Researchers of a study aimed to determine the prevalence of facet joint ankylosis in axial spondyloarthritis (axSpA) using low-dose computed tomography (LDCT) and identify factors associated with this condition, examining LDCT images of the entire spine from 161 patients with axSpA. They assigned scores ranging from 0 to 46 to quantify the degree of ankylosis. Additionally, they assessed structural damage to the vertebral body using the CT Syndesmophyte Score (CTSS).

The results showed that nearly half of the patients (49% and 43% according to two different readers) had at least one ankylosed facet joint. Thoracic spine involvement was the most common. The average facet joint ankylosis score for the entire spine was 6.6 for one reader and 4.2 for the other. The ankylosis score exhibited a positive correlation with the Ankylosing Spondylitis Disease Activity Score and CTSS. Researchers concluded facet joint ankylosis is prevalent in axSpA, particularly in the thoracic segment. The severity of facet joint ankylosis across the entire spine is significantly associated with a history of uveitis, ASDAS, sacroiliitis, and the syndesmophyte score.

Reference: Lee BW, Jung JY, Kim MY, Hong YS, Park SH, Kang KY. Prevalence and Associated Factors of Facet Joint Ankylosis in Patients With Axial Spondyloarthritis. J Rheumatol. 2023 Jun;50(6):763-768. doi: 10.3899/jrheum.220749.