Ankylosis of the wrist bones in patients with rheumatoid arthritis: a study with extremity-dedicated MRI.

Ankylosis, or spontaneous bone fusion, of the small joints of the hand is a rare event in patients with rheumatoid arthritis (RA), being observed in 0.8% of them on conventional radiographs. It is associated with long-lasting and severe disease. In other settings, such as fracture healing, bone fusion is a reparative process. The aim of this paper is the study of the frequency of wrist ankylosis in patients with RA in comparison with other arthritides; to correlate ankylosis with disease activity.A total of 94 patients affected by RA, 71 patients with different rheumatic conditions and 42 controls with no joint disease or with slight hand osteoarthritis were studied. DAS-28 CRP was calculated in patients with RA and psoriatic arthritis. MRI of the clinically most involved wrist was performed with a 0.2 T, extremity-dedicated MRI system.Of RA patients, 10/94 (10.6%) showed ankylosis in comparison with 2/113 (1.8%) controls (p=0.015). RA patients with ankylosis had longer disease duration (p=0.019) but similar disease activity.MRI-defined bone ankylosis is frequent in RA. It is not limited to seronegative spondyloarthritides and may be part of the bone damage observed in RA.