Mapping the evidence on ultrasonography for temporomandibular joint evaluation in rheumatoid arthritis: a scoping review

To perform a scoping review on the application of ultrasound (US) for identifying temporomandibular joint (TMJ) alterations in patients with rheumatoid arthritis (RA). An electronic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Embase, and gray literature sources until October 2025, with no language or publication date restrictions. Observational studies and clinical trials evaluating TMJ alterations using US in RA patients were included. Data were collected on study design, sample characteristics, RA-related clinical parameters, TMJ clinical findings, US techniques, and main imaging results. Initially, a total of 88 records were retrieved. After applying theeligibility criteria, five studies met the inclusion criteria. One hundred and fifty-four patients with RA were evaluated. Most participants were women and had moderate-to-high disease activity. Among the studies reporting age specifically for the RA subgroup, mean ages ranged from 45.4 to 53 years. The US consistently identified joint effusion, synovial thickening, and disc alterations. Only one diagnostic accuracy study reported that US demonstrated 92.4% sensitivity and 90.3% specificity for detecting joint effusion compared with magnetic resonance imaging (MRI). Associations between US findings and clinical indices (DAS28, HAQ) and pain were observed, although inconsistently. Methodological heterogeneity, small sample sizes, and operator dependence were the main limitations. US is a practical, non-invasive, and affordable adjunctive initial imaging examination for detecting inflammatory TMJ changes in RA. However, it should complement rather than replace MRI, particularly for structural assessment. Future research should prioritize standardized protocols, larger longitudinal cohorts, and integration with clinical and serological data.