Developmental Dysplasia of the Hip

Aka: Developmental Dysplasia of the Hip, Congenital Hip Dislocation, Hip Dislocation in the Newborn, Congenital Hip Dysplasia

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II. Definitions

  1. Developmental Dysplasia of the Hip (DDH)
    1. Acetabulum or femoral head dysgenesis resulting in hip incongruity in infants
    2. Spectrum from hip laxity and instability to hip subluxation and dislocations

III. Epidemiology

  1. Incidence
    1. Hip instability at birth: 0.1 to 0.3%
  2. Girls 9 times more often affected than boys
  3. Usually unilateral, but bilateral is common

IV. Risk Factors

  1. Breech Presentation (Odds Ratio 6)
    1. Unstable hips found in >10% of Breech infants
  2. Female gender (Odds Ratio 4.3)
  3. First born (Odds Ratio 2.7)
  4. Family History (positive in up to one third of cases)
    1. One affected sibling: 6% risk
    2. One affected parent: 12% risk
    3. One affected sibling and one affected parent: 36%
  5. Oligohydramnios
  6. Large for Gestational Age infant

V. Pathophysiology

  1. Femoral head dislocates from acetabulum
  2. Results from Acetabular Dysplasia (shallow acetabulum)
    1. Results in subluxed, dislocated or unstable hip
  3. Left hip is affected in 60% of cases
    1. Remainder are right (20%) and bilateral (20%)

VI. Types

  1. Classic Congenital Hip Dislocation
  2. Congenital Abduction Contracture of the Hip
  3. Teratologic Congenital Hip Dislocation
    1. Severe, prenatal fixed dislocation
    2. Associated with genetic and neuromuscular disorders

VII. Associated Conditions

  1. Congenital Torticollis
  2. Breech Presentation in utero
  3. First degree relative with hip dysplasia history
  4. Clubfoot
  5. Metatarsus Adductus
  6. Torticollis

VIII. Symptoms

  1. Painless limp in toddler (best if diagnosed earlier)

IX. Signs

  1. Dislocation and Relocation maneuvers
    1. Useful only in first few weeks to months of life
      1. Accuracy decreases as ligamentous laxity resolves
    2. Repeat exam in 2 weeks if equivocal results
    3. Tests
      1. Ortolani Test (relocate hip into acetabulum)
      2. Barlow's Test (attempt to sublux unstable hip)
  2. Pelvis symmetry
    1. Galeazzi's Sign (compare the 2 femur lengths)
    2. Observe for asymmetric skin folds
  3. Hip Range of Motion
    1. Abduction tested with hips flexed to 90 degrees
    2. Abnormal if abduction <60 degrees or less than opposite side by at least 20 degrees difference

X. Imaging

  1. Dynamic Hip Ultrasound (infant aged 1-6 months)
    1. Diagnostic for Congenital Hip Dislocation
    2. Evaluates for subluxation and reducibility
    3. High False Positive Rate in age <6 weeks
      1. However, 90% Negative Predictive Value
    4. Grading based on Graf System
      1. Grade I: No abnormality
      2. Grade IV: Frank dislocation
  2. Hip XRay
    1. Not diagnostic for dislocation until >6 months
      1. Femoral head not calcified under age 4-6 months
      2. Diagnostic for Acetabular Dysplasia
        1. Abnormal acetabular fossa will be seen
    2. Evaluated with reference lines drawn over AP XRay
      1. Hilgenreiner's Line
        1. Horizontal line through triradiate cartilages
      2. Perkin's Line
        1. Vertical line along each lateral acetabulum
      3. Shenton's Line
        1. Femoral neck medial border
        2. Superior border of obturator foramen

XI. Evaluation: Exam Findings

  1. Hip click
    1. Palpable or audible, high-pitched click on Ortolani or Barlow Maneuver
    2. Hip clicks are caused by soft tissue movement and are not related to hip instability or dislocation
    3. Distinguish the benign hip click from the pathologic Hip Clunk (dislocation)
      1. Hip clicks are benign and require no further evaluation
      2. Hip Clunks are managed as Developmental Dysplasia of the Hip (see below)
  2. Hip Clunk
    1. Distinct, palpable/audible shift of the femoral head as it is relocated (Ortolani) or dislocated (Barlow)
    2. Hip Clunk suggests Developmental Dysplasia of the Hip, with dislocation or subluxation
  3. Hip instability or laxity
    1. May feel as a tennis ball might move within a cereal bowl without frankly dislocating (no Hip Clunk)
    2. Represents a loose fit of the femoral head with the acetabulum (without subluxation or dislocation)
    3. Relatively mild findings on the spectrum of Developmental Dysplasia of the Hip
  4. Limited Hip Range of Motion
    1. Reduced hip abduction (<60 degrees or more than 20 degrees difference between sides)
    2. Requires additional evaluation for Developmental Dysplasia of the Hip
  5. Hip subluxation
    1. Femoral head approaches the edge of the acetabulum but does not fully dislocate
    2. A soft clunk may be palpable on Ortolani or Barlow Maneuvers
  6. Hip Dislocation
    1. Femoral head completely escapes the acetabulum
    2. Most severe on the spectrum of Developmental Dysplasia of the Hip

XII. Evaluation: Increased Developmental Dysplasia of the Hip Risk

  1. Indications
    1. Breech Presentation OR
    2. Two or more DDH risk factors (Female gender, first-degree relative Family History)
  2. Approach
    1. Equivocal or positive exam results
      1. Refer to orthopedics
    2. Normal exam
      1. Consider Hip Ultrasound at age 4-6 weeks
      2. Repeat exam in 2 weeks and well child exam
      3. Refer to orthopedics for findings suggestive of DDH

XIII. Evaluation: Standard Developmental Dysplasia of the Hip Risk

  1. Approach to significant findings (hip subluxation, Hip Dislocation or age over 6 months with findings)
    1. Referral to orthopedics
  2. Approach to mild instability or equivocal exam findings
    1. Repeat exam in 2 weeks
    2. Hip subluxation or dislocation
      1. Refer to orthopedics
    3. Persistent mild hip instability
      1. Obtain Hip Ultrasound or repeat exam every 2 weeks

XIV. Management

  1. Management indicated for hip instability beyond 5 days of life
  2. Step 0: Observation
    1. Indicated only in mild instability for age <6 weeks
    2. Repeat examinations every 2 weeks for first 6 weeks of life
    3. Persistent instability or other DDH findings prompt orthopedic referral for Pavlik Harness
  3. Step 1: Pavlik Harness
    1. Indicated as first-line if age <6 months for frankly dislocated or dislocatable hips
    2. Start with harness trial for 3-4 weeks
    3. Splints hips in flexed and abducted position
    4. Long-term effectiveness: 95% (80% if frank dislocation)
    5. Ultrasound should demonstrate reduction at 3 weeks
      1. Reduced: Continue harness for >6 weeks
      2. Not Reduced: Go to Step 2
    6. Avascular necrosis risk: 0-14% overall, <2% for infants with early Splinting
  4. Step 2: Closed Reduction and Casting by Orthopedics
    1. Indications
      1. No reduction with Pavlik Harness in 3-4 weeks
      2. Children over age 6 months
    2. Attempted closed reduction under arthrogram
    3. Hip Spica Casting for 6 weeks
    4. Positioning confirmed by post-op MRI or CT
    5. Avascular necrosis risk similar to Pavlik Harness (0-14% overall, <2% for infants with early Splinting)
  5. Step 3: Surgical Open reduction
    1. Indicated in refractory cases
    2. Requires multi-step procedure
      1. Tendon lengthening
      2. Clearing tissues obstructing relocation
      3. Tightening hip capsule
      4. Osteotomy if performed after age 18 month
    3. Complications
      1. Re-disclocation
      2. Avascular necrosis (5-60% risk)

XV. Course

  1. Many unstable hips at birth stabilize by 5 days of life

XVI. Prognosis

  1. Delayed treatment risks worse outcomes
  2. Monitor children with imaging until skeleton mature

XVII. Complications

  1. Hip Osteonecrosis
  2. Premature Osteoarthritis of the hip as early as late teen

XVIII. Prevention

  1. Screening guidelines vary by organization (AAP, AAFP, USPTF)
    1. USPTF and AAFP found insufficient evidence for universal screening
  2. American Academy of Pediatrics (AAP) recommendations
    1. Screen all newborns with Ortolani Maneuver and Barlow Maneuver
    2. Repeat Hip Exam at routine visits for the first year of life
    3. High risk patients (e.g. Breech, Family History) should be screened with Hip Ultrasound

XIX. References

  1. (2006) Pediatrics 117:898-902 [PubMed]
  2. Harding (1997) J Pediatr Orthop 17:1149-52 [PubMed]
  3. Jackson (2014) Am Fam Physician 90(12): 843-50 [PubMed]
  4. Storer (2006) Am Fam Physician 74(8):1310-6 [PubMed]
  5. Vitale (2001) J Am Acad Orthop Surg 9:401-11 [PubMed]

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