Assessment of Temporomandibular Joint Degeneration in Rheumatoid Arthritis Patients Using Cone-Beam Computed...

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease and often affects the temporomandibular joint (TMJ), causing progressive degenerative alterations that severely affect the quality of life of the patients, their mastication, and their general functional abilities. TMJ has not been adequately studied as a clinical aspect of RA despite the fact that it may occur in the earliest stages of the disease, with a few symptoms, and because no specific surveillance guidelines have been put in place. The timely prevention of degenerative alterations with timely therapeutic responses and the most effective imaging options to holistically evaluate TMJ are a highly debated subject of rheumatological and dental medicine.

Sixty RA patients with the American College of Rheumatology/European League against Rheumatism 2010 classification criteria and 30 age- and sex-matched healthy people without TMJ disorders or systemic inflammatory conditions were enrolled in this cross-sectional control study. TMJ bilateral measures were conducted using standardized cone-beam computed tomography (CBCT) measures to assess the changes in the bone including erosions, osteophytes, cysts in the subchondral area and joint space width (JSW) measurement, and the musculoskeletal ultrasound (MSKUS) examination that measured the soft-tissue pathology of joint effusion, synovial hypertrophy and the associated vascularity, and the erosion of the articular disc. These statistical analyses consisted of independent t-tests when comparing continuous variables, Chi-square when comparing categorical variables, and Cohen's kappa coefficient when measuring inter-observer and intermodality agreement.

RA patients exhibited much more prevalent rates of osseous degenerative alterations than in healthy controls: Cortical erosions (68.3% vs. 10.0%, P < 0.001), osteophytes (45.0% vs. 6.7%, P < 0.001), subchondral cysts (31.7% vs. 3.3% P = 0.002) and significantly smaller mean JSW (1.8 0.5 mm vs. 2.5) similar pathological alterations of the soft tissue were also frequent among the RA cohort: Joint effusion (71.7% vs. 16.7, P = 0.001), active synovitis with Doppler signal (63.3% vs. 13.3, P = 0.001), and anterior displacement of the disc (38.3% vs. 10.0, P = 0.004). CBCT and MSKUS had a high intermodal consensus when it comes to detecting erosion (K = 0.75) and moderate consensus when detecting synovitis (K = 0.62).

CBCT and MSKUS are useful in detecting different but complementary features of TMJ degeneration in RA patients, with the former being the best in revealing the detailed presence of the changes in the surroundings in a more detailed way, and the latter being the best in identifying and characterizing the presence of soft-tissue pathology and active inflammation. The combination of both modalities greatly improves diagnostic accuracy of the whole process of assessment and has more overall joint evaluation, which in turn benefits the evidence-based clinical decision-making and timely management intervention in patients with RA with TMJ involvement.