[The radiological study on the open reduction of congenital dislocation of the hip by Ludloff's method. Cases more than 5 years after operation].

Fourty-eight patients with fifty-seven congenitally dislocated hips that had been treated surgically using the Ludloff's technique were followed up for an average of five years from the time of operation. At the final follow up examination the radiological results were good in sixty-five per cent of the hips, fair in twenty-eight per cent and poor in seven per cent. As relating to the age of operation, it was found that good results were seen in eighty-two per cent of the patients below the age of one year, comparing with fourty-eight per cent seen in those patients aged over one year. The incidence of avascular necrosis was fourteen per cent. Although coxa magna was noted in seventy-nine per cent of the hips, there has been a low incidence of coxa magna in those hips in which the ligamentum teres were preserved during operation. About one third of the congenitally dislocated hips in this study required salvage operation after open reduction. In order to find out a reference which would be available in predicting the prognosis of open reduction, a retrospective study of X-ray findings was made. The author found that the prognosis was favorable in those hips which had the CE angle over ten degrees at the time when the brace was removed, whereas a majority of the hips in which the CE angle were below zero needed salvage operation. It was also found that the prognosis of open reduction was good in those patients who had the capital-teardrop distance shorter than ten milimeters and the acetabular head index over sixty per cent at the age of three to four years.