Transinguinal sonographic determination of the position of the femoral head after reposition and follow-up in a spica cast

Abstract

Background Transinguinal sonography can be used to demonstrate the position of the femoral head after reduction of a dislocated hip. Objective To determine whether transinguinal sonography can replace radiography and CT in the follow-up after reduction of a hip dislocation? Materials and methods Thirty-three children with 39 dislocated hips were followed up with sonography after reduction and immobilization in a spica cast. In cases of an abnormal position a CTscanwas advised.A pelvic radiograph at the end of treatment served as an indicator that no dislocations were missed during the previous sonographic examinations. Results The repositioned hips were examined on 138 occasions. Twenty-four examinations were abnormal and CT scanning was performed on 11 occasions. In four children additional CT was done because a recurrent dislocation was suspected or because sonography was difficult to perform. No dislocations were demonstrated. In five children a recurrent dislocation was suspected, on one ormore occasions. In all but one child a CT scan was performed that confirmed the dislocation. Conclusion Transinguinal sonography is well-suited to demonstrate a normal position of the femoral head in a spica cast. Transinguinal sonography decreases the number of radiographs and CT scans and reduces the exposure to ionizing radiation. © The Author(s) 2010.