Background:

In order to avoid sequelae in the development dysplasia of the hip the treatment should be early; The acetabular angle corresponds to the inclination of the roof of the acetabulum. Stanisvljevic indicates that to properly measure the acetabular angle, the hips should be placed in abduction. Question: What is the magnitude of the difference in radiographic measurement of the acetabular angle between the anteroposterior projections of pelvis in neutral position and with abduction of hips?

Methods:

916 radiographic measurements were taken by contrasting the neutral position against those of hip abduction, of patients in our clinic attended between April 1, 2010 and March 31, 2013.

Results:

T tests were performed for means of two matched samples and a hypothetical difference of the mean of 0.0000 was obtained and the Pearson correlation coefficient for right hip was 0.74427531 and for the left 0.73779866. Using a proposed Table of normality of the Acetabular angle according to age, the area was obtained under the curve in a distribution Tgl457 = 0.650 with P = 0.516. The index acetabular in neutral position and with abduction of hips is similar with high statistical significance, according to the analysis of correlation of Pearson. Based on the ROC curve, the acetabular index in frog position has a high sensitivity and specificity.

Discussion:

Therefore, the measurement of the acetabular index in position with hip abduction, has high reliability to achieve a correct diagnosis.