Exploration of femoral head coverage in screening developmental dysplasia of the hip in infants
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To investigate the relationship of femoral head coverage (FHC) with Graf’s classification for diagnosis of developmental dysplasia of the hip (DDH) and its role in evaluating hip stability.
A total of 4222 hips were screened ultrasonographically with Graf’s and Harcke’s methods. The stability of hips was analyzed using the difference between FHCs at neutral and flexion positions (FHC-D).
(1) For the non-dislocated hips, the mean value of FHC at the neutral position was 59.4%, which was significantly greater than 55.0% of FHC at the flexion position (p < 0.001). (2) FHC at the neutral position corresponding to Graf I, IIa/b, IIc, D, III, and IV was 63.0 ± 4.7%, 57.0 ± 5.2%, 49.5 ± 5.5%, 37.7 ± 3.7%, 30.2 ± 12.7%, and 7.4 ± 11.9%, respectively, and that at the flexion position was 59.0 ± 4.4%, 50.7 ± 9.4%, 35.2 ± 5.2%, 30.8 ± 1.3%, 23.4 ± 10.7%, and 4.7 ± 9.9%, respectively, showing a statistically significant difference between the two positions. (3) The AUC of FHC-D in evaluating the stability of hips was 0.972. When the threshold was 8.5%, the sensitivity, specificity, and accuracy of FHC-D in detecting hip instability were 89.0%, 93.0%, and 93.9%, respectively.
FHC can be used as a reference indicator for DDH classification. FHC at different positions corresponds to different reference values, and FHC-D can be used as a quantitative indicator for assessment of hip stability.
KeywordsDevelopmental dysplasia of the hip Ultrasonography Femoral head coverage Hip stability
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1964 and later versions.
Informed consent was obtained from all patients for being included in the study.
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