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Introduction
  • 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
      • first born
      • 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 instabiltiy 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
Classification
  • 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
Presentation
  • Physical exam (< 3 months)
    • mainstay of physical diagnosis is palpable hip subluxation/dislocation on 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 and knee flexed at 90 degrees
        • 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)
    • limitations in hip abduction
      • most sensitive test once contractures have began 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 relative shortening of affected side
Imaging
  • Radiograph
    • become primary imaging modality at 4-6 mo after the femoral head begins to ossify
      • hip dislocation
        • Hilgenreiner's line   
          • 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)  
          • angle formed by a line drawn from 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 
          • 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 
          • development of teardrop after reduction is thought to be good prognostic sign for hip function
  • Ultrasound
    • evaluates for acetabular dysplasia and/or the presence of a hip dislocation
      • useful before femoral head ossification (<4-6 mos)
      • may produce spurious results if performed before 4-6 weeks of age
    • allows view of bony acetabular anatomy, femoral head, labrum, ligamentum teres, hip capsule  
      • alpha angle 
        • angle created by lines along the bony acetabulum and the ilium
        • normal is greater than 60°
      • beta angle
        • 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
    • used as an adjunct only in patients at 3-4 weeks in patients who are considered high risk (family history and/or have an equivocal physical exam)
    • normal ultrasound in patients with soft-tissue 'clicks' will have normal acetabular development
    • allows for monitoring of reduction during Pavlik harness treatment
    • is not cost effective for routine screening
  • Arthrogram  q 
    • 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 study of choice to evaluate reduction of the hip after closed reduction and spica casting 
  • MRI
    • does not play significant role in primary diagnosis
Screening
  • 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 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, convert 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
  • 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
Techniques
  • Abduction splinting/bracing (Pavlik harness) 
    • goals
      • treatment is based on 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
      • goal is 90-100° flexion (controlled by anterior straps) and abduction of 50° (controlled by posterior straps)
    • 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 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 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 medial femoral circumflex artery 
      • capsulorrhaphy can be performed after reduction
      • used if patient is older than 12 months
    • other possible approaches include
      • medial adductor approach, variation  of Ludloff
        • 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
      • anteromedial approach 
      • posteromedial approach
    • remove possible anatomic blocks to reduction
      • iliopsoas contracture, capsular constriction, inverted labrum, pulvinar, hypertrophied ligamentum teres
    • adductor tenotomy performed if 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 
    • 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 
    • increase anterior or anterolateral coverage
    • used after reduction is confirmed on abduction-internal rotation views and satisfactory ROM has been obtained

Reconstructive Pelvic Osteotomies
 q
Indication
Technique
 
Salter

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.


Triple(Steele)

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

Dega 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.

  
 
 
Complications
  • 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 reduction
      • broadening of 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 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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Questions (12)

(OBQ11.142) Which of the following is true regarding the structure outlined in Figure A? Review Topic

QID:3565
FIGURES:
1

It is comprised of the iliopectineal eminence and quadrilateral surface

22%

(382/1741)

2

In normal hips, all children usually have this radiographic figure by 18 months of age

43%

(746/1741)

3

This figure is usually present in children with developmental dysplasia of the hip prior to reduction

1%

(19/1741)

4

The structure is a result of the radiographic superimposition of the ilioischial and Iliopectineal lines

12%

(214/1741)

5

It is comprised of the cotyloid fossa and iliopectineal eminence

21%

(368/1741)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

The structure outlined in Figure A is the acetabular teardrop and it is comprised of the quadrilateral surface and cotyloid fossa. In normal hips, all children have a teardrop figure by age 18 months of age.

Albicana et al retrospectively reviewed the radiographs of the pelvis and hips of 45 patients who had unilateral congenital dislocation of the hip treated with closed reduction and casting. The width, shape, and type of the teardrop were measured in the dislocated and contralateral, normal hips. They found that the hips with residual acetabular dysplasia had a v-shaped teardrop, widening of the superior width of the teardrop, and thickening of the acetabular floor which correlated with poorer prognosis in adult life.

Bowerman et al identified the structures responsible for teardrop figure by removing sections from the hemipelvis of an anatomic specimen with an electric saw. The normal and abnormal appearances of the teardrop shadow of the acetabulum of three patients were then demonstrated on both plain radiographs and CT scans.

Smith et al reviewed the radiographs of hips with 47 developmental dysplasia (DDH), and 25 normal hips, to determine the timing of the normal appearance of the acetabular teardrop figure and the value of teardrop development after reduction of the hip in predicting outcome. In normal hips, all children had a teardrop figure by age 18 months. In the 47 hips with DDH, no teardrop figure appeared until the hip was reduced. In terms of outcomes, they concluded that the appearance of the acetabular teardrop within 6 months after reduction of the hip is strongly associated with a favorable long-term outcome.


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Question COMMENTS (6)

(OBQ11.187) A 6-week-old female infant is referred to your practice for concerns of developmental dysplasia of the hip. On physical exam, you note a positive Ortolani test on the left side. Pavlik harness treatment is initiated. Which of the following imaging modalities should be utilized at the two week follow-up visit? Review Topic

QID:3610
1

Magnetic Resonance Imaging (MRI)

0%

(5/1468)

2

Computed Tomography (CT)

0%

(5/1468)

3

Ultrasound (US)

96%

(1413/1468)

4

Plain Radiographs

3%

(43/1468)

5

Arthrogram and Dynamic Fluroscopy

0%

(2/1468)

Select Answer to see Preferred Response

PREFERRED RESPONSE 3

Initial ultrasound is performed to confirm reduction of the hip in question (generally after 1 or 2 weeks) followed by repeat ultrasound 6 weeks later. Ultrasound is necessary to avoid leaving an infant in a harness with an unreduced hip which can erode the acetabulum.

Weinstein et al. provide a thorough overview of the presentation, evaluation, and treatment of DDH. The use of office-based ultrasound has helped to confirm hip reduction and proper acetabular development in children being treated with Pavlik harness.

Swaroop and Mubarak performed a retrospective, comparative study looking at children with Ortolani-positive hips who were treated with either Pavlik Harness and education or with Pavlik Harness, serial ultrasound exams, and a hip abduction orthosis upon failure of Pavlik harness. They achieved 93% success in the latter group.

Illustration A shows an illustration of a neonatal hip ultrasound looks like. The alpha angle is illustrated by the blue line which should be greater than 60 degrees in a normal hip. Illustration B demonstrates an ultrasound of a dysplastic hip showing a rounded corner on the lateral acetabular edge (arrow) and a subluxated femoral head. The alpha angle in this hip is approximately 45 degrees. Illustration C demonstrates an ultrasound of a normal hip. Notice the sharp, lateral acetabular edge (arrow) which is consistent with normal hip development and the well-reduced femoral head. The alpha angle here is closer to 65 degrees. Illustration D shows an AP pelvis radiograph showing asymmetric ossification of the proximal femoral epiphysis. An asymmetric lack of ossification (as seen on the left side) should raise suspicion for hip dysplasia.

Incorrect Answers:
Answer 1: MRI requires sedation in patients of this age and is not required as ultrasound can provide the needed information. MR can be useful in confirming closed reduction in older children (6-12 months).
Answer 2: CT exposes the child to unnecessary radiation and is not needed to confirm hip reduction in the harness. CT can be useful in confirming closed reduction in a spica cast.
Answer 4: Plain radiographs can help make the diagnosis of hip dysplasia however they do not provide as much information as ultrasound imaging as the femoral head is not yet ossified in infants.
Answer 5: Arthrogram and fluoroscopy require sedation as well and are more appropriate if a closed reduction in the operating room is required.

ILLUSTRATIONS:

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(OBQ11.235) Which of the following best describes the radiographic measurement labeled #1 on Figure A. Review Topic

QID:3658
FIGURES:
1

Tonnis line

0%

(4/1340)

2

Galeazzi's line

0%

(3/1340)

3

Hilgenreiner's line

1%

(19/1340)

4

Shenton's line

96%

(1285/1340)

5

Perkin's line

2%

(25/1340)

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PREFERRED RESPONSE 4

Radiographic line #1 on Figure A is consistent with Shenton's line.

Developmental dysplasia of the hip (DDH) refers to the the continuum of abnormalities involving the growing hip, (ranging from subluxation to dislocation of the hip joint). Shenton’s line is a projected arc from the inferior border of the femoral neck. Displacement of the femoral head or severe external rotation of the hip will result in a break in the continuity of Shenton’s line.

Guille et al, in a Level 5 article, state that Hilgenreiner’s line is a line drawn horizontally through each triradiate cartilage of the pelvis and Perkins’ line is drawn perpendicular to Hilgenreiner’s line at the lateral edge of the acetabulum. The femoral head should lie within the inferomedial quadrant formed by Hilgenreiner’s and Perkins’ lines.

Illustration A compares the parameters found in a normal and a dysplastic hip.

Incorrect Answers:
1. Tonnis line does not exist. Tonnis angle is an angle formed by a line drawn from point on the lateral triradiate cartilage to point on lateral margin of acetabulum and Hilgenreiners line
2. Galeazzi's line does not exist
3. Hilgenreiner's line is a horizontal line through right and left triradiate cartilage
4. Perkin's line is a perpendicular line to Hilgenreiner's through a point at lateral margin of acetabulum

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Question COMMENTS (1)

(OBQ11.249) A 15-year-old soccer player complains of bilateral hip pain. The pain is worse with activity and she notices that she has fatigue and pain that extends to the thighs and knees following a soccer match. She is nontender at the pubis symphysis and has no pain with resisted abdominal crunches. She has no pain with adduction of the hip. Hip flexion and rotation is normal. A radiograph of the right hip is shown in Figure A. Which of the following surgical interventions is best indicated? Review Topic

QID:3672
FIGURES:
1

Single innominate osteotomy (Salter)

6%

(85/1392)

2

Double innominate osteotomy

2%

(21/1392)

3

Peri-acetabular osteotomy (Ganz)

79%

(1103/1392)

4

Triple innominate osteotomy (Steele)

7%

(95/1392)

5

Dega osteotomy

6%

(82/1392)

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PREFERRED RESPONSE 3

The clinical presentation is consistent with DDH in a patient with a closed triradiate cartilage. A peri-acetabular osteotomy (Ganz) is the most appropriate treatment.

The peri-acetabular osteotomy (Ganz) is a reconstructive osteotomy for DDH patients with a closed triradiate cartilage. It allows for a large degree of three-dimensional correction because the cuts are close to the acetabulum, it preserves the abductor muscles and allows for inspection of the joint.

Karami et al. performed a Level 4 study of 20 patients with an average 12 years of follow-up that underwent a Chiari osteotomy. They found that the Sharp angle, center-edge angle and coverage of the femoral head all improved with the osteotomy but noted that there was a 25% rate of graft resorption.

Gillingham et al., in a level 5 study, emphasizes the timeline of osteotomy indications for DDH patients. A single innominate osteotomy (Salter) or Pemberton procedure is generally appropriate for a child between the ages of 2 and 10. A triple innominate osteotomy (Steel) is applicable for the older child or adolescent where the triradiate cartilage remains open. After triradiate is closed the Ganz periacetabular osteotomy is an option for DDH reconstruction.

Figure A demonstrates a skeletally mature individual with a center-edge angle that is abnormal and less than 20 degrees. Illustrations A-D are examples of the Salter (single nominate) , Ganz (Bernese periacetabular), Steel (Triple Inominate), and Chiari osteotomies, respectively. Illustration E shows a radiograph of the patient in Figure A following a Ganz osteotomy. Illustration F shows a modeling of the bone cuts utilized in a periacetabular osteotomy (Ganz).

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Question COMMENTS (13)

(OBQ10.86) Which of the following concepts regarding pediatric hips is true? Review Topic

QID:3174
1

The proximal femoral physis and greater trochanteric apophysis develop from different cartilaginous physes

25%

(414/1675)

2

The proximal femoral physis grows at a rate of 9 mm per year

2%

(32/1675)

3

Normal infant femoral anteversion is between 10-20 degrees

3%

(50/1675)

4

The ossific nucleus of the proximal femur is visible on radiographs by 6 months of age in most children

62%

(1038/1675)

5

Slipped capital femoral epiphysis (SCFE) typically occurs through the zone of proliferation

8%

(134/1675)

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PREFERRED RESPONSE 4

The ossific nucleus of the proximal femur is visible on radiographs by 6 months of age in most children.

The proximal femoral physis and greater trochanteric apophysis develop from the same cartilage physis in the infant which undergoes apoptotic division in the child. The distal femoral physis (not proximal) grows at a rate of 9 mm per year. The normal infant femoral anteversion is between 30-40 degrees. SCFE typically occurs through the zone of hypertrophy, not the zone of proliferation.

Vitale and Skaggs review the history, diagnosis, treatment, and outcome of developmental dysplasia of the hip.

Wientroub and Gill review the use of ultrasonography in the diagnosis and prognosis of developmental dysplasia of the hip. They recommend detection with ultrasound because of the delayed femoral head ossification (~5 months) and discuss the cost ineffectiveness of routine screening of all newborns.


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Question COMMENTS (6)

(OBQ09.87) Failure to achieve reduction of a dislocated hip in an otherwise healthy 4 month old infant which did not reduce after 3 weeks in a Pavlik harness and 3 weeks in an abduction brace is best treated with which of the following? Review Topic

QID:2900
1

Adjusting the harness to 75 degrees of abduction and maintaing 90 degrees of hip flexion

4%

(40/927)

2

Adjusting the harness to 75 degrees of abduction and increasing hip flexion to 120 degrees

2%

(17/927)

3

Closed reduction with hip arthrogram, adductor tenotomy if necessary, and hip spica casting

92%

(849/927)

4

Open reduction and femoral shortening osteotomy

1%

(7/927)

5

Open reduction, femoral shortening osteotomy, and pelvic acetabular osteotomy

1%

(9/927)

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PREFERRED RESPONSE 3

A 4-month-old who fails Pavlik harness treatment is best treated with closed versus open reduction of the hip and spica casting. Continued harness treatment can be detrimental as there is risk of posterior acetabular erosion. Osteotomies are not necessary to achieve reduction in a patient of this age cohort.

In the review by Guille et al, he reports unsuccessful treatment of DDH with Pavlik Harness treatment if the hip does not become reduced within 2 weeks of treatment and recommends transitioning to alternative treatment options.

Mubarak, et al reports 12 failures in 18 infants with hip dislocations due to improper physician technique and/or inappropriate harness. Failure to recognize inadequate reduction portends worse clinical outcomes. Another option for failed Pavlik harness treatment in infants is a hip abduction brace.

Hedequist reports on 13 of 15 patients who failed Pavlik harness treatment, and went on to resolve DDH with an abduction brace avoiding the operating room and anesthesia for a closed reduction and spica casting.


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Question COMMENTS (8)

(OBQ08.42) A 2-week-old infant girl is referred for a hip clunk noticed by the pediatrician. She has a history of a normal spontaneous vaginal delivery and is otherwise healthy. Examination demonstrates a right hip Ortolani sign. A coronal ultrasound is shown in figure A. What is the most appropriate next step in treatment? Review Topic

QID:428
FIGURES:
1

Observation with repeat ultrasound in 1 month

11%

(135/1207)

2

Pavlik harness application

86%

(1038/1207)

3

Closed reduction and spica casting

2%

(23/1207)

4

Open reduction and spica casting

0%

(4/1207)

5

Open reduction, acetabular osteotomy, femoral shortening, and spica casting

0%

(0/1207)

Select Answer to see Preferred Response

PREFERRED RESPONSE 2

This patient has a right hip dislocation (DDH), as demonstrated by the positive Ortolani sign. Pavlik harness application is indicated for treatment. If the hip does not stay reduced within a few weeks, the next option is an arthrogram under anesthesia, closed reduction, and spica casting. Open reduction and casting is reserved for when closed reduction has failed. Acetabular osteotomy and femoral shortening are procedures used for children with DDH typically older than 1.5 years.


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(OBQ08.150) In patients older than 12-months of age with developmental dysplasia of the hip, all of the following physical exam findings are likely present EXCEPT? Review Topic

QID:536
1

Limited hip abduction

3%

(22/872)

2

Positive Ortolani maneuver

83%

(721/872)

3

Abnormal leg lengths on Galeazzi testing

2%

(21/872)

4

Trendelenburg gait

7%

(64/872)

5

Pelvic obliquity

5%

(42/872)

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PREFERRED RESPONSE 2

There are many exam maneuvers which are used in the diagnosis of developmental dysplasia of the hip (DDH). Exam findings differ based on the age of the patient.

Vitale et al emphasize that physical exam findings associated with DDH in a child older than 12-months can be different than those seen in the newborn. Specifically, limited hip abduction, a positive Galeazzi test, a positive Trendelenburg gait, and asymmetry of hip abduction are all useful exams tests that are likely to be positive. The Barlow and Ortolani maneuvers are of limited use in older children (> 6 months) because the soft tissues about the hip tighten.

Illustration V demonstrate how the Barlow and Ortolani test are performed.

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(SBQ07.100) Figures A-E show a series of radiographic lines used in the assessment of a paediatric hip joint. Which of the following figures shows Perkin's line? Review Topic

QID:1585
FIGURES:
1

Figure A

78%

(2168/2795)

2

Figure B

12%

(340/2795)

3

Figure C

4%

(100/2795)

4

Figure D

3%

(84/2795)

5

Figure E

3%

(92/2795)

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PREFERRED RESPONSE 1

Figures A-E show a series of radiographic lines that overlay an AP pelvis x-ray of a patient with developmental dysplasia of the hip (DDH). Figure A shows Perkin's line.

Perkins line is used in the assessment of developmental dysplasia of the hip (DDH). It is a radiographic line drawn perpendicular to Hilgenreiner's line (Figure B) that intersects the most lateral aspect of the acetabular roof through the anterior inferior iliac spine. In the normal hip, the femoral head should be medial to Perkins line. The femoral head may be lateral to Perkins line in the setting of a hip dislocation.

Guille et al. reviewed the assessment and management of DDH in infants less than 6 months. They showed that plain radiographs are not useful in the first 6 months of life due to the lack of femoral head ossification for reliable estimation of position.

Weinstein et al. looked at the factors of contributing to DDH. The reported risk factors for DDH include: breech presentation (25% risk), family history (6-20%), foot deformities (2%), congenital torticollis (10-20%), skull-molding deformities (5-10%).

Illustration A is a diagram showing acetabular index angle, Hilgenreiner's line, Shenton's line, and Perkin's line

Incorrect Answers:
Answers 2: Figure B shows an AP radiograph of the hip with Hilgenreiner's line. This is a line connecting the superolateral margins of the triradiate cartilage. The femoral head is often migrated superior to this line in DDH.
Answer 3: Figure C shows an AP radiograph of the hip with Shenton's line. This is a line formed by the inferior surface of the superior pubic ramus and the medial surface of the proximal femoral metaphysis at the level of the lesser trochanter. In a normal hip it should create a smooth, curved line. In DDH it is often disrupted.
Answer 4: Figure D shows an AP radiograph of the hip with acetabular angle/index. This line represents the slope of the acetabular roof. It helps measure the angle between Hilgenreiner's line and the acetabulum. DDH usually has an increased angle, which does not improve unless the hip is reduced.
Answer 5: Figure E shows an an AP radiograph of the hip with Klein's line. It is used for the assessment of a slipped capital femoral epiphysis.

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(OBQ05.83) In infants with developmental dysplasia of the hip (DDH), anatomic closed reduction may be prevented by all of the following anatomic structure EXCEPT. Review Topic

QID:969
1

Interposition of gluteus medius

87%

(875/1002)

2

Limbus formed by fibrous tissue and hyaline cartilage

3%

(27/1002)

3

Ligamentum teres and prominent fibrofatty pulvinar tissue

2%

(21/1002)

4

Contracted transverse acetabular ligament

5%

(53/1002)

5

Inverted acetabular labrum

2%

(22/1002)

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PREFERRED RESPONSE 1

Interposition of gluteus medius is not associated with blocked reduction in patients with DDH.

The review article by Guille et al reviews the soft-tissue adaptations in DDH, and discusses the various blocks to reduction which include:

Answer 2: Fibrous tissue can merge with the hyaline cartilage of the acetabulum rim forming the limbus, which may then prevent concentric reduction of the hip.

Answer 3: The ligamentum teres and fibrofatty tissue, known as the pulvinar, may be found within the depths of the acetabulum and can also be an obstacle to reduction and are both depicted by the black arrows in Illustration B.

Answer 4: The transverse acetabular ligament at the caudal aspect of the acetabulum, contracts in patients with persistent hip dislocation and is a block to concentric reduction of the hip.

Answer 5: In the older infant with DDH, the acetabular labrum may be inverted and may mechanically block concentric reduction of the hip.

In addition, with long-standing dislocation, the stretched hip capsule becomes constricted by the contracted iliopsoas tendon to assume an hourglass configuration that prevents reduction as shown in Illustration A by the arrows.

Illustration C depicts the anatomy of these barriers to reduction in DDH.

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(OBQ04.175) A five-year-old boy with cerebral palsy presents to the clinic with a dislocated right hip, what quadrant of the acetabulum is most likely deficient? Review Topic

QID:1280
1

Anterior-inferior

2%

(14/857)

2

Anterior-superior

16%

(139/857)

3

Posterior-superior

76%

(648/857)

4

Posterior-inferior

5%

(45/857)

5

Anterior-inferior and anterior-superior

1%

(8/857)

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PREFERRED RESPONSE 3

In patients with cerebral palsy, the hip is normal at birth, but a combination of muscle imbalance and bony deformity leads to progressive hip dysplasia. The review article by Flynn notes that spasticity or contracture usually involves the adductor and iliopsoas muscles. Because of the pull of these muscles, the majority of hips subluxate in the posterosuperior direction. Because physical examination is unreliable, an AP of the pelvis is required for diagnosis.


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(OBQ04.215) Figure A depicts an ultrasound of a newborn infant's hip. Which of the following structures (1 through 5) represents the labrum? Review Topic

QID:1320
FIGURES:
1

1

2%

(6/391)

2

2

0%

(0/391)

3

3

20%

(79/391)

4

4

75%

(293/391)

5

5

3%

(10/391)

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PREFERRED RESPONSE 4

Figure A depicts an ultrasound of a newborn infant, which is routinely used in the screening and monitoring for hip dysplasia. The structure labeled by the number 4 is the labrum.

Harke et al reviewed the management of congenital dislocation and dysplasia of the hip and the role of ultrasound (US). They concluded that US has distinct advantages over clinical and radiographic examination. As a “novel” technique for evaluation of infant hip dysplasia in 1991, they hoped US would provide a tool for screening and studying the natural history of the developmental disorders of the hip. Since that time, ultrasound has become very helpful in the evaluation of newborn and infant hips as the ossific nucleus of the femoral head is not visible on radiographs.

Illustration A depicts an ultrasound with structures abbreviated. Illustration B is a cartoon schematic of the hip. Il:ilium, Ac:acetabulum, L:labrum, G:gluteal muscles, C:capsule, GT:greater trochanter, H:femoral head, LT/P:ligamentum teres/pulvinar, Tr: triradiate cartilage.

Incorrect Answers:
Answer 1. Ilium is labeled is by the number 1
Answer 2. Femoral head is labeled is by the number 2
Answer 3. Triradiate cartilage is labeled by the number 3
Answer 5. Ischium is labeled by the number 5

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