To identify the physical findings associated with active temporomandibular joint (TMJ) inflammation (ie, synovitis) in children with juvenile idiopathic arthritis (JIA).
This was a retrospective study of children with JIA evaluated at Boston Children's Hospital. The patients were included if they had a confirmed diagnosis of JIA and had undergone a TMJ magnetic resonance imaging (MRI) study with contrast. Medical records and imaging studies were reviewed to document the demographic, physical (ie, facial asymmetry, joint noises, maximal incisal opening, deviation on opening, occlusal cant), and MRI findings. The outcome variable was TMJ synovitis on the MRI study. Descriptive and bivariate statistics were computed. Multiple regression models were used to identify associations (P ≤ .05, significance).
A total of 51 patients with JIA were evaluated during the study period. Of these, 43 patients (33 girls) with a mean age of 11.4 years met the inclusion criteria. MRI demonstrated TMJ synovitis in 27 patients. The age-adjusted limited maximal incisal opening (MIO) and deviation on opening were the only physical findings significantly associated with synovitis on MRI (P = .003 and P = .043, respectively). Using these parameters as predictors of synovitis, a limited MIO and deviation on opening had a high specificity (86% and 94%, respectively). Patients with a limited MIO were 6.7 times more likely to have synovitis than those with a normal MIO. All patients with a limited MIO and deviation on opening had TMJ synovitis on the MRI scan.
The results of this study indicate that, in children with JIA, limited MIO and deviation on opening can be used to predict the presence of TMJ synovitis. Documentation of these parameters should be an essential part of the clinical examination and longitudinal follow-up of children with JIA.