New Instrument to Measure the Stiffness of the Finger Joints; StifMeter

ABSTRACT

OBJECTIVE: To examine the stiffness of finger joints with StifMeter among the patients with rheumatoid arthritis and to calculate the absolute value of the stiffness with a unit of power and to compare the values of the StifMeter with visual analog scale about stiffness (VASstiff). METHOD: Subjects were 53 rheumatoid arthritis patients (male 8, female 45) with disease duration at least 6 months. StifMeter was made up of 10 graded springs of a same spring-constant. Stiffness and pain by VAS and StifMeter, finger circumference and pinch strength were measured at outpatient clinic as well as questionaire, prospectively. Laboratory data were reviewed from medical records to verify the state of disease. We compared StifMeter with VASstiff and VASpain. RESULTS: Mean score of StifMeter was 5.59 on the right side and 5.53 on the left. The corrected values of the StifMeter with a unit of power were 0.01684 on the right side and 0.01672 on the left side. VASstiff score was positively correlated with that of StifMeter. The older the age, the higher the score of VASstiff that was positively correlated with that of StifMeter. The longer the duration of disease, the higher the score of VASstiff that was positively correlated with that of StifMeter. CONCLUSION: StifMeter is a semi-objective method which may be of value in the measurement of finger joint stiffness.