Temporomandibular joint involvement in psoriatic arthritis: a prospective clinical and ultrasonographic study

OBJECTIVES: To evaluate the prevalence of temporomandibular disorders (TMD) in a monocentric cohort of patients affected by psoriatic arthritis (PsA), and to investigate the accuracy of temporomandibular joint (TMJ) ultrasound (US) compared with clinical evaluation and clinimetric composite index in assessing TMJ involvement. METHODS: We conducted a prospective cohort study of patients diagnosed with PsA who underwent at least one TMJ US examination and maxillofacial surgeon's evaluation between 2018 and 2021. The rheumatology physician's interpretation of each TMJ US exam (presence/absence of TMD) was compared with psoriatic arthritis disease activity indexes and maxillofacial surgeon's clinical judgement (presence/absence of TMD signs and/or symptoms). RESULTS: 142 psoriatic arthritis patients were included. 111 patients were totally asymptomatic for TMD, but 58.5% of them already showed TMJ US changes; moreover, 103 patients passed the maxillofacial surgeon's examination in the absence of any relevant findings but again, of these, 55.3% already presented US signs of TMD. Univariate analysis of subgroups with and without TMJ synovitis and with and without active power Doppler signal showed a significant prevalence of peripheral enthesitic involvement in patients affected by TMD (95.7% vs. 4.3%, p=0.001; and 72.2% vs. 27.3%, p=0.007, respectively). Multivariate regression analysis confirmed the results (p=0.01 and p=0.013, respectively). CONCLUSIONS: Peripheral enthesitic involvement may represent a potential risk factor for the development of TMJ synovitis in PsA patients. Since TMD often develops asymptomatically, TMJ US may detect early signs of TMD, ensuring precocious and adequate management.