Ultrasonographic Assessment of the Proximal Femoral Ossification Center in Children Under 1 Year

Abstract

Background. Developmental disorders of the secondary ossification center (SOC) of the proximal femoral epiphysis can be a marker of some childhood diseases that require timely diagnosis and treatment.
 The study aimed to assess the capabilities of ultrasonography in the diagnosis of ossification processes of the proximal femoral epiphysis.
 Material and Methods. The study is based on the results of a survey of 524 children aged 2 weeks to 1 year with normal hip joints, including 259 boys and 265 girls. All patients underwent ultrasound examination of the hip joints according to the method of R. Graf in a standard coronary section. In older children, to eliminate errors in measuring the size of the SOC, an additional cross-section was used.
 Results. The SOC was detected in isolated cases in boys aged up to 3 months and girls up to 2 months. At age 3 months, the SOC was visualized in 45% of girls and 5% of boys. By age 5 months, 81% of girls had a SOC compared with 46% of boys. By 7 months, SOC was determined in more than 90% of cases of both groups. Thus, girls showed an earlier formation of the SOC than boys. The SOC was located in the center of the femoral head in 82% of cases, lateral in 14%, and medial in 4%. In 95% of the examined children, SOC development occurred symmetrically in both joints. In addition, discrepancies were revealed with simultaneous ultrasonography and X-ray of the hip joints since the SOC becomes visible earlier during ultrasonography.
 Conclusion. Sonography is a highly informative method for determining the ossification processes of the proximal femur. Knowledge of the normal sonographic appearance of the femoral head SOC by age and sex will help clinicians diagnose and treat hip disorders.