Roentgenographic parameters of the normal infant hip

Area of Science:

• Pediatric Orthopedics
• Developmental Biology
• Radiology

Background:

• Understanding typical hip development is crucial for diagnosing developmental dysplasia of the hip (DDH).
• Standard radiographic parameters are used to assess hip joint maturity and stability in infants and young children.

Purpose of the Study:

• To analyze multiple radiographic parameters of hip development in children from 3 to 12 months of age.
• To establish normative data and assess the reliability of various measurements during early childhood hip development.

Main Methods:

• Longitudinal analysis of hip radiographs from 100 children at 3, 6, 9, and 12 months.
• Measurement of acetabular index, H distance, D distance, medial gap, center edge angle, and assessment of secondary ossification centers and Shenton's line.

Main Results:

• Acetabular index and center edge angle showed age-related increases, while H distance remained constant. D distance increased with age.
• Medial gap measurements were highly variable; the acetabular teardrop was inconsistently present.
• Asynchronous appearance of secondary ossification centers did not correlate with abnormal hip development.

Conclusions:

• Key radiographic parameters like acetabular index and center edge angle demonstrate predictable changes during normal hip development.
• Certain measurements, such as medial gap and Shenton's line, exhibit high variability and poor reproducibility in this age group.
• Normal variations in ossification timing do not necessarily indicate future hip abnormalities.