Reliability of plain x-rays for developmental dysplasia of the hip in children

Reliability of plain x-rays for developmental dysplasia of the hip in children

In the current era there are growing concerns of radiation exposure particularly in the children. In spite of amazing advances in the field of imaging, regular x-rays continue to remain the primary tool of evaluating hip dysplasia in children older than 4-months. MR imaging in this age group needs anesthesia. Radiographic measurements are commonly used to decide treatment and evaluate dysplasia.

Upasani et al conducted a study at Rady Children’s hospital, San Diego to answer the following question:


What is the reliability and reproducibility of the x-ray measurements we use to measure dysplasia in young children?


Fifty radiographs from 21 children with DDH were reviewed. Analysis was performed by three observers, at two time periods.

At time period one, authors noted a “high” level of agreement between observers when measuring the alignment of the femur, but lower reliability for measuring the slope of the socket. The reliability between measurements by the same physician were better than the reliability of measurement between different physicians measuring the same x-ray. However the amount of variability was within the range that allowed reliable decision-making.

Authors concluded that it is difficult to reliably measure three-dimensional pelvic shape on a frontal x-ray, especially when important pelvic landmarks have yet to ossify.


This article outlines the limitations in using regular x-rays as the sole method for management of DDH in infancy and childhood. However, this is the best we have currently.

The International Hip Dysplasia Institute is committed to resolving some of these issues through cooperative research at multiple academic institutions. One of the IHDI centers (San Diego) is currently exploring the use of three-dimensional ultrasound imaging for diagnosis and treatment decision-making of DDH in infancy.


Vidyadhar V. Upasani, James D. Bomar, Gaurav Parikh, Harish Hosalkar. Reliability of plain radiographic parameters for developmental dysplasia of the hip in children. Journal of Children’s Orthopaedics, Online First™, 26 May 2012