The GRAPPA Sonographic Enthesitis Workshop.

Enthesitis is a key feature in psoriatic arthritis (PsA) and may be the initial site of musculoskeletal inflammation in patients with PsA. Ultrasound (US) could improve the accuracy of clinical enthesitis assessment, but at present no consensus exists on a global sonographic enthesitis scoring method that can evaluate the extent of enthesitis at the patient level. The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) US Working Group has set up a goal to optimize the evaluation of enthesitis in patients with PsA using US through the development and validation of new instruments using a combined data-driven and expert opinion-driven approach. This article summarizes the GRAPPA US Working Group's recent activities and focuses on a 2-day workshop that the group held following the annual 2018 GRAPPA meeting in Toronto, Ontario, Canada.