Background/Purpose: TMJ involvement has been reported in all subsets of JIA. The prevalence of radiographic changes of TMJs varies from 30% to 65%, and 50-80% of children with JIA will have evidence of TMJ arthritis by MRI and by sonographic exam (SE) (effusions, synovial enhancement, condylar flattening and/or erosions, thickness of masseter muscle) before evidence of X-ray damage. At disease onset local injections with steroids or/and anti-TNF alpha blockers are recommended, but when joint damage is late recognized orthopedic treatment is suggested. Our aim is to evaluate the efficacy and safety of orthopedic treatment in a cohort of adolescents and young adults with JIA.

Methods: Our study population included 102 consecutive pts (76 F and 26 M, mean age 14.5±4.4 yrs), mean age at JIA onset 7.9±5 yrs, mean disease duration at first orthodontic evaluation 7.7±5.2 yrs, fulfilling the ILAR criteria for JIA, all treated at Transition clinic of  Rheumatology Department between December 2009 and December 2011. Out of 102 pts, 53 had oligo (O-JIA), 34 polyarticular (P-JIA), 4 systemic (S-JIA), 11 enthesitis-related arthritis (ERA-JIA) onsets. The diagnosis of TMJ disease was performed on the presence of at least one Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) diagnosis. The anamnestic and functional data were collected in a medical record used by orthodontists of University of Pavia, Italy. 69/102 pts (68 %) showed recurrent pain localized in the temporomandibular area, crepitation, and jaw stiffness or fatigue. All TMJs were examined by panoramic X-ray, teleradiography with latero-lateral and anteror-posterior view, and by SE by Esaote MyLAB 70 (Genoa Italy linear probe 8-13 MHz). At first orthodontic evaluation 75 pts showed dento-skeletal malocclusions leading to a Class II caused by skeletal retrognathia, post-mandibular rotation, lower height of the mandibular body  and ramus that can determine asymmetries in the frontal and/or in the sagittal plane.

Results: 51 pts (50%) undergone to orthopedic therapy with an activator order to help mandibular growth. After orthopedic therapy these pts had worn a bite. 31 pts (30.3%) wore a bite without orthopedic therapy. 20 pts (20%) did not receive any treatment. After two years from first orthodontic evaluation 58/ 75 pts (77.3%) showed improvement in occlusion, masticatory function and cranio-facial morphology. In 69 pts the thickness of masseter muscle, detected by SE after therapy, was similar on left and right side (mean value 7.6 mm) at rest and after contraction (p<0.001). In all pts SE showed bone remodeling of the condyle head, and in 62/102 (61%) pts monolateral erosions were present.

Conclusion: Our data confirm that early diagnosis and treatment should prevent the severe  and often intractable damage in TMJ of JIA patients. The irreversible damage as micrognathia, aberrations in mandibulofacial development, and facial asymmetry may compromise the growth cartilage and rapidly progress into bone erosion of the condylar head. In our study, the results suggest that in case of delayed diagnosis and severe destruction of TMJs, an orthopedic  treatment may be helpful in reducing the progression of  bone injury.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/orthopaedic-treatment-of-temporomandibular-joint-tmj-damage-in-adolescents-with-juvenile-idiopathic-arthritis-jia-longitudinal-evaluation/