Aim: Is there a need of reduction control with MRI after closed reduction of unstable hips in children with CDH ? Methods: So far 88 children with unstable hip joints received a hip plaster of paris after closed reduction. The x-ray examination of the hip was followed by an MRI of the presumed reduced hip. The MRI examination was performed under sedation of the children with choralhydrat. Results: Out of the 88 hip joints 6 were thought to be in right position after x-ray examination but the MRI showed an unsatisfactory reduction. After a second attempt to reduce the hip joint a follow-up MRI examination was performed showing thereafter a satisfactory position of the hip joint. Conclusions: Due to the high number of missed dislocated hip joints after attempted reduction and x-ray examination we beleave that an MRI of the hip joint is absolute necessary to recognize unsatisfactory reduced unstable hips.