Temporomandibular Internal Derangements Denote Activity of Axial Spondyloarthritis.

Objectives: The group of spondyloarthritis (SpA) disorders shares common clinical manifestations, including internal derangement (ID) of temporomandibular joint (TMJ). This study aimed to investigate SpA activity in patients with ID of TMJ.

Materials and methods: We assessed 200 patients with neck pain using the Assessment of Spondyloarthritis International Society (ASAS) criteria. TMJ was examined using Diagnostic Criteria for Temporomandibular Disorders (DC/TMD protocol). Patients with SpA were divided into three groups: symptomatic ID of TMJ, asymptomatic ID of TMJ, or healthy TMJ (controls). Activity of SpA was evaluated using the Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Disease Activity Index in Psoriatic Arthritis (DAPSA), patients' self-estimated SpA activity, difficulties in performing daily activities, pain intensity (visual analogue scale) and laboratory parameters.

Results: Patients with symptomatic and asymptomatic ID showed statistically significantly increased ASDAS, anti-streptolysin titer, patients' self-estimated axial pain and activity of SpA, and decreased hematocrit than the control. Patients with symptomatic ID also had statistically significant earlier onset of SpA, along with increased BASDAI and DAPSA, total body pain, difficulties in performing daily activities, platelet count, and serum alpha-amylase but lower hemoglobin concentration than controls. Patients with asymptomatic ID had higher frequencies of exacerbated axial SpA and sacroiliac joint ankylosis compared to the control.

Conclusion: All patients with SpA and ID showed increased axial disease activity.