POS0914 ULTRASONOGRAPHIC EVALUATION OF ENTHESEAL FIBROCARTILAGE IN PATIENTS WITH PSORIATIC ARTHRITIS, HEALTHY CONTROLS AND ATHLETES: A COMPARISON STUDY

Abstract

BackgroundEnthesitis is the hallmark Psoriatic Arthritis (PsA), with the entheseal fibrocartilage (EF) found to be the possible target tissue of inflammation [1]. With the development of feasible and more accurate imaging modalities, thein vivostudy of this important tissue has become more precise.ObjectivesThe aim of this study was: 1) to evaluate the EF at Achilles tendon insertion by using power Doppler ultrasound (PDUS) in PsA 2) to assess the intra and inter-reader reliability in the evaluation of EF thickness 3) to compare EF thickness of healthy controls (HC) and athletes; 4) to evaluate the association of EF abnormalities with other entheseal abnormalities and disease activity and functional indices in PsA.MethodsConsecutive PsA patients attending our unit with age < 50 years were asked to participate. HC and agonist athletes (basketball and soccer players with a minimum of 10 hours training per week) were enrolled as control group. Bilateral PDUS evaluation of Achilles tendons was performed in order to evaluate the EF in all patients and controls. EF was defined as the thickness of the anechoic layer just above the cortical bone and was measured at its thickest point in the longitudinal scan, as previously described [2]. All PsA patients underwent a complete clinical examination.Results30 PsA patients, 20 HC and 40 athletes were enrolled. Female/male ratio was balanced among the three group. Median age (IQR) was higher in PsA patient (49; 41-54) than HC (26; 21-29) and athletes (24; 21-27). Four (13.3%). No patients had clinical heel enthesitis. Median (IQR) EF thickness between PsA, athletes and HC was 0.035 (0.03-0.04) cm, 0.035 (0.03-0.04) cm and 0.03 (0.02-0.04) cm respectively (p=0.05 between PsA and HC; Kruskall-Wallis analysis, see Figure 1). The intra-reader reliability was excellent [intraclass correlation coefficient-ICC (95% confidence interval-CI) of 0.91 (0.88-0.95)] and the inter-reader reliability good [ICC (95% CI) of 0.80 (0.71-0.86)]. At PDUS, no statistically significant differences were found in entheseal abnormalities. However, 3 PsA patients showed erosions at entheseal site in respect to HC and athletes which did not show erosive changes.We did not find correlations between EF thickness and BMI, age, disease duration, disease activity (assessed by DAPSA), LEI and impact of disease (assessed by PsAID) and duration of sport activities in athletes. A trend toward a correlation between EF thickness and body weigh was found (Table 1).Assessment of EF was feasible with a mean time of 2 minutes.Table 1.Spearman’s rho correlations (by site) between EF thickness and clinical characteristics in Psoriatic arthritis (PsA) patients, healthy controls (HC) and athletes.EF thickness (right)rhoP valueAll (PsA+ HC+ Althletes)Age-0.1440.177Weight0.1930.072BMI0.1170.277PsA patientsDAPSA0.1940.364Disease duration (months)-0.1710.375LEI0.1090.545PsAID0.2320.234EF thickness (left)rhoP valueAll (PsA+ HC+ Althletes)Age-0.0910.398Weight0.1560.148BMI0.1490.165PsA patientsDAPSA0.0360.868Disease duration (months)-0.0940.635LEI0.1290.455PsAID0.0340.643BMI: body mass index; DAPSA: disease activity index for psoriatic arthritis; LEI: Leeds enthesitis index; PsAID: psoriatic arthritis impact of diseaseConclusionThe assessment of EF is a feasible and reproducible test. Furthermore, our data suggest an increased thickness of EF in PsA patients in respect to HC with similar values in respect to agonist athletes and may open the way to further large studies on this peculiar aspect.