DDH

Developmental Dysplasia of the Hip (DDH)

Overview

DDH - CDH (Congenital Dislocation of Hip)

Dr. Sultan Almisfer

Nomenclature

• CDH: Congenital Dislocation of the Hip
• DDH: Developmental Dysplasia of the Hip
• XCHD: (Congenital Heart Disease)!

Spectrum of Diseases

• Different etiologies, pathologies, and natural history
• Affects proximal femur and acetabulum
• Initial pathology is congenital, but:
  • Progresses if untreated
• Does not always result in dislocation

CDH Spectrum

• Teratologic hip:
  • Fixed dislocation at birth, often with other major anomalies
• Dislocated hip:
  • May or may not be reducible
• Unstable hip:
  • Dislocatable - Reducible
• Acetabular dysplasia:
  • Shallow acetabulum

Incidence

• Hip instability at birth: 0.5 – 1%
• Classic DDH: 0.1%
• Mild dysplasia: Substantial
  • Up to 50% of hip arthritis in ladies have underlying hip dysplasia

Etiology

Multi-factorial Causes

• Ligament laxity
• Hormonal factors:
  • Estrogen, Relaxin: by mothers
  • May affect baby girls more – receptors?
• Familial (congenital):
  • Mild – Moderate – Sever – Ehler Danlos syndrome

Genetic FactorsZ

• Females: 4-6 X more than males
• Twin studies:
  • If one twin has DDH, the incidence of DDH in the second twin is:
    • Monozygotic: 38%
    • Dizygotic: 3% (similar to other siblings)

Mechanical Factors

• Prenatal:
  • Breach position:
    • Normally: 2-4%, In CDH: 16%
  • Oligohydramnious – Primigravida
  • Torticollis – metatarsus adductus
• Postnatal:
  • Swaddling / strapping hips adducted and extended, and knees extended

Risk Factors

• Positive family history: 10X
• A baby girl: 4-6 X
• Breach presentation: 5-10 X
• Torticollis: DDH in 10-20% of cases
• Foot deformities:
  • Calcaneo-valgus and metatarsus adductus
• Knee deformities:
  • Hyperextension and dislocation (Teratologic)

When risk factors are present:

• The infant should be examined repeatedly
• The hips should be imaged: (U/S or X-ray)

Clinical Examination

Physical Examination by Age Group

Neonatal Examination

• Ortolani Test: (reduces a dislocated hip)
  • Feel a clunk
  • Not hear a click!

• Barlow Test: (dislocated a reduced hip)!
  • Feel a clunk
  • Not hear a click!

Visual Inspection

• Look for:
  • Externally rotated hip
  • Lateralized contour
  • Wide perineum (in bilateral cases)
  • Asymmetrical folds (Anterior - Posterior)
  • Shortening (Galeazzi test)

Range of Motion

• Move:
  • Limitation of abduction in flexion
  • Careful in bilateral cases
    • Symmetrical limitation
    • If abduction < 60° bilaterally: abnormal

The importance of a lollipop Galeazzi / Limited abduction in flexion

Functional Assessment

• Trendelenburg Sign:
  • Unilateral: Trendelenburg gait
  • Bilateral: Waddling gait

Examination Summary by Age

• Neonatal: Limited abduction, Ortolani/Barlow (up to 3m)
• Toddler: Shortening, limited abduction
• Walker: Shortening, limited abduction, Trendelenburg

Imaging

Ultrasound

• In early infancy U/S more reliable than x-ray
• Good in expert hands
• Incidence of hip stability declines rapidly to 50% within the first week of neonatal life
• Better to delay U/S to 4-6 weeks of age

Radiologyz

• After 3 months: more reliable
• Early infancy: not reliable - U/S better

• AP abduction view
  • Long axis of femur normally passes through acetabulum

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After 6 months:

• Clearly shows dislocation
• Size of femoral head ossific center
• Horizontal line through the tri-radiate cartilage

Position Assessment:

• Dislocated: Above the horizontal line
• Normal: Below the horizontal line

Radiographic Measurements

Perpendicular line from edge of acetabulum:

• Dislocated: Lateral to perpendicular line
• Normal: Medial to perpendicular line

Acetabular angle (acetabular index):

• Normal: ≤ 25°
• Dislocated: > 35°

Shenton’s line:

Treatment

Treatment Goals

• Obtain concentric reduction
• In a non-traumatic fashion
  • Without disrupting the blood supply to femoral head

Treatment Principles

• Method depends on age
• The earlier started, the easier it is
• The earlier started, the better the results are
• Should be detected EARLY

Treatment by Age Group

Neonatal Hip Instability (Birth - 6 months)

• Most resolve spontaneously
• Initial approach:
  • Avoid adduction swaddle
  • Apply double diapers – to bring back!!
  • See at 2 weeks of age

• Unstable at 2 weeks:
  • Pavlik Harness
    • Dynamic, effective, safe

6-12 months of age

• Closed reduction & hip spica cast
• Arthrography-guided

12-24 months of age

• Surgery
• Open reduction & Acetabuloplasty (pelvic osteotomy)

Above 2 years of age

• Surgery
• Open reduction & Acetabuloplasty & Femoral shortening

Treatment Summary by Age

Age Range	Treatment Approach
Birth – 6m	Pavlik harness or hip spica
6-12m	Closed reduction under GA and hip spica
12-18m	Open reduction and Acetabuloplasty
2-8 years	Open reduction, Acetabuloplasty, and femoral shortening
Above 8 years	Open reduction, Acetabuloplasty cutting all three pelvic bones, and femoral shortening

DDH Summary

• Complex multi-factorial, endemic disease
• Identify at risk groups
• Learning proper examination methods
• The earlier we treat the easier it is
• The earlier we treat the better the results