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Developmental Dislocation of the Hips
Dr David Little



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Developmental Dislocation of the Hips
Table of Contents
  • Definitions
  • Incidence
  • Aetiology
  • Screening
  • Late Presentation
  • Pathologic Anatomy
  • Natural History
  • Diagnosis
  • Primary Treatment
  • Secondary Treatment
  • Summary

    • Definitions
    Incidence
    Aetiology
    Screening
    Late Presentation
    Diagnosis
    Radiology
    Neonatal Management
    Treatment at 6 months to 2 years
    Treatment after 2 years
    Complications of Primary Treatment
    Secondary Treatment
    Summary

    Definitions

     DDH refers to any manifestation of instability, dysplasia, or dislocation

    • Dislocated
    • Dislocatable
    • Subluxatable
    • Dysplasia
    • Not Teratologic / Neurogenic

    Incidence

    • Females 1:600
    • Males 1:4000
    • Overall 1:1-2000 (Dislocation)
    • Dysplasia 7.5/1,000 (S.Aust)
    • Depends on definition, 58% resolve without treatment (Barlow)

    Aetiology
    Unknown for certain
    Balance between ligamentous laxity, maternal hormones, and positional factors.
    There is also some undefined genetic factor (?laxity also)
     

    Definite risk factors

    • Female sex
    • Family history
    • (Ligamentous Laxity)
    • Breech positioning
    • Infantile muscular torticollis
    • Postnatal positioning Prematurity seems protective

    Ligamentous Laxity

    Maternal hormones around time of delivery increase laxity in neonate
    Female rabbits splinted in extension and given progesterone dislocate their hips, males dont
    75% of boys and 33% of girls with DDH have hyperlaxity

    Positional Factors - Prenatal

    • Frank breech 20% incidence of DDH
    • Footling breech 2%
    • Normal vaginal delivery 0.7% (Suzuki)
      If have LSCS still at risk
    • Congenital muscular torticollis may be due to positioning and a rough birth 20% incidence of DDH with torticollis (MacEwen)
    • Metatarsus adductus (packaging defect) 1.5% -10% incidence
    • No association with CTEV (not a packaging defect)

    Positional Factors - Postnatal positioning

    Rare in India where babies carried in wide abduction
    High in American Indians and Eskimos where babies placed on cradle board with hips extended for prolonged periods
    Klisic reduced DDH by 65% in Belgrade by routine use of abduction diapering
    ?recent increase with side lying for SIDS

    Genetic Factors

    • Identical twin risk 34%
    • Fraternal twins risk 3%
    • 2.2% of siblings affected
    • 1.3% of parents affected
    ?Primary acetabular dysplasia
    ?Familial ligamentous laxity

    Screening

    Good results
    Hadlow (NZ) missed 2 / 20 657 screened
    Treadwell (Vancouver) missed 4 / 120 000
    Poor results
    Late presentation increased after screening
    Catford and Wilkinson (Southampton)
    Lennox (Aberdeen)
    Depends on personnel, organisation Screening
    • Should continue in best form possible as there is no doubt of the value of finding and treating neonatal cases
    • Ultrasound will eventually have pivotal role once cost and availability logistics are sorted out
    • Concept of screening only those at risk

    Late Presentation

    40% of those presenting late to RAHC have major risk factor (breech or FHx)

    Morbidity higher and results poorer after walking age

    Concept of surveilance to diagnose late cases < 1yr

    multiple and repeated examination

    Pathologic Anatomy

    Initial stage

    • Minimal anatomic changes
    • Laxity of lateral joint capsule
    • Blunting of labrum
    • Neolimbus (mound of cartilage)
    • No muscle contractures
    • Hip reducible
    Later

    • Hip irreducible
    • Capsular contracture medially and narrowing at isthmus
    • Hypertrophy of ligamentum teres
    • Hypertrophy of pulvinar
    • Inverted labrum usually iatrogenic
    • Contracted adductors and psoas

    Natural History

    Short Term Natural History

    • Established dislocation at birth rare
    • Many reduce and become stable (Barlow 58% spontaneously resolved with no treatment)
    • Some become dysplastic and subluxated
    • Others dysplastic and dislocated
    • Minimal disability

    Long Term Natural History

    • Dysplastic hips become arthritic at 20 year follow up (worse than dislocated)
    • Subluxation heralds the onset of OA
    • Complete dislocation does not produce disability until the 5th decade of life
    • Worse if false acetabulum forms
    • Knee pain and low back pain variable

    Diagnosis

    History

    Breech positioning
    Family history
    Ligamentous Laxity
    • Infantile muscular torticollis
    • Postnatal positioning
    • Walking age
    • Gait abnormality

    Examination

    Examination of Neonate

    Look

    • Skin creases
    • Galeazzi
    Feel

    • Trochanter / ASIS
    Move

    • Ortolani No force required
    • Barlow

    Examination of Older Child

    Look

    • Skin creases
    • Galeazzi
    Feel

    • Trochanter / ASIS
    Move

    • Limited abduction

    Examination of Walking Child

    Look

    • Hip flexion contracture / Lumbar Lordosis
    • Walks on one toe or with long knee bent
    • Trendelenberg
    Feel

    • Trochanter / ASIS
    Move

    • Limited abduction

    Radiology

    Radiographs

    Not useful for neonates
    Classic descriptions of plain radiographic findings very limited
    Older children
    Acetabular index < 5 yrs
    CE angle > 5 yrs

    Ultrasound

    Useful tool in neonate

    Static (Graf)
    Dynamic (Harcke)

    Gestalt

    Follow development in Pavlik

    Arthrography

    Mainstay of imaging for intraoperative decisions still
    Assess closed reduction
    Decide on need for open reduction
    Dye in joint makes post op film interpretation possible in spica

    CT Scanning / MRI

    Confirm reduction maintenance in spica
    Not routinely necessary
    Some recommend it at 2 weeks so that you don't leave a hip out in a spica for 6 weeks

    3 D CT Scanning

    Picture acetabular dysplasia
    Do appropriate coverage procedure
    No study to show this approach alters outcome of routinely doing a Salter for dysplasia on plain film

    Primary Treatment

    Neonatal Management

    Goals

    Reduction
    Acetabular development
    Minimal negative effects
    Flexion and minimal abduction

    Cartilagenous head vulnerable to wide abduction

    Neonatal Management

    • Pavlik Harness
    • Von Rosen Splint
    • Frejka Pillow
    • Denis Browne Splint
    All good results

    ? High AVN rate in Frejka

    Pavlik Harness

    Any child less than 6 months
    Full time until stable (often rapid)
    Six weeks after stability achieved
    ?Value of weaning
    Positioning important
    See child at 2nd weekly until stable, monthly until dysplasia resolves Complications avoidable
    Femoral n palsy (hyperflexion)
    AVN (hyperabduction)
    Posterior dysplasia (too long in harness without reduction) If hip not reduced in 3 - 4 weeks discontinue and go to closed reduction

    Treatment at 6 Months to 2 Years

    Traction

    Impossible to work out if necessary
    95% of North American Orthopaedists use traction

    Closed reduction / Arthrogram

    No force required
    Spica cast minimum 3 months in HUMAN POSITION
    • Failed Closed Reduction
      Irreducible
      Reduces but only stable in extreme position
       
    • Poor arthrographic findings
    Medial pooling
    Blunted labrum

    Open Reduction

    Antero-medial or Medial

    Divide Adductor Longus and Psoas
    Preserve medial circumflex vessels
    Medial capsulotomy
    Transverse ligament divided
    Ligamentum Teres excision
    Pulvinar removed
    Capsulorrhaphy or pelvic osteotomy not possible
     

    Anterior (Modified Smith-Petersen)

    Interval between TFL and Sartorius
    Preserve Lateral Cutaneous Nerve
    Divide Rectus Femoris
    T capsulotomy
    Remove obstacles
    Capsulorrhaphy (v. important in older children)

    Treatment after 2 years

    Closed reduction not possible or wise

    Anterior open reduction

    + femoral shortening
    + pelvic osteotomy Bilateral hips done sequentially
    6 weeks apart
    Months apart

    Complications of Primary Treatment

    AVN

    Most feared as untreatable
    Many appear as late partial arrests
    Redislocation

    Must be prepared for this contingency
    Outcome still very good if recognised early
    Dysplasia

    Follow up long term required

    Secondary Treatment

    Concentric reduction reverses

    • shallow acetabulum
    • anteversion of acetabulum
    • anteversion of femur
    Improvement goes on until ~8 years

    Recent work shows though improvement occurs may never be normal

    Indications

    • Staheli Acetab angle >24o at 24 mo
    • Herring Failure to improve over 2 years
    • Coleman Failure to improve or subluxation
    • Lindstrom Still dysplastic at age 8
    Dysplastic hips fare poorly

    Procedures are reliably effective

    Prerequisites

    Concentric reduction
    Reducible subluxation
    Must do open reduction if not reducible
    Chosen procedure will be adequate (AIR film)

    Femoral Osteotomy

    • Varus Producing
    • Varus resolves in young children
    • Best results < age 4
    • Moderate results 4-8
    • Poor results > age 8
    • Relies on femur to induce acetabular remodeling

    Pelvic Osteotomy

    Salter Redirectional Salter results excellent (normal hips)
    Pemberto Redirectional Pemberton results also excellent
    Dega Acetabuloplasty
    Steele (Sutherland) Redirectional Steele results good short term
    Dial Redirectional
    Chiari 2o Coverage buy time
    Shelf 2o Coverage buy time

    Arthrodesis

    Only necessary for completely destroyed hip
    Not until skeletal maturity

    Total Hip Arthroplasty

    Good short term results
    Multiple revisions

    Summary

    Natural history known

    Treatment is improvement on natural history

    Success based on effective early treatment and avoidance of complications

    Late presentations still occur

    by Dr David G Little,
    Paediatric Orthopaedic Surgeon
    New Children's Hospital, Westmead NSW
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    This page was last built on 23/1/99; 13:19:37.
    It was originally posted on 12/4/98; 8:40:28.
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