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  • A disorder of abnormal development resulting in dysplasia and possible subluxation or dislocation of the hip secondary to capsular laxity and mechanical factors
  • DDH encompasses a spectrum of disease that includes 
    • dysplasia
      •  a shallow or underdeveloped acetabulum
    • subluxation
    • dislocation
    • teratologic hip
      • dislocated in utero and irreducible on neonatal exam
      • presents with a pseudoacetabulum
      • associated with neuromuscular conditions and genetic disorders
        • commonly seen with arthrogryposis, myelomeningocele, Larsen's syndrome
    • late (adolescent) dysplasia 
      • mechanically stable and reduced but dysplastic
  • Epidemiology
    • incidence
      • most common orthopaedic disorder in newborns
      • dysplasia is 1:100
      • dislocation is 1:1000
    • location
      • most common in left hips in females
      • bilateral in 20%
    • demographics
      • more commonly seen in Native Americans and Laplanders
      • rarely seen in African Americans
    • risk factors
      • firstborn
      • female (6:1 over males)
      • breech
      • family history
      • oligohydramnios
  • Pathophysiology
    • initial instability thought to be caused by maternal and fetal laxity, genetic laxity, and intrauterine and postnatal malpositioning
    • pathoanatomy
      • initial instability leads to dysplasia
      • dysplasia leads to gradual dislocation
    • typical deficiency is anterior or anterolateral acetabulum
      • in spastic cerebral palsy, acetabular deficiency is posterior-superior q
  • Associated conditions
    • associated with "packaging" deformities which include
      • congenital muscular torticollis (20%)
      • metatarsus adductus (10%)
      • congenital knee dislocation
    • conditions characterized by increased amounts of type III collagen
  • Can be classified as a spectrum of disease involvement (phases)
    • dislocated
      • Ortolani-positive early when reducible; Ortolani-negative late when irreducible
    • dislocatable
      • Barlow-positive
    • subluxatable
      • Barlow-suggestive
  • Physical exam (< 3 months)
    • mainstay of physical diagnosis is palpable hip subluxation/dislocation on the exam 
      • Barlow 
        • dislocates a dislocatable hip by adduction and depression of the flexed femur
      • Ortolani  
        • reduces a dislocated hip by elevation and abduction of the flexed femur
      • Galeazzi (Allis)  
        • apparent limb length discrepancy due to a unilateral dislocated hip with hip flexed at 90 degrees and feet on the table
        • femur appears shortened on dislocated side
    • hip clicks are nonspecific findings
    • Barlow and Ortolani a rarely positive after 3 months of age because of soft-tissue contractures about the hip
  • Physical exam (> 3 months to 1 year)
    • limitations in hip abduction
      • most sensitive test once contractures have begun to occur
    • occurs as laxity resolves and stiffness begins to occur
    • decreased symmetrically in bilateral dislocations
    • leg length discrepancy predominate
  • Physical exam (> 1 year - walking child)
    • pelvic obliquity
    • lumbar lordosis
      • in response to hip contractures resulting from bilateral dislocations in a child of walking age
    • Trendelenburg gait 
      • results from abductor insufficiency
    • toe walking
      • compensate for the relative shortening of the affected side
  • Radiograph
    • indications
      • becomes primary imaging modality at 4-6 mo after the femoral head begins to ossify
      • positive physical exam
      • leg length discrepancy
    • recommended views
      • AP of pelvis
    • measurements
      • hip dislocation
        • Hilgenreiner's line   
          • a horizontal line through right and left triradiate cartilage
          • femoral head ossification should be inferior to this line
        • Perkin's line  
          • line perpendicular line to Hilgenreiner's through a point at lateral margin of acetabulum
          • femoral head ossification should be medial to this line
        • Shenton's line  
          • arc along inferior border of femoral neck and superior margin of obturator foramen
          • arc line should be continuous
        • delayed ossification of the femoral head is seen in cases of dislocation
      • hip dysplasia
        • acetabular index (AI)  
          • the angle formed by a line drawn from a point on the lateral triradiate cartilage to point on lateral margin of acetabulum and Hilgenreiners line
          • should be less than 25° in patients older than 6 months
        • center-edge angle (CEA) of Wiberg 
          • the angle formed by a vertical line from the center of the femoral head and a line from the center of the femoral head to the lateral edge of the acetabulum
          • less than 20° is considered abnormal
          • reliable only in patients over the age of 5 years
        • acetabular teardrop not typically present prior to hip reduction for chronic dislocations since birth 
          • development of teardrop after reduction is thought to be a good prognostic sign for hip function
  • Ultrasound
    • indications
      • primary imaging modality from birth to 4 months
        • may produce spurious results if performed before 4-6 weeks of age
      • positive physical exam
      • risk factors (family history or breech presentation)
        • the AAP recommends a US study at 6 weeks in patients who are considered high risk (family history or breech presentation) despite normal exam
      • monitoring of reduction during Pavlik harness treatment 
      • most studies show is not cost effective for routine screening
    • findings
      • evaluates for acetabular dysplasia and/or the presence of a hip dislocation
      •  allows view of bony acetabular anatomy, femoral head, labrum, ligamentum teres, hip capsule  
      • normal ultrasound in patients with soft-tissue 'clicks' will have normal acetabular development
    • measurements
      • alpha angle 
        • the angle created by lines along the bony acetabulum and the ilium
        • normal is greater than 60°
      • beta angle
        • the angle created by lines along the labrum and the ilium
        • normal is less than 55°
      • femoral head is normally bisected by a line drawn down from the ilium
  • Arthrogram  q 
    • indications
      • used to confirm reduction after closed reduction under anesthesia
    • help identify possible blocks to reduction
      • inverted labrum
        • labrum enhances the depth of the acetabulum by 20% to 50% and contributes
          to the growth of the acetabular rim
        • in the older infant with DDH the labrum may be inverted and may mechanically block concentric reduction of the hip
      • inverted limbus
        • represents a pathologic response of the acetabulum to abnormal pressures caused by superior migration of the head
        • consists of fibrous tissue
      • transverse acetabular ligament
      • hip capsule is constricted by iliopsoas tendon causing hour-glass deformity of the capsule  
      • pulvinar
      • ligamentum teres
  • CT
    • CT is historically the study of choice to evaluate reduction of the hip after closed reduction and spica casting 
  • MRI
    • increasingly used to evaluate reduction of hip after closed reduction and spica casting, to minimize radiation compared to CT.
  • All infants require screening
    • physical exam
      • successful screening requires repetitive screening until walking age
    • ultrasound
      • ultrasound screening of all infants occurs in many countries, however, it has not been proven to be cost-effective
      • USA recommendations is to perform ultrasound at 4 to 6 weeks in patients with
        • risk factors
        • positive physical findings
      • utilized to follow Pavlik treatment or for equivocal exams
Treatment in Children
  • Nonoperative
    • abduction splinting/bracing (Pavlik harness)   
      • indications
        • DDH < 6 months of age and reducible hip
        • Pavlik harness treatment is contraindicated in teratologic hip dislocations
        • is a dynamic splint that requires normal muscle function for successful outcomes
          • contraindicated in patients with spina bifida or spasticity
      • outcomes
        • overall Pavlik harness has a success rate of 90%
          • dependent upon age at initiation of treatment and time spent in the harness
        • abandon Pavlik harness treatment if not successful after 3-4 weeks 
        • If Pavlik harness fails, consider converting to semi-rigid abduction brace with weekly ultrasounds for an addition 3-4 weeks before considering further intervention  
    • closed reduction and spica casting 
      • indications
        • DDH in 6 - 18 months of age
        • failure of Pavlik treatment
      • arthrography performed at the time of reduction
        • medial dye pool >7mm associated with poor outcomes and osteonecrosis 
        • wide abduction associated with osteonecrosis (aim at <55 degrees abduction)
  • Operative
    • open reduction and spica casting   
      • indications
        • DDH in patient >18 months of age
        • failure of closed reduction 
    • open reduction and femoral osteotomy 
      • indications
        • DDH > 2 yr with residual hip dysplasia 
        • anatomic changes on femoral side (e.g., femoral anteversion, coxa valga)
        • femoral head should be congruently reduced with satisfactory ROM, and reasonable femoral sphericity
        • best in younger children (< 4 yr)
          • after 4 yr, pelvic osteotomies are utilized
    • open reduction and pelvic osteotomy 
      • indications
        • DDH > 2 yr with residual hip dysplasia 
        • severe dysplasia accompanied by significant radiographic changes on the acetabular side (increased acetabular index) 
        • used more commonly in older children (> 4 yr)
          • decreased potential for acetabular remodeling as child ages
  • Abduction splinting/bracing (Pavlik harness) 
    • goals
      • treatment is based on an early concentric reduction in order to prevent future degeneration of the hip
      • risk, complexity, and complications are increased with delays in diagnosis
    • position in bracing
      • the anterior straps flex the hips to 90-100° flexion and prevent extension
      • the posterior prevent adduction of the hips
    • extreme positions can cause
      • AVN due to impingement of the posterosuperior retinacular branch of the medial femoral circumflex artery
        • seen with extreme abduction (> 60°)
        • placement of abduction within 'safe zone'
      • transient femoral nerve palsy
        • seen with hyperflexion 
    • discontinue if hip is not reduced by 3-4 weeks to prevent Pavlik disease
      • erosion of the pelvis superior to the acetabulum and prevention of the development of the posterior wall of the acetabulum
    • worn for 23 hours/day for at least 6 weeks or until hip is stable
      • wean out of harness over 6-8 weeks after hip has stabilized until normal anatomy develops
    • confirm position with ultrasound or xray and monitor every 4-6 week
  • Closed reduction and spica casting
    • performed under general anesthesia
      • excessive force can result in AVN
    • arthrogram used to confirm the reduction
      • concentric reduction must be obtained with less than 5mm of contrast pooling medial to femoral head and the limbus must not be interposed
      • the arthrogram will also help identify anatomic blocks to reduction:
    • spica casting
      • following reduction immobilize in a spica cast with hip flexion of 100 deg. and abduction of 45 deg with neutral rotation for 3 months
        • 'human position'
        • change cast at 6 weeks
      • adductor tenotomy performed if the patient has an unstable safe zone
        • used if excessive abduction required to maintain the reduction
      • confirm reduction with CT scan in spica cast with selective cuts to minimize radiation to the child  
  • Open reduction 
    • anterior approach (Smith-Peterson) most common to decrease risk to the medial femoral circumflex artery 
      • capsulorrhaphy can be performed after reduction
      • used if the patient is older than 12 months
    • medial approaches 
      • pros
        • directly addresses block to reduction
        • can be used in patients under 12 months of age
        • less blood loss
      • cons
        • unable to perform a capsulorrhaphy
        • higher association of AVN
      • Ludloff medial approach 
        • between pectineus and adductor longus and brevis)
      • Weinstein anteromedial approach 
        • between neurovascular bundle and pectineus 
      • Ferguson posteromedial approach 
        • superficially between adductor longus and gracilis
        • deep between adductor brevis and adductor magnus
    • remove possible anatomic blocks to reduction
      • iliopsoas contracture, capsular constriction, inverted labrum, pulvinar, hypertrophied ligamentum teres
    • adductor tenotomy performed if the patient has an unstable safe zone
      • if excessive abduction required to maintain the reduction
    • immobilize in functional position of 15° of flexion, 15° of abduction and neutral rotation
  • Femoral Osteotomy (VRDO)  
    • used to correct excessive femoral anteversion and/or valgus
    • femoral osteotomy and shortening may be needed to prevent AVN
      • decrease tension produced by reduction of a previously dislocated hip
  • Pelvic Osteotomies 
    • indications
      • increase anterior or anterolateral coverage
      • used after reduction is confirmed on abduction-internal rotation views and satisfactory ROM has been obtained

Reconstructive Pelvic Osteotomies

Younger patients typically with open triradiate cartilage

Single cut above acetabulum through the ilium to sciatic notch. Acetabulum hinges through the pubic symphysis. The redirectional osteotomy can provide 20-25° lateral and 10-15° anterior coverage (coverage limitations in anterolateral head). May lengthen leg up to 1 cm.


Favored in older children because their symphysis pubis does not rotate well. Performed when open triradiate cartilages are present

Salter osteotomy plus additional cuts through superior and inferior pubic rami. Acetabular reorientation procedure.

PAO (Ganz) 

Triradiate cartilage must be closed in order to perform 

Involves multiple osteotomies in the pubis, ilium, and ischium near the acetabulum. This allows improved three-dimensional correction of the acetabulum configuration. It is technically the most challenging. Posterior column and pelvic ring remain intact and patients are allowed to weight bear early  

Pemberton For moderate to severe DDH; most versatile; triradiate cartilage must be open

Osteotomy starts approximately 10 to 15 mm above the AIIS, proceeds posteriorly, and ends at the level of the ilioischial limb of the triradiate cartilage (halfway between the sciatic notch and the posterior acetabular rim). Osteotomy hinges at the triradiate cartilage posteriorly and the symphysis pubis anteriorly.  This osteotomy does do not enter the sciatic notch and is therefore stable and does not need internal fixation. Reduces acetabular volume


Favored in neuromuscular dislocations (CP) and patients with posterior acetabular deficiency; for severe cases

Osteotomy from acetabular roof to triradiate cartilage (incomplete cuts through pericapsular portion of the innominate bone). The acetabular configuration changes by hinging through the triradiate cartilage. This osteotomy does do not enter sciatic notch and is therefore stable and does not need internal fixation. Reduces the acetabular volume

Dial Technically difficult and rarely used

The dial or spherical osteotomy leaves the medial wall or teardrop in its original position and, as a result, is intra-articular. 

Salvage pelvic osteotomies
Shelf Salvage procedure performed in patients older 8yr

Add bone to the lateral weight-bearing aspect of acetabulum by placing an extra-articular buttress of bone over the subluxed femoral head. Depends on fibrocartilge metaplasia for successful results.

Chiari Salvage procedure for pateints with inadequate femoral head coverage and  when a concentric reduction can not be obtained

Make cut above acetabulum to sciatic notch and shift ileum lateral beyond edge of acetabulum. Depends on fibrocartilge metaplasia for successful results. Medializes the acetabulum via iliac osteotomy.

  • Osteonecrosis
    • seen with all forms of treatment
    • increased rates associated with
      • excessive or forceful abduction
      • previous failed closed treatment
      • repeat surgery
    • diagnosis based on radiographic findings that include
      • failure of appearance or growth of the ossific nucleus 1 year after the reduction
      • broadening of the femoral neck 
      • increased density and fragmentation of ossified femoral head
      • residual deformity of proximal femur after ossification
  • Delayed diagnosis
    • bilateral dislocations
      • patients typically functions better if hips are not reduced if 6 years of age or older
    • unilateral dislocation
      • better outcomes without surgical treatment if the patient is 8 years of age or older
      • epiphysiodesis can be performed for treatment of limb length discrepancy
  • Recurrence
    • approximately 10% with appropriate treatment
    • requires radiographic follow-up until skeletal maturity
  • Transient femoral nerve palsy
    • seen with excessive flexion during Pavlik bracing   


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