Cervical Spine Involvement in Rheumatoid Arthritis: Does Joint Erosion Severity Correlate with Instability?

Abstract

Objectives: Although numerous risk factors associated with cervical spine involvement (CSI) have been reported in the literature, the relationship between the severity of peripheral joint erosions and CSI has not yet been investigated. In this study, we aimed to investigate this relationship.

Materials and Methods: Adult rheumatoid arthritis (RA) patients with a disease duration of more than 5 years were enrolled from 2 tertiary rheumatology clinics. Medical records were retrospectively reviewed. Neutral, open-mouth anteroposterior, full flexion, and full extension cervical spine radiographs, along with hand radiographs, were assessed independently by 2 blinded rheumatologists. “RA-type joint involvement (RJI)” was defined as presence of any erosion or joint space narrowing (JSN) as per the Modified Sharp Score (MSS). “Severe joint involvement (SJI)” was defined as presence of any erosion with a score of ≥ 3 points or JSN with a score of ≥ 4 points as per the MSS.

Results: We enrolled 238 patients, 84.5% of whom were female, and the mean age was 58.1 Å} 12.1 years. The frequency of CSI was 19.7% (n = 47), including anterior atlantoaxial subluxation (AAS) (42.3%), posterior AAS (7%), lateral AAS (22.5%), vertical subluxation (11.5%), and subaxial subluxation (12.7%). The CSI-positive group had longer lag time to diagnosis (P = .028), longer disease duration (P = .002), higher rates of RJI (P = .047), SJI (P < .001), and peripheral joint ankylosis (PJA) (P < .001) than CSI-negative group. In multivariate analysis, only PJA remained an independent predictor of CSI (P < .001). In addition, there was no significant difference in the frequency of interstitial lung disease and chronic knee/elbow arthritis between the CSI-positive and CSI-negative groups.

Conclusion: To our knowledge, this is the first study to identify PJA as an independent risk factor for CSI. Therefore, RA patients having PJA should be carefully screened for CSI.