Facet Joints Involvement in Rheumatoid Arthritis: A Cross-Sectional Study

Abstract

Background: It has been accepted amongst rheumatologists that rheumatoid arthritis (RA) does not involve the facet joints (FJs) of the spine; nevertheless, the issue is still under debate. Objective: To compare the prevalence of FJs’ changes between patients with RA and age- and sex-matched peers. Methods: CT scans of 34 patients with RA suffering from low back pain (LBP) were compared with 70 age- and sex-matched controls (individuals without RA, suffering from LBP) in a case-control study. The degenerative changes in the FJs were evaluated (i.e., joint space narrowing, marginal osteophytes, articular process hypertrophy, subchondral sclerosis, inter-joint vacuum phenomenon, and subchondral cysts), in addition to the marginal erosions, the most characteristic feature of joint change in RA. Disease activity characteristics (CRP, ESR, DAS-28, SDAI, and CDAI), duration of RA, age, and sex were obtained from patients’ clinical charts. Results: The prevalence of FJs’ changes in patients with RA and age- and sex-matched controls were not significantly different at any spinal level or in a total L1-S1 score. Marginal erosions, a characteristic feature of joint changes in RA, were not found in any of our RA subjects. No difference was found in disease parameters and markers in individuals with RA with affected FJs and those without. The occurrence of FJs’ changes amongst subjects with RA demonstrated no correlation with disease duration and activity. Conclusions: FJs of the lumbar spine are not involved in the inflammatory process of RA, and their LBP is not due to inflammation in FJs of the spine.