Radiological cervical spine involvement in polyarticular idiopathic juvenile arthritis

erosions of the odontoid process (34%) and atlanto-axial impaction (20%). Apophyseal joint ankylosis (AJA) was rare (10%) but involvement of the posterior cervical spine (AJA and apophyseal joint arthritis) was more frequent (42%). Presence of radiographic cervical lesions was correlated in univariate analysis with a more severe disease phenotype: more erosive disease (hand and feet), higher number of biotherapies per patient (respectively 1.4±1.3 vs 0.5±0.5, p=0.003), and higher frequency of surgery (p=0.03, OR 7.74[0.92-65]) but not with RF status. Multivariate analysis confirmed only the association with the higher number of biotherapies per patients (p=0.04). 50% of pJIA with radiographic abnormalities had no clinical symptoms. In pJIA sub-group with cervical symptoms (n=24), patients needed more DMARDs and biotherapies per patient. Finally, comparison between pJIA and RA for radiographic findings showed only differences for two structural features: hypotrophy of vertebrae (24% vs 7%) and AJA (10% vs 0%). Conclusion Structural cervical spine involvement is a frequent manifestation in pJIA followed at adulthood and is correlated with a more severe disease. Radiologic assessment of cervical spine should be done systematically at onset and regularly during the course of the disease regardless of clinical symptoms. Cervical symptoms may be considered as a warning signal revealing presence of AJA.