a "seagall" appearance. The carpal bones and carpometacarpal joints as well as the metacarpophalangeal joint are relatively uninvolved.

Diagnosis: Erosive "inflammatory" osteoarthritis.

Discussion: Erosive osteoarthritis is a disease entity which is most common in middle-aged females. The disease is characterized by acute articular attacks resembling rheumatoid arthritis, although other peripheral joints are unaffected and the serologic tests for rheumatoid factor are negative. The onset of the disease may be abrupt as with painful nodules identified along the distal and proximal interphalangeal joints in association with edema and tenderness. The distribution of the disease is symmetric with the interphalangeal articulations most commonly involved. The course of the disease is quite variable.

The radiologic findings are characterized by the combination of findings suggestive of osteoarthritis as well as findings suggestive of rheumatoid arthritis. That is, there are commonly findings consisting of both bony proliferation and erosion. There will typically be joint space narrowing as well as associated subchondral sclerosis and osteophytosis. In contradistinction to osteoarthritis, erosions are a common manifestation of erosive (inflammatory) osteoarthritis. The erosions most commonly begin in the central portion of the articulation which differs from the marginal erosions seen in rheumatoid arthritis. Central erosions are characteristic of erosive osteoarthritis. These are sharply marginated and located primarily within the interphalangeal joints. In severe cases, there may be bony ankylosis at the interphalangeal joints. Occasionally, erosive osteoarthritis may be mistaken for psoriatic arthritis. In contrast to erosive osteoarthritis, psoriasis demonstrates no osteophyte formation. Less commonly involved joints include the metacarpophalangeal and first carpometacarpal articulations.

Reference:
Brower A. Arthritis in Black and White. 2nd edition. W. B. Saunders,
Philadelphia. 1997;277-279.

Resnick D. Bone and Joint Imaging. W. B. Saunders, 2nd Edition, Philadelphia.
1996;1465-1469.

Return to Musculoskeletal Teaching File Page