Ultrasonography on developmental dislocation of the hip in infants of different months and the correlation analysis of each parameter index

Abstract

Objective To discuss the changes of correlative ultrasonic parameter index of normal hips and abnormal hips with developmental dislocation of the hip (DDH) in infants of different months in order to provide objective information for the diagnosis. Methods Three-hundred and seventy-eight normal hips and 244 hips with DDH among 622 hips of 311 infants were detected by ultrasonography(US). The morphology and structure information of hips were observed, and the values of ultrasonic parameter index,including angle α,angle 3, acetabular index( AI), femoral head percentage of cover(FHC) of normal hips and abnormal hips were measured. The values of each parameter index were collected by being divided into different groups (3 months a group) ,then the correlation was analyzed. Results Morphology and structure,position relation between femoral head and acetabulum of the hips were demonstrated by US. Normal or abnormal hips,the degrees of abnormal hips and the types of hips could be judged according to the findingsof US. Analysis of values of parameter index of normal hips:①There was significantly statistical significance in the values of ultrasonic parameter index, such as angle α, angle β, AI, FHC of normal hip between the groups of different age (P＜0.01). ②There was correlation between the age and the values of each parameter index, among which angle α, FHC had positive correlations with age ( r = 0. 537, 0. 554,respectively ) while angle β and Al negative correlations ( r = -0. 465, -0.424, respectively ). ③There was correlation between the values of different parameter index. Both angle β and AI had negative correlation with angle α,among which the latter correlation was closely ( r = - 0. 794). No statistical significance was found between the ultrasonic values of each group under different ages of different type abnormal hips( P ＞0.05) ,but closely negative correlations still existed between angle α and AI. Conclusions US can be viewed as an early definite and a screening method of diagnosing DDH.For older infants (above 6 months) it will be more accurate to analyze the ultrasonic parameter index together with the age of infants. Key words: Ultrasonography; Hip joint; Hip dislocation; Infants