[Ultrasound screening for hip dysplasia in newborns and treatment with Frejka pillow]

The prevailing strategy concerning ultrasound screening for DDH in newborns in Norway does not intercept all who should be treated. In recent years typical rates for hospital treatment of late hip dislocations in newborn have been 15-20 cases. By universal ultrasound examination, 10-20 % of the newborns present with "physiological immature" hips. By this we mean hips with subnormal ultrasound values that will normalise in the course of the neonatal period. An agreed basis of defined and standardised criteria in order to diagnose and treat physiological immature hips is required. We hope tat this study will contribute to the final solution to these questions.

Over the period 1 February 1998 through 2002 we had 2466 alive newborns at our hospital. 26 were directly transferred to another hospital, 130 were left out because of limited skills or inadequate training in ultrasound among temporary staff. The hips have been graduated morphologically in accordance with Graf's alpha angle. All newborns have been investigated by ultrasound and clinical examination with Ortolani/Barlow test 1-3 day after birth. Those with diagnosed dysplasia (alpha < 50 masculine) and those with positive clinic and physiological immature hip were immediately treated with Frejka pillow. Those with negative clinic and physiological immature hip were revaluated after 4 weeks by ultrasound, and those still immature were given Frejka pillow. Duration of pillow treatment was 4 months, followed by further clinically and radiological surveillance. All infants given the pillow treatment were clinically examined 2-3 months after they were able to walk without support, and again 1-5 years later radiologically.

Of the newborn, 31 (1.3%) had a positive Ortolani/Barlow test. Among them, 7 had dysplasia, 20 immature hip; 4 were normal. Among the 2275 infants with normal clinic, 9 had dysplasia and 232 (10.9%) had at least one physiological immature hip. After 4 weeks, 26 still had immature hip by ultrasound evaluation. A total of 62 infants (2.7%) were treated with Frejka pillow. At the "walk alone" control and the radiological control 1-5 years later, there were no pathological findings, specially no sign of aseptic necrosis. In the total material we had 2 girls with late subluxations, detected at the age of 8 and 10 months. Both had normal clinic with an ultrasound immature hip at birth. They should have been followed up, but were missed, for uncertain reasons. Both attained normal hips after treatment.

Our study of universal ultrasound screening for DDH of the hips in newborns shows that 1 % of the infants born with normal hips clinically still have physiological immature hips at the age of 4 weeks. Taking those into account as potentially dysplastic, it gives an overall treatment rate of 2.7%. Today, the only possible way to intercept those physiological immature hips that will not normalise is by universal ultrasound examination. For these children, early treatment with Frejka pillow is effective, without any risk of iatrogenic injury.