Is developmental dysplasia of the hip (DDH) common in breech babies and how can it be treated if an ultrasound scan shows an angle just above the normal range in a 1-week-old baby?

Developmental Dysplasia of the Hip in Breech Babies: Diagnosis and Management

Breech babies have a significantly higher risk of developmental dysplasia of the hip (DDH), and ultrasound screening is recommended for all female breech infants and should be considered for male breech infants, even with a normal physical examination. 1

Prevalence and Risk Factors

• DDH affects approximately 1.5 in 1,000 Caucasian Americans, with higher incidence in:

  • Female infants (4-8 times more common)
  • Breech position (major risk factor)
  • Firstborns
  • Large infants
  • Those with family history of DDH 1

• Breech position is a significant risk factor due to:

  • Mechanical factors (reduced in-utero space)
  • Movement restriction
  • Extreme hip flexion with knee extension
  • Shortening and contracture of the iliopsoas muscle 1

Diagnostic Approach for Your Niece

Interpretation of Ultrasound Findings

For a 1-week-old with an alpha angle just above normal range:

• Normal alpha angle is >60° (Graf Type I) 2
• Alpha angle 50-59° in infants <3 months is classified as:
  • Type IIa+ (55-59°): Immature but likely to normalize
  • Type IIa- (50-54°): Immature with higher risk of not resolving 2
• Your niece's "angle just above normal range" suggests a Type IIa hip

Management Recommendations

1. For Type IIa hips (alpha angle 50-59°) in infants <3 months:

   • Observation without bracing is appropriate 2, 1
   • These hips require follow-up but no immediate treatment
   • 60-80% of cases identified on physical exam and >90% on ultrasound resolve spontaneously 1

2. Follow-up protocol:

   • Clinical re-examination in 2-4 weeks
   • Repeat ultrasound at 6-8 weeks of age
   • If alpha angle improves, continue observation
   • If alpha angle worsens or doesn't improve by 3 months of age, referral for treatment may be necessary 2

Important Considerations

Timing of Imaging

• The optimal timing for screening ultrasound is after 2 weeks of age 1
• For infants 0-4 weeks: Clinical examination is primary 1
• For infants 4 weeks-4 months: Ultrasound is the preferred imaging modality 1
• For infants 4-6 months: Radiograph of the pelvis becomes preferred 1

Warning Signs to Monitor

• Limited hip abduction (most important sign after 2-3 months)
• Asymmetric thigh folds
• Leg length discrepancy 2, 1

Potential Complications

• Delayed diagnosis increases risk for complications requiring surgical correction
• Overtreatment carries risk of iatrogenic avascular necrosis of the femoral head 2, 1
• Untreated DDH can lead to premature osteoarthritis and long-term mobility issues 1

Conclusion for Your Niece's Case

For a 1-week-old breech baby with an alpha angle just above normal range:

1. Observation without bracing is appropriate at this time
2. Schedule follow-up examination and repeat ultrasound at 6-8 weeks
3. If the alpha angle normalizes (>60°), continue routine monitoring
4. If the alpha angle worsens or doesn't improve by 3 months, orthopedic referral for possible treatment is recommended

This approach balances the risks of both undertreatment and overtreatment while providing appropriate monitoring for this common condition in breech babies.