Clinical Findings Associated with Temporomandibular Joint Involvement in Children with Juvenile Idiopathic Arthritis
STATEMENT OF THE PROBLEM: The gold standard for diagnosis of temporomandibular joint (TMJ) synovitis in children with Juvenile Idiopathic Arthritis (JIA) is magnetic resonance imaging (MRI). 1 MRIs can be costly, time consuming and may require general anesthesia. Therefore, it would be beneficial to recognize physical findings that consistently reflect the presence of TMJ synovitis. The purpose of this study was to identify clinical findings associated with synovitis in pediatric JIA patients.
METHODS OF DATA ANALYSIS: The sample included children with JIA, according to International League of Associations for Rheumatology, who were evaluated by Oral and Maxillofacial Surgery (OMFS) at ChildrenÕs Hospital Boston and who had an MRI with contrast of TMJs. 2 Data collected included: (1) demographics (gender, age), (2) clinical examination (jaw pain, facial asymmetry, joint noises, maximal incisal opening (MIO), lateral excursions, deviation on mouth opening, maxillary occlusal cant), and (3) MRI findings (presence or absence of synovitis). Cases were defined as patients with JIA and TMJ synovitis on MRI; controls were patients with JIA without synovitis. Statistical analysis was used to identify associations between clinical findings and TMJ synovitis. P-value<0.05 was considered significant.
RESULTS: There were 43 subjects (33 females) with a mean age of 11.4 years (range 3-19 years) who met inclusion criteria. Of these, 27 cases (63%) had MRI findings consistent with TMJ synovitis. Sixteen patients (37%) did not have synovitis. Frequency of abnormal findings in patients with synovitis was: limited MIO (N=23, 85%), facial asymmetry (N=10, 37%), deviation on mouth opening, (N=9, 33%), jaw pain (N=8, 30%), joint noises (N=5, 18.5%), and maxillary cant (N=5, 18.5%). In patients without synovitis the frequencies were: limited MIO (N=6, 37.5%), facial asymmetry (N=5, 31%), pain (N=5, 31%), joint noises (N=4, 25%), maxillary cant (N=2, 12.5%), and deviation on mouth opening, (N=1, 6%).
Of all predictor variables tested with univariate analysis, limited MIO and deviation on opening were significantly associated with synovitis on MRI (p=0.004 and p=0.007, respectively). Limited MIO had a sensitivity of 0.85, specificity of 0.86, and deviation on opening had a sensitivity of 0.10 and specificity of 0.94. In a multiple regression model (controlling for age, gender, deviation), subjects with limited MIO were 6.7x more likely to have synovitis (95% CI 1.44-31.20, p=0.02). Among subjects with limited MIO, deviation on opening confirms the presence of synovitis (positive predictive value = 1.00 and negative predictive value = 0.46).
DISCUSSION: Results of this study demonstrate that among children with JIA, The combination of limited MIO and deviation on opening are indicative of TMJ synovitis. Measurement of MIO and deviation on opening should be an essential part of clinical examination and longitudinal follow up of children with JIA.
REFERENCES:
1. Arabshahi B, Cron RQ. Temporomandibular joint arthritis in juvenile idiopathic arthritis: the forgotten joint. Curr Opin Rheumatol. 2006 Sep;18(5):490-5.
2. Abramowicz S, Cheon JE, Kim S, Bacic J, Lee EY. Magnetic resonance imaging of temporomandibular joints in children with arthritis. J Oral Maxillofac Surg. 2011Sep;69(9):2321-8