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Morphometric and ultrasonographic study of the human fetal hip joint during intrauterine development
Beáta Baróti1, Zsuzsanna Pap, Z Pánti
1University of Medicine and Pharmacy of Tirgu Mures, Romania; panti.zsombor@gmail.com.
Insights
Prenatal ultrasound screening for developmental dysplasia of the hip (DDH) reveals that hip joint stability increases as the fetus develops. The Graf method
Area of Science:
- Orthopedics
- Fetal Development
- Medical Imaging
Background:
- Developmental dysplasia of the hip (DDH) is typically screened using ultrasound in newborns.
- Limited research exists on prenatal hip joint development using ultrasound.
- The Graf method's alpha angle is a key metric for hip assessment.
Purpose of the Study:
- To investigate prenatal hip joint development.
- To analyze the evolution of the alpha angle via ultrasound and anatomical dissection.
- To correlate ultrasound findings with fetal hip morphology.
Main Methods:
- Analyzed 31 post-mortem fetal hips using anatomical dissection.
- Performed ultrasound imaging on 25 fetal hips to measure the alpha angle.
- Calculated a secondary angle (α1) using morphometric data and the sine rule to assess femoral head coverage.
Main Results:
- Femoral head, acetabulum diameters, and joint cavity volume increased during fetal development.
- Both measured (α) and calculated (α1) alpha angles decreased as the fetus matured.
- The alpha angle is reliably measurable after 18 weeks of gestation, coinciding with acetabular ossification.
Conclusions:
- Decreasing alpha angles and increasing joint cavity indicate reduced hip stability in early fetal life.
- Findings align with existing literature on perinatal hip joint laxity.
- Accurate alpha angle measurement for DDH screening requires sufficient acetabular ossification, typically after 18 weeks gestation.
Unlabelled:
The main method for the early screening of the developmental dysplasia of the hip (DDH) is the ultrasound imaging. There are several studies about the ultrasound imaging of newborns' hips, but only a few studies include the prenatal period of life. Our aim was to examine the prenatal development of the hip joint through the evolution of the α angle seen on the ultrasound, described in the Graf R method, combined with anatomical dissection.
Materials And Methods:
Thirty-one post-mortem fetal hips were analyzed trough anatomical dissection, in 25 cases trough ultrasound imaging, in which the α angle was measured. Based on the morphometric examination, we applied the sine rule and we calculated the α1 angle, which also represents the coverage of the femoral head.
Results:
Based on the morphometric examination, not only the diameters of the femoral head and of the acetabulum, but also the joint cavity (X) showed an increase during development. Both of the α angles (measured α, calculated α1) showed a decrease as the fetus developed.
Conclusions:
The decrease of the angles (α, α1) and the increase of the joint cavity during development correspond to the findings of the main research papers: the hip joint is less stable in the perinatal life. The α angle can be accurately determined only after the ossification of the acetabulum had started, in our case after the fetus is older than 18 weeks.
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