Lack of objective evidence of stiffness in rheumatoid arthritis

SUMMARY Metacarpophalangeal joint stiffness was measured using a new microprocessor controlled arthrograph in 135 patients with rheumatoid arthritis. Subjects were prospectively subdivided according to the stage of the disease in the joint. Compared with a normal population stiffness variables in active rheumatoid arthritis were decreased, significantly so for non-elastic stiffness. This study casts doubts on the literal interpretation of symptomatic stiffness as an indicator of disease activity in rheumatoid arthritis and suggests a number of explanations for the discordant result. Key words: joint stiffness, microprocessor. Symptomatic stiffness heads the list of diagnostic criteria in rheumatoid arthritis (RA). ' A number of attempts to quantify this symptom have been made over the last 25 years following the original work of Wright and Johns2 and have, on the whole, tended to confirm the patients ' impression that physical stiffness is increased in RA. We have challenged this belief, indicating possible sources of error in pre-vious methodologies.3 A further source of confusion may arise if patients with RA are treated as an homogeneous group. The physical characteristics of an architecturally normal joint affected by an inflammatory synovitis are likely to be different from those of a joint whose structure has been completely disorganised by the rheumatoid process. We have prospectively subdivided patients with RA affecting the hands into four distinct subgroups, according to the stage to which their disease has progressed, and have compared stiffness values in these subgroups with those of the normal population. Patients and methods Stiffness was measured in the third metacarpopha-langeal (MCP) joint of the dominant hand with the Leeds microprocessor controlled arthrograph.