Background/Purpose: Enthesitis is a characteristic feature of spondyloarthritis (SpA). Clinical evaluation of enthesitis by palpation is subject to differences in pressure used at different sites or by different examiners over time. Use of a dolorimeter allows calibration of the exact pressure used in assessment of tenderness. The purpose of this study was to assess agreement between manual and dolorimetric testing of entheseal points in juvenile SpA (JSpA).

Methods: Patients less than 18 years of age and diagnosed with JSpA based on ILAR criteria for ERA (over 75%), and Psoriatic arthritis and ESSG criteria for undifferentiated arthritis were included in the study. Forty JSpA patient encounters (age range 7-18 y) and 10 healthy controls (range 10-25 y) were included in the study. Thirty-three entheseal sites were assessed by manual palpation followed by dolorimetry by the same examiner. Three different examiners participated in the study. Tenderness elicited at less than 4 kg pressure using a 20 lb dolorimeter was considered positive by dolorimetry; tenderness with thumb pressure with blanching of the examiner’s nail bed was considered positive by manual palpation. Kappa statistics were performed by SPSS to assess agreement between manual and dolorimetric testing. Kappa value (k) > 0.6 indicates substantial agreement; 0.41 < k < 0.6 is considered moderate, and 0.21 < k < 0.4 shows fair agreement.

Results: The table displays kappa values for all 33 entheseal sites indicating the degree of agreement, for all 40 JSpA encounters. Substantial agreement between manual and dolorimetric assessment was noted in 42% of sites (14/33); moderate agreement was seen in 39% of sites (13/33) and fair agreement in 12% (4/33). Kappa values of corresponding right and left entheseal sites showed no statistical difference (paired t-test = 0.6). Of a total of 10 positive entheseal sites by manual palpation and 5 sites by dolorimetry in the 10 healthy controls, only one entheseal site showed agreement by both methods. Similar analysis on 30 adult SpA patients yielded 57% sites with substantial and 15% with moderate agreement.

Conclusion: There was substantial to moderate agreement between clinical enthesitis evaluation by manual and dolorimetric methods in 81% of sites, with fair agreement in another 12% in JSpA. Since a single exam was performed at each visit, inter-rater reliability was not assessed. Although manual testing standardized for nail blanching and dolorimetry exhibited considerable agreement, use of dolorimetry may enhance objectivity for enthesitis evaluation among JSpA patients in clinical trials. Future studies are needed to address inter-rater reliability between the two methods and to correlate with ultrasound and/or MRI.