Erosive (inflammatory) osteoarthritis

68 yo with bilateral hand pain

Osteoarthritis, the most common type of joint disease. It is a degenerative disorder that results from the biochemical breakdown of articular cartilage in the synovial joints. Historically, osteoarthritis has been divided into primary and secondary forms. The etiology of primary osteoarthritis is unknown. Secondary osteoarthritis refers to degenerative disease of the synovial joints that results from some predisposing condition, usually trauma. Primary osteoarthritis include primary generalized osteoarthritis, erosive inflammatory osteoarthritis, and chondromalacia patellae. Erosive (inflammatory) osteoarthritis is marked by a greater degree of inflammation. The disease most commonly occurs in postmenopausal women, and it may be hereditary. Erosive osteoarthritis is typically bilateral and symmetrical, and it occurs in the interphalangeal, particularly distal interphalangeal, joints of the hands. Rarely, patients may have erosive osteoarthritis at the base of the first metacarpal or even in the feet.
The radiologic findings are characterized by the combination of findings suggestive of degenerative (new bone formation ie. osteophytes) and inflammatory (erosions) arthropaty. The erosions are centrally located in contrast to the marginal erosions in rheumatoid arthritis. Joints assume a gull-wing configuration, with central erosions flanked by raised lips of bone. Periarticular soft-tissue swelling is evident. Osseous fusion, may occur.

Suggested Reading:
Resnick D. Bone and Joint Imaging. W. B. Saunders, 2nd Edition, Philadelphia.
1996;1465-1469.
Brower A. Arthritis in Black and White. 2nd edition. W. B. Saunders, Philadelphia. 1997;277-279.