**6. Diagnostic imaging**

Diagnosis in the newborn is clinical and is made through the hereditarily and perinatal antecedents, as well as by the maneuvers of the deliberate exploration. In case of doubt, an echo-sonogram of the hip is used by qualified imaging specialists; It should be noted that radiographs are not useful before 4 months of extrauterine life.

Ultrasonographic diagnosis is made in the newborn and at any other stage of life; It is performed through the static and dynamic test of the hip, with the Graf technique, where the angles α and β are measured in each test. Graph I is considered a normal hip in the child with α >60° and β <55°; Graf II is considered a physiologically immature hip with α 44–59° and β 55–77°; Graph III and IV as a dislocated or dislocated hip with α < 43° and β > 77° (**Figure 6a b**) [38, 39].

The radiological diagnosis is based on the findings of the anteroposterior pelvic plates in neutral position and abducted 45° (Lowestein position). The study is useful from the fourth month of age, since the ossification nuclei of the femoral head have already appeared. The following radiographic data can be found: Hilgenrainer's line is a horizontal one that passes through the triradial cartilages of the iliac; the Perkins or Ombredanne line is a vertical line that passes perpendicularly through the outermost edge of the acetabulum until it surpasses the Hilgenreiner line, forming the Putti quadrants (the femoral head must be in the lower inner quadrant, normally). The angle formed with line that start from the outer edge of the acetabulum and pass through the bottom of the acetabulum until reaching Hilgenreiner line, and Hilgenreiner line, gives us the acetabular index that must be less than 30° (**Figure 7a**) [11, 17].

The Shenton's arch, passes through the lower edge of the pubis and continues with the lower edge of the femoral neck, forming a normal arch; if there is distortion of this arch, it is considered a dislocated hip (**Figure 7a**) [11, 17].

**Figure 7** a represents the anteroposterior plate of the pelvis in abduction; Look for the Von Rossen sign by drawing a line along the axis of the femur to the midline of the spine (King's midline); the line usually passes through the acetabulum [11, 17].

**Figure 6.** *a. Graf technique left hip. b. Graf technique right hip.*

*Diagnosis of Developmental Dysplasia of the Hip in Newborns and Infants DOI: http://dx.doi.org/10.5772/intechopen.104085*

**Figure 7.** *a. AP of the hip. b. Lowenstein. Source: Dr. Jaime González-García.*

Diagnosis at an early stage (under 2 months): in the dislocated hip there is an increase in the acetabular index and absence of the peak of the acetabulum eyebrow. In the dislocated and subluxed hip, lateralization of the proximal internal end of the neck, Von Rossen sign, and alteration of Shenton's line are located [11, 17].

Late stage diagnosis: in addition to the above, there is Putti's triad (increased acetabular index, the proximal end of the femur outside and above the Perkins line, as well as delayed ossification of the nucleus of the femoral head) [11, 17].
