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. 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.