Role of MRI in evaluation of hip joint involvement in juvenile idiopathic arthritis

ABSTRACT

Evaluate the role of MRI in diagnosing hip arthritis and correlating it with clinical and laboratory assessments in juvenile idiopathic arthritis [JIA]. The study included 30 patients with JIA with mean age of 13.5 +/- 4.5. Disease activity was evaluated by DAS28 score, physician's global assessment [PGA-VAS], patient's global assessment [VASglobal] and the assessment of functional ability by [CHAQ]. Hip joint evaluation was assessed by hip pain on movement and the degree of limitation of motion [score 0-3]. Plain radiography and MRI of the hip joint were performed for all patients. MRI score was done. MRI of hips was abnormal in 12 [40%] of all patients 2/8 [25%] of oligoarticular group, 4/13 [30.8%] of polyarticular group, 5/7 [71.4%] of systemic onset group and 1/2[50%] of enthesitis related group. Comparing mean values of MR scores of the four clinical subsets showed significant difference [p < 0.001]. Patients with active disease showed higher MR scores [3.7 +/- 1.5] than those with inactive disease [2.1 +/- .9] [p < 0.002]. Presence of effusion and gadolinium enhancement were significantly higher in active hips [p < 0.01 and p < 0.001 respectively]. VAS-PGA and ESR were significantly correlated with MRI score [p < 0.02 and <0.05 respectively]. MRI of the hip plays an important role in the study of patients with JIA as it reveals early joint involvement and evaluates the extent of joint disease. This permits intervention at an appropriate time with suitable treatment. Clinical and laboratory findings are inadequate diagnostic tools for the assessment of hip arthritis when comparing with MRI