Experience with a 3-dimensional sonographic system in infant hip joints

To test the possibilities of 3-dimensional sonography in diagnosing congenital hip dysplasia. Method: 128 infant hip joints were examined by 4 investigators with different levels of experience. The Kretz Combison 530 machine additionally equipped with an automatic 5 MgHz transducer and volume box system was employed. Results: The average time to determine the standard plane was 21 seconds. The single standard deviation for alpha values in the 3-dimensional system was 3.0 degrees, compared to 1.37 degrees in the conventional system. Observer experience was not a crucial factor. Conclusion: The described 3-dimensional system makes it quicker and simpler to determine the standard plane when evaluating infant hips. The higher standard deviation is possibly caused by the obliquity of the ultrasonic beam. Ossification defects on the acetabular roof are better visualized with this approach than with conventional ultrasound or radiological methods. Even though 3-dimensional ultrasound represents a new approach to infant hips, it seems worthy of rapid development.