Objectives Clinical versus ultrasound evaluation of peripheral enthesites in a cohort of spondyloarthritis

Methods A monocenter prospective study of all SpAs ≥18 years meting the ASAS criteria for SpA followed in a rheumatology center over a period from January 2015 to April 2016. Demographic, clinical, lab and ultrasound characteristics were noted. Fifteen entheseal sites were investigated bilaterally: insertions of supra-spinatus, sub-scapular, medial and lateral epicondylar tendons, triceps brachialis, gluteus medius, quadriceps proximal and distal insertion (patellar ligament, medial and lateral collateral ligament), Achilles tendon, plantar aponeurosis. These sites were assessed clinically and with US during the same visit and then results were compared between the clinical and the US examination.

Results A total of 208 patients were included, mainly men (63.5%). The mean age was 40.2±11.7 years and the mean duration of the SpA was 11.8±8.7 years. Axial radiographic SpA was the most frequent phenotype (69.2%) and ankylosing spondylarthritis was the most frequent sub-group (57.7%). At examination, 88.9% had an active disease (ASDAS-ESR and/or ASDAS-CRP>1.3) and 64.4% of SpAs were taking NSAID. Clinical examination and US revealed at least one abnormal enthesis in 55.3% and 86.1%, respectively. Overall, 6240 entheses were examined, 44.2% were considered abnormal by clinical examination and 83.2% by US. The US abnormalities were entesophytes (69.5%), erosions (54.8%), hypochogenicity (49%), thickening (46.4%), bursitis (30.5%), calcifications (20.9%) and finally Doppler signal near the cortical bone in 20% of the examined entheses. The evidence of entheseal abnormalities by clinical examination has a poor likehood ratio (LR) for the presence of any US abnormality (LR + =1.4, LR- =0.8), for the acute US abnormalities (LR + =1.25, LR-=0,8), for the chronic US abnormalities (LR + =1.3, LR =0.8) as well as for the presence of the Doppler signal (LR + =1.1, LR- =0.9) at all sites.

Conclusions US is useful to detect structural and inflammatory abnormalities of the enthesis in the SpA and can complete physical examination in order to better evaluate enthesitis.

Disclosure of Interest None declared