RT Journal Article SR Electronic T1 Ultrasound definition of enthesitis in spondyloarthritis and psoriatic arthritis: arrival or starting point? JF Annals of the Rheumatic Diseases JO Ann Rheum Dis FD BMJ Publishing Group Ltd and European League Against Rheumatism SP annrheumdis-2021-220478 DO 10.1136/annrheumdis-2021-220478 A1 Emilio Filippucci A1 Gianluca Smerilli A1 Andrea Di Matteo A1 Walter Grassi YR 2021 UL http://ard.bmj.com/content/early/2021/06/25/annrheumdis-2021-220478.abstract AB Enthesitis has a key role in the diagnosis, classification and management of patients with spondyloarthritis and psoriatic arthritis. Clinical assessment of enthesitis is known to be inaccurate mainly due to its poor specificity. In this context, ultrasound has the potential to improve the evaluation of enthesitis and, therefore, the management of patients with spondyloarthritis and psoriatic arthritis. In this viewpoint, we review the Outcome Measures in Rheumatology (OMERACT) definitions for ultrasound enthesitis, highlighting their current limits and potential implications on rheumatology research and clinical practice.