Developmental Dysplasia of the Hip (DDH) in a 2-Year-Old Child
DNB Orthopaedics • May 2024 • Paper II • 10 Marks
Introduction
Developmental dysplasia of the hip (DDH) represents a spectrum of abnormalities involving the developing hip joint, ranging from mild acetabular dysplasia and instability to subluxation and complete dislocation.
The term “developmental” is preferred to “congenital” because the abnormality may be present at birth or may develop during infancy as the hip continues to mature.
Central concept: A concentrically reduced femoral head is the most important stimulus for normal acetabular development.
Spectrum of DDH
NORMAL HIP ↓ Acetabular dysplasia ↓ Hip instability ↓ Subluxation ↓ Dislocation ↓ Untreated chronic dislocation
Risk Factors
- Female sex
- Breech presentation
- Positive family history
- First-born child
- Oligohydramnios
- Large birth weight / intrauterine crowding
- Postnatal tight swaddling with hips extended and adducted
- Associated packaging disorders such as torticollis and metatarsus adductus
High-yield risk combination: female + breech + family history.
A. Pathoanatomy of DDH
In a persistently dislocated hip, both the acetabulum and proximal femur undergo progressive secondary changes.
Acetabular changes
- Shallow acetabulum
- Increased acetabular index
- Deficient anterosuperior acetabular coverage
- Hypertrophied pulvinar occupying the acetabulum
- Hypertrophied transverse acetabular ligament
- Inverted / hypertrophied limbus