Developmental Dysplasia Of The Hip (DDH)

Developmental Dysplasia Of The Hip (DDH) simply mean that there is a defect in the formation of the hip joint, which can range from mild dysplasia to irreducible dislocation.

Early diagnosis carries good prognosis, therefore UK health sectors has included this in their routine  screening program.

  • Incidence : 
    • 1 – 2 per 1000 live births
    • Male to female ratio is 1 : 4 – 8 
    • Left hip is more commonly affected 
    • 20% can be bilateral
   

Aetiology And Pathophysiology Of DDH

Aetiology is not properly understood.
But it is believed to be associated with abnormal laxity of the ligaments around the hip joint.
Several risk factors are identified for DDH.

Risk factors of DDH

  • Breech presentation
  • First born child
  • Female sex (M:F ratio is 1 : 4-8)
  • Family history of DDH
    • DDH in a first degree relative increases the risk by 10 folds)
  • Race
    • More common in native Americans than Africans, Japanese 


Diagnosis Of DDH

It is very important to diagnose the disease at the very early stage to ensure good prognosis.
  • Newborns babies
    • Neonatal examination should be performed within 72 hours
    • Two tests are performed in combination to increase the reliability of the diagnosis
      • Ortolani’s test
      • Barlow’s provocation test
    • The objective is to find whether the hip is unstable. the following are assessed
      • Dislocated hip, which can be reduced
      • No dislocation, but can be dislocated 
      • Can it be reduced 
    • In some cases the hip can be normal at birth

  • 3 months – 1.5 years 
    • Decreased abduction of the hip
    • Asymmetrical skin folds 
      • Not reliable 
      • As shown in the figure here
  • More than 1.5 years
    • Trendelenburg’s gait  
If any abnormality is detected of the hip joint (During examination, asymmetric skin folds), an ultrasound scan should be performed 
  • Ultrasonography of the hip
    • Best done at 2 weeks when the lax capsule tightens up 
  • Plain X-Ray is also helpful 
    • Acetabular index should be less than 30° 


Shenton’s line is an arc from the lesser trochanter, up the neck and inferior to the superior pubic ramus 

Hilgenreiner’s horizontal line is a transverse line through the triradiate cartilage 

Perkin’s vertical line is drawn at the lateral margin of the acetabulum (perpendicular to Hilgenreiner’s line)

Treatment Of DDH

Usually these patients are diagnosed during first 6 months of life 

  • Diagnosed during the first 6 months
    • Pelvic harness
      • Applied for 6 weeks
      • Monitor reduction by ultrasonography




Fig : Pelvic Harness

Pelvic harness allows controlled range of abduction and flexion 


  • Diagnosed at 6 – 18 months
    • Gentle closed reduction 
    • If failed – Athrogram to see any soft tissue block 
    • Open reduction, if necessary
       
  • 18 months onwards
    • Open reduction 

Follow up should be continued until the patient starts walking normally / up to 5 years (WHO recommendation) 



Complications Of DDH
  • Limp
  • Hip pain
  • Osteoarthritis is a long term complication


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