The following is a summary of “Prevalence and Associated Factors of Facet Joint Ankylosis in Patients With Axial Spondyloarthritis,” published in the June 2023 issue of Rheumatology by Lee et al.

The purpose of this study is to examine the prevalence of facet joint ankylosis in the entire spine in patients with axial spondyloarthritis (axSpA) using low-dose computed tomography (LDCT) and to identify factors associated with facet joint ankylosis. Two readers evaluated the presence of facet joint ankylosis (right and left, C2–S1) in 161 patients with axSpA using LDCT images of their entire spines (C2–S1). From 0 to 46, facet joint ankylosis was assessed. 

CT Syndesmophyte Score (CTSS) was utilized to evaluate structural damage to the vertebral body. A generalized linear model with a negative binomial distribution identified factors associated with ankylosed facet joint scores for the whole spine. About 79% of patients and 43% (reader 1 and reader 2, respectively) had at least one ankylosed facet joint. Ankylosis of the facet joints was most prevalent in the thoracic spine. The mean score for facet joint ankylosis was 6.6 (SD 11.2) for the entire spine in reader 1 and 4.2 (SD 8.4) in reader 2. Ankylosis of the facet joints of the entire spine was positively correlated with the Ankylosing Spondylitis Disease Activity Score (ASDAS) and CTSS. 

According to multivariable analysis, the ankylosed facet joint score was associated with ASDAS, sacroiliitis, CTSS, and a history of uveitis in both readers. In a subgroup analysis of only radiographic axSpA, uveitis, the ASDAS, and the CTSS were associated with total facet joint ankylosis. In axSpA, ankylosed facet joints are prevalent, particularly in the thoracic segment. The ankylosed facet joint score of the entire spine is substantially associated with a history of uveitis, ASDAS, sacroiliitis, and syndesmophyte.

Source: jrheum.org/content/50/6/763