Several measurements are used to evaluate hip dysplasia in hip ultrasound of children. Despite having being used since the 1980s, reliability studies have failed to find acceptable reliaiblity values for the gold standard ultrasound methods. This study will evaluate three ultrasound measurement methodologies in a high quality controlled setting, to investigate the best achieveable reliability and agreement of the investigated measurements used in hip dysplasia diagnostics.
In DDH diagnostics, measurements of acetabular alpha angles and femoral head coverages (FHC), developed by Graf and Harcke/Terjesen respectively, have been gold standard since the 1980s. Despite their widespread use, the reliability of these measurements has been questioned due to the relative complexity of acquiring the necessary corIDrect frontal 2D plane or "standard plane". In the only meta-analysis of the reliability of ultrasound (US) metrics in dysplasia, the interrater reliability of the alpha angles was mediocre while the reliability of the FHC was poor. Critics of these findings however argue that the low reliability reported in studies are due to misinterpretation and misapplication of the Graf method. The pubo-femoral distance (PFD) was proposed in 2013 as a new measurement for assessing DDH, while the reliability is reportedly higher than the gold standard US methods, it has never been directly compared to these. This study aims to evaluate the inter- and intrarater reliability of Graf's alpha and beta angles, the FHC and PFD in children referred for hip US in a selective ultrasound screening program for DDH.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
74
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Aarhus University Hospital
Aarhus, Denmark
Reliability and agreement in Alpha/Beta angles, Femoral head coverage and Pubo-femoral distance
For all included ultrasound measurement methods the following will be reported: Inter- and intrarater reliability will be evaluated using the intraclass correlation coefficient (ICC) and interpreted with ICC values between 0-0.5, 0.5-0.75, 0.75-0.9 and above 0.9 indicating poor, moderate, good and excellent reliability respectively. Agreement will be evaluated using Bland-Altman plots (to check for systematic bias) and mean absolute measurement differences between raters.
Time frame: Ultrasound measurements collected during the ultrasound examination by both radiologists
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