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Reliability of plain radiographic parameters for developmental dysplasia of the hip in children
Vidyadhar V Upasani1, James D Bomar, Gaurav Parikh
1Department of Orthopedics, University of California, 200 West Arbor Drive, San Diego, CA 92103 USA.
Insights
Reliability of hip dysplasia measurements in children varies. Femoral neck-shaft angle is most reproducible, while center-edge angle and acetabular index show moderate to high agreement.
Area of Science:
- Pediatric Orthopedics
- Radiographic Imaging Analysis
- Developmental Dysplasia of the Hip
Background:
- Limited data exists on the reliability of key radiographic parameters in pediatric hip dysplasia.
- Assessing the reliability of femoral neck-shaft angle (NSA), center-edge angle (CEA), and acetabular index (AI) is crucial for clinical practice.
Purpose of the Study:
- To evaluate the intra- and inter-observer reliability of NSA, CEA, and AI measurements in young children with developmental dysplasia of the hip (DDH).
- To determine if these parameters can be reliably used by practitioners for diagnosing and monitoring DDH.
Main Methods:
- Review of 50 radiographs from 21 children diagnosed with DDH.
- Analysis performed by three independent observers across two separate time periods.
- Assessment of intra- and inter-observer reliability for NSA, CEA, and AI measurements.
Main Results:
- High agreement observed for NSA measurements across observers and time points.
- Moderate to high agreement found for CEA and AI measurements, with improvements noted at the second time period.
- Individual observer reliability for NSA, CEA, and AI generally showed very high to high agreement over time.
Conclusions:
- Measuring 3D pelvic morphology on 2D frontal radiographs presents challenges in young children.
- Reliability of hip dysplasia parameters like NSA, CEA, and AI can be variable, particularly before ossification of key landmarks.
- While NSA shows strong reliability, CEA and AI require careful interpretation due to moderate agreement.
Introduction:
Few studies have evaluated the reliability and reproducibility of the femoral neck-shaft angle (NSA), center-edge angle (CEA), and acetabular index (AI) in young children with developmental dysplasia of the hip (DDH). We wanted to determine whether these parameters could be used reliably by practitioners.
Methods:
Fifty radiographs from 21 children with DDH were reviewed. Analysis was performed by three observers, at two time periods. The intra- and inter-observer reliability for each measure was assessed.
Results:
At time period one, we noted a "high" level of agreement between observers when measuring the NSA, a "low" level when measuring the CEA, and a "moderate" level when measuring the AI. At time period two, we noted a "very high" level of agreement between observers when measuring the NSA and a "high" level when measuring the CEA and AI. When comparing the measurements of observer 1 at the two different time periods, we noted nearly "very high" agreement when measuring the NSA, a "moderate" agreement when measuring the CEA, and a "high" agreement for the AI. In comparing the measurements of observer 2, we noted "very high" agreement for the NSA and "high" agreement for the CEA and AI. In comparing the measurements for observer 3, we noted nearly "very high" agreement for the NSA, nearly "high" agreement for the CEA, and "high" agreement for the AI.
Conclusion:
It is difficult to reliably measure three-dimensional pelvic morphology on a frontal plane radiograph, especially when important pelvic landmarks have yet to ossify.
