The relation of extraarticular tenderness to inflammatory joint disease and personality in patients with rheumatoid arthritis.

We measured the pain tenderness threshold at 16 fibrositic tender points in 44 consecutive patients with rheumatoid arthritis (RA) attending the outpatient rheumatology clinic of a university hospital. Pressure threshold measurements were transformed to z units to equalize the weights of the values at different anatomic sites and were then summed. This pain tenderness score correlated with the joint score index (p less than 0.02, r = -0.363), signifying a low pain threshold in the patients with a high joint score index. In contrast to this, the pain tenderness score was not explained by either personality factors or the generalized disease activity measuring variables (erythrocyte sedimentation rate, C-reactive protein). Our results show that the fibrositic point tenderness is real in RA, and that the tenderness is augmented near the active joints. The pain tenderness score of patients with RA is not affected by the subject's personality but may relate to sensitization of the pain fibers in arthritic joints.