Axial radiographic structural damage in patients with Enthesitis-Related Arthritis presents a distinct phenotype compared to adults with axial spondyloarthritis: A cross-sectional cohort study.

Enthesitis-related arthritis (ERA), a distinct subtype of juvenile idiopathic arthritis (JIA) related to HLA-B27 and peripheral and axial involvement, presents with insidious onset of arthritis and/or enthesitis. However, there is a lack of data concerning axial new bone formation in patients transitioning into adulthood. To evaluate the axial radiographic structural damage (axRxSD), encompassing the sacroiliac joints (SIJ), hips, and spine, in ERA patients across various age groups.