Synovitis in legg-calvé-perthes disease

Abstract

Purpose: to evaluate, by means of MR imaging, the degree and persistence of synovitis in the hip joint in Legg-Calvé-Perthes disease and to correlate the degree of synovitis with the degree of epiphyseal necrosis

Material and Methods: A total of 170 MR images in 72 patients (84 hips) were examined. the T2-weighted MR images were taken in the coronal plane in order to evaluate the degree of synovitis in the hip joint

Results: MR revealed synovitis in all cases in the early phase of the disease. in Catterall group II, synovitis was discreet to moderate for up to 6 months after diagnosis. Hips with more severe necrosis, Catterall groups III and IV, had moderate or intense degrees of synovitis. There was a correlation between the degree of synovitis and the lateral pillar classification according to HERRING et al. Also, there was a good correlation between the extent of signal changes in the epiphysis on MR imaging and the degree of synovitis. There was no difference when signal changes were evaluated on T1- or T2-weighted images. Signs of synovitis could be seen for up to 30 months after diagnosis in Catterall group I hips, and in Catterall groups II and III for up to 36 months, and in 2 cases even longer. Some Catterall group IV hips had discreet or mild synovitis for 60 months or more, after diagnosis

Conclusion: the degree of synovitis on MR imaging correlates to the extent of epiphyseal necrosis seen on radiographs or MR imaging as well as to the lateral pillar classification, i.e. to a poor clinical outcome. in Catterall group IV hips, synovitis can even persist for up to 60 months after diagnosis