Figure 4

Altered thresholds for mechanosensation (A) and pain (B) in patients with rheumatoid arthritis and osteoarthritis. (A) Mechanical sensation thresholds (g) for normal (Norm), rheumatoid arthritis (RA) and osteoarthritis (OA) patients, determined by von Frey monofilament testing. The RA and OA groups had significantly higher average mechanical sensation thresholds in both knees. Monofilament diameter scores for each knee were converted to grams per protocol convention for threshold determination. Average and standard error mechanical sensation scores for both knees and for the most symptomatic (worst) knee are demonstrated. * P < 0.05 when compared to normal controls, analyzed by paired and unpaired Student t-tests. (B) Mechanical pain threshold scores (g) for Norm, RA and OA patients, determined by von Frey monofilament testing (see A). The average pain threshold for both knees and for the most painful (worst) knee was significantly lower in RA patients than in the Norm group. The average pain threshold for both knees and for the most painful knee in OA patients was significantly lower than in the Norm group. * P < 0.05 when compared to normal controls, analyzed by paired and unpaired Student t-tests. Reprinted from [59], Copyright 2003, with permission from Elsevier.