THU0394 Enthesitis in systemic sclerosis (SSC): an ultrasound (US) pilot study
Authors: R. Terenzi, R. Karalilova, S. Bellando-Randone, S. Guiducci, M. Manetti, E. Romano, D.E. Furst, G. Pacini, A. Batalov, M. Matucci-Cerinic
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Articular involvement is frequently encountered in SSc and previous US studies suggest that synovitis is the commonest manifestation. Recently, it has been reported that SSc patients may show typical "hall-marks" of spondyloarthritis (SpA). Apart from tendon involvement which is a common event, sacroiliitis has been estimated to have a prevalence of 23%. <h3>Objectives</h3> To estimate the prevalence of entheseal and Synovio-Entheseal Complex (SEC) modifications in SSc <h3>Methods</h3> 30 SSc patients (2013 ACR/EULAR classification criteria) without a history of articular involvement (4 male, 26 female, mean age 53,3±16,6 years) were included in this pilot cross sectional US study. 12 healthy subjects (2 male, 10 female, mean age 46,9±5,8 years) were used as controls. The entheseal sites were the lateral epicondylar common extensor tendons (CET), and sites of the Glasgow Ultrasound Enthesis Scoring System. The GUESS score was also calculated as a soft tissue score (GUESS soft tissue) and as a bone score (GUESS bone). US assessment was performed with a MyLab 70XVG scanner equipped with a 6–18 MHz linear transducer (Esaote). Only the epicondylar region was evaluated with PowerDoppler US (PDUS), using semi-quantitative graded from 0 to 3. Involvement of SEC was evaluated at the epicondylar region in SSc patients who presented a PDUS signals≥1 in the CET closer than 2 mm from the bony surface. SEC involvement was defined as the presence of a PDUS signal ≥2 in the elbow epicondylar synovial fold proximal to the annular ligament (AL), inferior to the bone insertion of CET and to the radial collateral ligament (RCL). Statistical analyses were carried out using Mann-Whitney U, Spearman correlation and Chi-square tests. Results were considered significant if p&lt;0,05 <h3>Results</h3> In SSc, the GUESS and GUESS soft tissue scores were significantly higher (5.67±0.87 and 3.43±0.44, respectively) than in controls (1.25±0.41 and 0.92±0.29, respectively) (p&lt;0,0001) as was the GUESS bone score (SSc 2.23±0.55 vs controls 0.33±0.22; p&lt;0,05). The CET entheses of SSc patients showed significantly more US B-mode alterations than controls (hypoechogenicity χ<sup>2</sup>=5.95, p=0.015, cortical irregularity χ<sup>2</sup>=7.90, p=0.005, calcification/enthesophytes χ<sup>2</sup>=3.78, p=0.05). A PD signal in the CET enthesis was found in 18/60 sites in SSc and in 1/24 in controls. The PD signal of the CET enthesis was significantly higher in SSc patients than in healthy controls (0.47±0.10 and 0.08±0.08 respectively, p=0.018) as was the presence of SEC inflammation (χ<sup>2</sup>=4.54, p=0.033). In SSc, there was a strong correlation between the presence of PD signal at CET entheses and concomitant SEC inflammation (rho=0.655, p&lt;0.0001) but there were no correlations between GUESS score or CET enthesitis and disease sub-set, disease duration, antibodies, DLCO, FVC, DLCO/VA. <h3>Conclusions</h3> Our data show that SSc patients frequently present the usual US features of enthesitis. Moreover, CET enthesitis were correlated with SEC inflammation suggesting that entheseal inflammation in SSc may share same microanatomical targets as SpA. <h3>Disclosure of Interest</h3> None declared