Clinical Presentation

A 1-week-old female is referred with a positive Ortolani test.

Figure 92A

Figure 92B

Imaging Findings

Figure 92C Coronal sonogram of the hip depicts superolateral subluxation of the femoral head (FH). There is uplifting of labrum (L). The a angle (A) is formed by a line drawn parallel to the straight iliac echo (line 1) and a crossing line (line 2) drawn parallel to acetabular echogenic margin.

Figure 92D Coronal hip sonogram depicts femoral head (FH) well covered by echogenic labrum (L). Alpha (A) and β (B) angles are within normal limits. The deepest portion of the acetabulum is demonstrated based on visualization of triradiate cartilage. Gluteus medius (GM) spans hip joint in coronal plane. Arrows depict echogenic iliac margin. Arrowheads depict cartilaginous acetabulum.

Diagnosis

Developmental dysplasia of the hip (DDH) with dislocation

Differential Diagnosis

Dislocation related to:

• Trauma
  
• Neonatal sepsis (usually clinical findings)

Discussion

Background

DDH constitutes a spectrum of abnormalities ranging from minor neonatal instability to frank irreducible dislocation. The disorder is dynamic, with the potential to improve or worsen over time, and evolves prenatally (36–40 weeks) or postnatally (98%). The remaining cases are teratogenic, initiating early in development of the fetal hip. The incidence of hip instability detected at birth is 1 to 2%; however, the vast majority of these cases reflect transient instability and resolve. The quoted incidence of DDH is ~1 in 1000. Girls have a significantly higher incidence compared with boys (5:1). Lack of fetal mobility as seen in breech presentations has associated DDH in up to 23%. Two thirds of cases involve first-born children, with an overall familial incidence of 20%.

Etiology

Clinical Findings