6 months old female baby with apparent shortening of the right lower limb..Xray shows the following features.Identify this condition:
B. Developmental Dysplasia of Hip
C. Coxa Vara
D. Acetabular immaturity
Ans:B. Developmental Dysplasia of Hip.
Typical radiographic evaluation of developmental dysplasia of hip (DDH).
- From anteroposterior radiograph of hips, horizontal line (Hilgenreiner line) is drawn between each triradiate cartilage.
- Next, lines are drawn perpendicular to Hilgenreiner line through superolateral edge of acetabulum (Perkin line), dividing hip into 4 quadrants.
- Proximal medial femur should be in lower medial quadrant, or ossific nucleus of femoral head, if present (usually observed in patients aged 4-7 months), should be in lower medial quadrant. Acetabular index is angle between Hilgenreiner line and line drawn from triradiate cartilage to lateral edge of acetabulum.
- Typically, this angle decreases with age and should measure less than 20° by 2 years of age.
- Shenton line is drawn from medial aspect of femoral neck to inferior border of pubic rami. It should create smooth arc that is not disrupted. Disruption of Shenton line indicates presence of some degree of hip subluxation.
Putti’s triad for developmental dysplasia of the hip include :
- Superolateral displacement of proximal femur .
- Increase in acetabular angle.
- Small capital femoral epiphysis.