ASSOCIATIONS BETWEEN CT AND MRI ASSESSMENTS OF THE TEMPOROMANDIBULAR JOINT AND CRANIOFACIAL GROWTH DISTURBANCES: A 27 YEARS FOLLOW-UP OF PATIENTS WITH JUVENILE IDIOPATHIC ARTHRITIS

Background: Craniofacial growth may be disturbed in patients with juvenile idiopathic arthritis (JIA) with temporomandibular joint (TMJ) involvement as the most important etiologic factor. There is no study that addresses the relationship between craniofacial growth and TMJ abnormalities in unselected adult patient with JIA. Objectives: To assess the outcome of TMJ involvement as assessed by CT and MRI in relation to craniofacial morphology in 60 adult patients with JIA. Methods: Sixty (44 females) out of 103 patients participated in a re-examination on average 27 years after baseline (1). Mean age at baseline was 8.6 years (SD 2.9). Craniofacial morphology, size and position of the mandible was assessed in lateral cephalograms, and the TMJ involvement was assessed by CT and MRI. Lateral cephalogram variables of 54 healthy adults were used as controls. The study was approved by the local ethics committee and all patients gave their informed consent. Results: Forty-three (72%) of the 60 adult JIA patients had JIA TMJ involvement at follow-up, mostly (88%) bilaterally. Typically, the mandibular condyle was flat and broad in oblique sagittal plane, the fossa/eminence was flat and wide, and the articular disk was thin or perforated in a normal position, if not absent. Contrast enhancement was low and bone marrow edema almost absent. Thirty (70%) of the 43 patients with TMJ involvement had some form of craniofacial growth disturbance. A number of craniofacial morphology variables were significantly different between patients with bilateral TMJ involvement and those without TMJ involvement. Significant differences were also found between the bilateral TMJ group and the healthy controls. There were no differences in craniofacial morphology variables between the patients without TMJ involvement and the healthy controls. Three patients without TMJ involvement had some form of craniofacial growth disturbances. Micrognathia occurred in 36% of the patients with bilateral TMJ involvement and in 27% in the entire series of patients. Half of the patients without craniofacial growth disturbances had TMJ involvement and of those, more than half had had TMJ involvement since before the age of 12. Conclusion: TMJ involvement is frequent in adult JIA patients and characterized by deformities of the mandibular condyle, articular fossa/eminence, and articular disk, and low inflammatory activity. The majority of patients with TMJ involvement had craniofacial growth disturbances. However, growth disturbances did not always follow involvement of the TMJ, even when affected in early age. References: 1. Stabrun AE, Larheim TA, Höyeraal HM, Rösler M. Reduced mandibular dimensions and asymmetry in juvenile rheumatoid arthritis. Pathogenetic factors. Arthritis Rheum 1988;31:602-11 Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 68, supplement 3, year 2009, page 507Session: Paediatric rheumatology (Poster Presentations )