Predictors factors of atlanto-axial subluxation in Tunisian patients with rheumatoid arthritis.

Background: The aim of this study was to describe clinical and imaging features of atlantoaxial subluxation (AAS) and the associated risk factors in patients with rheumatoid arthritis (RA).

Methods: We conducted a retrospective and comparative study including 51 RA patients with AAS and 51 RA patients without AAS. Atlantoaxial subluxation was defined by the presence of an anterior C1C2 diastasis on the cervical spine radiograph in hyperflexion and/or an anterior, posterior, lateral or rotatory C1C2 dislocation on MRI with/without inflammatory signal.

Results: In G1, clinical presentations revealing AAS were mainly neck pain (68.7%) and neck stiffness (29.8%). MRI revealed: diastasis C1C2 (92.5%), periodontoid pannus (92.5%), odontoid erosion (23.5%), vertical subluxation (9.8%) and spinal cord involvement (7.8%). A collar immobilisation and corticosteroid boluses were indicated in 86.3% and 47.1% of cases. C1-C2arthrodesis was performed in 15.4% of cases. Atlantoaxial subluxation was significantly associated with: age at disease onset (p = 0.009), history of joint surgery (p = 0.012), disease duration (p = 0.001), rheumatoid factor (p = 0.01), anti-cyclic citrullinated peptide (p = 0.02), erosive radiographic status (p < 0.005), coxitis (p < 0.001), osteoporosis (p = 0.012), extra-articular manifestations (p < 0.001), and high disease activity (p = 0.001). Multivariate analysis identified RA duration (p < 0.001, OR = 1.022 CI[1.01-1.034]) and erosive radiographic status (p = 0.01, OR = 21.236 CI[2.05-219.44]) as predictive factors of AAS.

Conclusion: Our study showed that longer disease duration and joint destruction are the major predictive factors of AAS. Early treatment initiation, tight-control and regular monitoring of cervical spine involvement are required in these patients.