Bony ankylosis in rheumatoid arthritis. Associations with longer duration and greater severity of disease.

Hand and wrist radiographs of 203 patients with rheumatoid arthritis were examined for bony ankylosis. Forty-eight patients (23.6%) showed ankylosis, including 34 with more than one joint fused. The distribution of ankylosed joints was 32.4% midcarpal, 29.5% common carpometacarpal, 15.8% radiocarpal, 15.8% proximal interphalangeal, and 6.5% metacarpophalangeal. Patients with ankylosis had significantly higher radiographic erosion, joint space narrowing, and malalignment scores than those without ankylosis (all P less than .001). Patients with ankylosis had significantly longer duration of disease (P less than .001) and physical examinations showed more limited motion and deformity (both P less than .001). More patients with ankylosis had subcutaneous nodules (P less than .05). Functional testing with grip strength and the button test revealed poorer performance in patients with ankylosis (both P less than .001). Questionnaires revealed patients with ankylosis had more difficulty with activities of daily living (P less than .001) and had more limited activity (P less than .01); physicians estimated more limited functional capacity (P less than .001). Thus, radiographic bony ankylosis was a relatively common feature of rheumatoid arthritis, and a marker of patients whose disease was clinically, radiographically, and functionally more severe.