Legg-Calve-Perthes disease: MR imaging evaluation during manual positioning of the hip - Comparison with conventional arthrography

PURPOSE: To evaluate the use of magnetic resonance (MR) imaging during manu al positioning of the hip, or multipositional MR imaging, in an open-magnet configuration to study femoral head containment, articular congruency, and femoral head deformity in Legg-Calve-Perthes disease. MATERIALS AND METHODS: In 12 children with advanced Legg-Calve-Perthes dise ase, multipositional MR imaging and conventional arthrography were compared in the assessment of containment, femoroacetabular congruency, and femoral head deformity. Images of the hips in several positions were compared subj ectively and objectively. RESULTS: MR imaging correlated well with arthrography for overall subjectiv e assessment of severity of disease (r = 0.71, P = .01), with good interobs erver agreement (kappa = 0.65, P < .001). MR images demonstrated all cases of hinge abduction shown arthrographically. However, MR imaging failed to d epict one case of femoral head flattening. MR imaging correlated well with arthrography in the objective evaluation of joint fluid and lateral subluxa tion (r = 0.80, P < .01). MR imaging correlated poorly with arthrography in the measurement of sphericity of the femoral head. CONCLUSION: Multipositional MR imaging with an open-magnet configuration an d congruency of the articular surfaces of the hip. In the evaluation of def ormity, it performed less well.