Magnetic resonance imaging findings in the sternoclavicular joint in juvenile idiopathic arthritis and comparison with clinical examination.

Objective: The sternoclavicular joint (SCJ), an important link between the appendicular and axial skeleton, though involved in 41% of rheumatoid arthritis patients, has not been studied in juvenile idiopathic arthritis (JIA). Hence, this cross-sectional study was done to delineate the magnetic resonance imaging (MRI) findings in SCJ in JIA and compare with the clinical examination to diagnose SCJ arthritis.

Methods: Of the 116 JIA patients attending the pediatric rheumatology clinic, twenty-one patients (42 SC joints) were evaluated by 1.5 T MRI using the four components of early and late inflammatory changes-synovial hypertrophy, bone marrow edema (BME), cartilage lesions, and bone erosions. Results were compared with clinical assessment of SCJ arthritis.

Results: Of the 42 SCJ evaluated (21/116 patients), MRI changes were seen in 27 SCJs (15 patients, 12.9% of 116 JIA patients). Early MRI changes were seen in 60% of joints found normal on clinical examination, with as much as 1/4th of them revealing late destructive changes. Synovial hypertrophy, BME, cartilage lesions, and bone erosions were seen in 5, 15, 4, and 10 patients, respectively. Sensitivity and specificity of clinical examinations to evaluate SC joint involvement were 55.5% and 53.3%, respectively.

Conclusion: MRI evaluation of the SCJ in JIA revealed findings in 15/21 enrolled patients. BME, bone erosions, synovial hypertrophy, and cartilage lesions were seen in 15, 10, 5, and 4 enrolled patients, respectively. Clinical examination was found to be neither sensitive nor specific. Key Points • MRI could delineate both early and late inflammatory changes in SCJ in JIA. BME, bone erosions, synovial hypertrophy, and cartilage lesions were seen in 15, 10, 5, and 4 enrolled patients, respectively. • The frequency of SC joint involvement in JIA was at least 12.9% of patients in our study. • Clinical examination for evaluating SC joint arthritis has low sensitivity (55.5%) and specificity (53.3%).