Fractures and Dislocations about the Knee in Pediatric Patients

1
Fractures and Dislocations about the Knee in
Pediatric Patients

• Steven Frick, MD
• Created March 2004 Revised August 2006

2
Anatomy

• Distal femoral physis- large, undulating-
  irregular
• Proximal tibial physis- contiguous with tibial
  tubercle apophysis
• Ligament and muscular attachments may lead to
  avulsion injuries, fracture angulation

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Anatomy- Neurologic and Vascular Structures

• Popliteal artery tethered above and below knee
• Common peroneal nerve vulnerable at fibular
  neck/head

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Growth about the Knee

• 70 of lower extremity length
• Distal femur- average 10mm/year
• Proximal tibia- average 6mm/year
• Tibial tubercle apophysis- premature growth
  arrest can lead to recurvatum
• Proximal fibular physis- important for fibular
  growth relative to tibia and ankle alignment

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Fractures of the Distal Femoral and the Proximal
Tibial Physis

• Account for only a small percentage of the total
  number of physeal fractures
• Are responsible for the majority of complications
  due to partial physeal arrest
• High incidence of growth arrest based on anatomy,
  energy of injuries
• Specific treatment recommendations to minimize
  the incidence of growth arrest

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Peterson, et.al. JOP 94 Olmstead County Study

• Experience of the Mayo clinic 1979 - 1988
• 951 physeal fractures
• 2.2 involved the physis of the distal femur or
  the proximal tibia
• Fractures of the distal femoral and proximal
  tibial physis account for 51 of partial growth
  plate arrest

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Anatomy Predisposingto Growth Arrest

• Peterson 94 noted that the distal femoral and
  proximal tibial physes are large and multiplanar
  (irregular in contour) and account for 70 and 60
  of the growth of their respective bones

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Anatomy, continued

• Ogden, JOP 82 - undulations of the physis,
  which may include small mammillary processes
  extending into the metaphysis, or larger curves
  such as the quadrinodal contour of the distal
  femoral physis, may cause propagation of the
  fracture into regions of the germinal and resting
  zones of the physis

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Anatomy, continued

• Ogden JPO, 82 - distal femur develops binodal
  curves in coronal and sagital planes with central
  conical region - susceptible to damage during
  varus/valgus injury
• Peripheral growth arrest related to damage to
  zone of Ranvier stripping it away from physis and
  periosteum

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Distal Femoral Physeal Fractures

• direct blow mechanism
• Salter I or II common
• check neurologic / vascular status

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Treatment Recommendations

• Anatomic reduction is key
• Propensity for losing reduction
• Hold reduction with pins and casting

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Thompson et.al. JPO 95

• 30 consecutive fractures of the distal femoral
  epiphysis
• No displacement of fx treated with anatomic
  reduction and pin fixation
• Three of seven patients treated closed lost
  reduction
• proved maintenance of reduction, but not
  prevention of growth disturbances

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Graham Gross, CORR 90

• Ten patients with distal femoral physeal
  fractures retrospectively reviewed
• All treated from 77 - 87 with closed reduction
  and casting or skeletal traction
• Most SHII
• Resulted in seven losing reduction and nine
  eventually developing deformities

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Graham Gross cont.

• Angular deformity and LLD related to the amount
  of initial deformity and the quality of reduction
• Recommended rigid internal fixation

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Riseborough, et.al., JBJS 83

• Retrospective study of 66 distal femoral physeal
  fracture-separations
• Only 16 seen primarily, others referred at
  different stages of treatment/complications
• Noted improved results with anatomic reduction
  and internal fixation in types II,III and IV, and
  early detection and mgmnt of growth arrest

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Lombardo Harvey, JBJS 77

• 34 distal femoral physeal fx. Followed avg. four
  years
• gt2cm LLD in 36
• Varus/valgus deformity in 33
• Osteotomy, epiphyseodesis or both in 20
• Development of deformity related to amount of
  initial displacement and anatomic reduction
  rather than fracture type

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Be Wary of Fixation only in Thurston-Holland
Fragment
Loss of reduction at 2 weeks
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Distal Femoral Physeal Fractures

• closed reduction and pinning for displaced
  fractures
• long leg cast

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Distal Femoral Physeal Fractures

• high rate of premature growth arrest rare lt 2
  yo 80 2 - 11 yo 50 gt 11 yo
• angular deformity
• leg length discrepancy

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Salter IV Distal Femur Fracture Lateral Growth
Arrest led toValgus Deformity
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Salter IV Distal Femur Fracture
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Distal Femur Physeal Bar
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Patella Fractures in Children

• Largest sesamoid bone, gives extensor mechanism
  improved lever arm
• Uncommon fracture in skeletally immature patients
• May have bipartite (superolateral) patella- avoid
  misdiagnosis

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Physeal Bars

• male female - 2 1
• distal femur, distal tibia, proximal tibia,
  distal radius

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Valgus deformity, short limb following distal
femur SII fx with growth arrest, failed bar
excision
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Distal osteotomy first to correct alignment, then
lengthening over nail to restore length
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Patellar Sleeve Fracture

• 8-12 year old
• Inferior pole sleeve of cartilage may displace
• May have small ossified portion
• lt2mm displaced, intact extensor mechanism- treat
  non-operatively

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Patella Fractures

• much less common than adults
• avulsion mechanism
• patellar sleeve fracture
• management same as adults
• Restore articular surface and knee extensor
  mechanism

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Osteochondral Fractures

• Usually secondary to patellar dislocation
• Off medial patella or lateral femoral condyle
• Size often under appreciated on plain films
• Arthroscopic excision vs. open repair if large

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Acute Hemarthrosis in Children-without Obvious
Fracture

• Anterior Cruciate Tear
• Meniscal tear
• Patellar dislocation /- osteochondral fracture

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Knee InjuriesAcute Hemarthrosis

• ACL 50
• Meniscal tear 40
• Fracture 10

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Tibial Eminence Fractures

• Usually 8-14 year old children
• Mechanism- hypertension or direct blow to flexed
  knee
• Frequently mechanism is fall from bicycle

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Myers- McKeever Classification

• Type I- nondisplaced
• Type II- hinged with posterior attachment
• Type III- complete, displaced

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Tibial Eminence Fracture- Treatment

• Attempt reduction with hypertension
• Above knee cast immobilization
• Operative treatment for block to extension,
  displacement, entrapped meniscus
• Arthroscopic-assisted versus open arthrotomy
• Consider more aggressive treatment in patients 12
  and older

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Tibial Spine Fracture

• 8 to 14 yo
• often bicycle accident
• Myer-McKeever classification

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Tibial Spine FractureTreatment

• Reduction in extension
• Immobilize in extension or slight knee flexion
• Operative treatment for failed reduction or
  extension block

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Tibial Spine Closed Reduction
Follow closely get full extension
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Tibial Spine Malunion-Loss of Extension
Injury Film no reduction
2 years post-injury- lacks extension
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Tibial Spine Fx- Arthroscopic OR,Suture Fixation
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Tibial Eminence Fracture- Results

• Generally good if full knee extension regained
• Most have residual objective ACL laxity
  regardless of treatment technique
• Most do not have symptomatic instability and can
  return to sport

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Tibial Tubercle Fractures

• Primary insertion of patellar tendon into
  secondary ossification center of proximal tibia
• Mechanism- jumping or landing, quadriceps
  resisted contraction
• Common just before completion of growth (around
  15 years in males)

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Tibial Tubercle Fracture Classification- Ogden

• Type I- fracture through secondary ossification
  center
• Type II- fracture at junction of primary
  secondary ossification centers
• Type III- fracture extends into primary
  ossification center, intraarticular

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Tibial Tubercle Fractures- Treatment

• Nondisplaced, intact extensor mechanism- above
  knee immobilization for 6 weeks in extension
• Displaced, loss of extensor mechanism integrity-
  operative fixation

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Tibial Tubercle Fracture

• 10 - 14 year old
• often during basketball
• surgery for displaced fractures, inability to
  extend knee

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Proximal Tibial Physeal Fractures

• Usually Salter II fractures.
• Occasionally Salter I or IV
• Posterior displacement of epiphysis or metaphysis
  can cause vascular compromise

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Proximal Tibia Fracture
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Proximal Tibial Physeal Fractures- Salter I or II

• Often hyperextension mechanism
• Thus flexion needed to reduce
• If unstable fracture or hyperflexion needed to
  maintain reduction, use percutaneous fixation
• Above knee cast for 6 weeks

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Proximal Tibia Salter I Fracture
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Proximal Tibia Physeal Fractures

• Open reduction for irreducible Salter I and II,
  displaced Salter IV
• Observe closely for vascular compromise or
  compartment syndrome in first 24 hours
• Follow for growth disturbance, angular deformity

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Complications

• angular deformity
• malunion
• physeal bar
• leg length discrepancy

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Proximal Tibial Metaphyseal Fractures

• Younger patients, less than 6 years
• Often nondisplaced, nonangulated
• Later progressive valgus deformity can result
  from medial tibial overgrowth (Cozen Phenomenon)

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Proximal Tibial Metaphyseal Fractures

• Initial treatment- try to mold into varus to
  close any medial fracture gap
• Notify parents initially of possible valgus
  deformity development
• Follow 2-4 years

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Valgus Deformity after Proximal Tibial
Metaphyseal Fracture

• Observe, do not rush to corrective osteotomy
• Typically remodels, may take years
• Not all will remodel
• Consider staple epiphyseodesis, osteotomy if
  severe

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Genu Valgum following Proximal Tibia Metaphyseal
Fracture
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Valgus after Proximal Tibia fx
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Proximal Tibia Metaphyseal fx, Displaced- Often
Young Child, High Energy
Careful assessment of distal perfusion necessary,
monitor for compartment syndrome
3 yo boy
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Patellar Dislocations

• Almost always lateral
• Younger age at initial dislocation, increased
  risk of recurrent dislocation
• Often reduce spontaneously with knee extension
  and present with hemarthrosis
• Immobilize in extension for 4 weeks

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Patellar DislocationNote Medial Avulsion off
Patella and Laxity in Medial Retinaculum
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Patellar Dislocations

• Predisposing factors to recurrence- ligamentous
  laxity, increased genu valgum, torsional
  malalignment
• Consider surgical treatment for recurrent
  dislocation/subluxation if fail extensive
  rehabilitation/exercises

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Lateral Patellar Dislocation
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Knee Dislocations

• Unusual in children
• More common in older teenagers
• Indicator of severe trauma
• Evaluate for possible vascular injury
• Usually require operative treatment capsular
  repair, ligamentous reconstruction

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