High-resolution ultrasound in the early detection and follow-up of TMJ symptoms and signs in Juvenile Idiopathic Arthritis

Aim: Temporomandibular joint (TMJ) arthritis is common in children with juvenile idiopathic arthritis (JIA) but often clinically asymptomatic. Clinical signs or symptoms of TMJ dysfunction are not always predictors of bony destruction. The aim of the study is to evaluate the usefulness of ultrasound (US) in suspecting condylar bone alterations in young pts with JIA Materials and Methods: 70 patients have been assessed by ultrasonographic exams. US offers specific advantages because it is non-invasive, does not require sedation or general anesthesia (which facilitates examinations for follow-up), is quickly accessible bedside, and is easy to combine with clinical assessment (interactivity). Agitation of the patient is rarely a problem, as MRI and multiple locations can be assessed during a single session. Furthermore, modern high-frequency US transducers used by experienced US examiners can provide unsurpassed resolution of the superficial musculoskeletal structures. Results: Were detected morphological alterations and positions of mandibular condyles in the glenoid fossa, condylar synovitis, disc displacement and joint effusion. 24 out of 70 patients (34%) had normal US appearance on both side. Irregularities of the bony surface were found in 67 joints (90%) whereas capsular thickness in 49 ones (30%). Vascular signal was increased in 5 joints and always associated with other abnormalities, the same as disk dislocation (3 joints). Translational asymmetry between open and closed mouth position was found in 11 joints and could not be evaluated just 3 patients, the youngest ones (2 - 3 years). Conclusions: Ultrasonography can be suggested for the evaluation of TMJ disorders, with particular accuracy in the detection of disc displacement and joint effusion. Limitations are especially related to the scarce accessibility of the medial part of the TMJ structures, and the need for trained and calibrated operators. High-resolution ultrasonography is a valuable tool through in particular situations: (i) when MRI examination is not available; (ii) when children are afraid of MRI examination; (iii) in more advanced stages of JIA.