Pediatric Knee Injuries
Greg M. Osgood, MD
Revised 2011
Additional images courtesy of Paul Sponseller, MD and Arabella Leet, MD
First edition by Steven Frick, MD
Significance
LE growth:
– Distal femur: 10mm / yr
– Proximal tibia: 6mm / yr
– Tibia tubercle growth arrest can lead to recurvatum
Fractures of the distal femoral and proximal
tibial physis account for 2.2% of physeal
fractures BUT they account for 51% of partial
growth plate arrest
Peterson HA, et al. JPO 1994;14(4):423.
Overview
Extra-articular injuries
Intra-articular injuries
Overview
Extra-articular Knee Injuries
– Distal Femoral Epiphysis
– Proximal Tibia Epiphysis
– Tibia Tubercle
– Patella
Overview
Intra-articular Knee Injuries
– Tibial Eminence Fractures
– Osteochondral Fractures
– Patella Dislocation
– Menicus Injuries
– Ligament Injuries
Distal Femoral Epiphyseal Fractures
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Anatomy
– Distal femoral physis contributes 70% of
femoral growth and 37% of lower extremity
length
– Popliteal artery and geniculates lie posterior to
metaphysis and capsule
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Fracture Epidemiology
– Rare injury (<1% of pediatric fractures)
– Mechanism:
• Often the result of high energy trauma in <11 y.o. (pedestrian struck or
fall from a height)
• Sports injuries in teens (2/3 of distal femoral fractures)
• varus/valgus force
• hyperextension of the knee
Associated Injuries
– Do not miss VASCULAR INJURY or TIBIAL/PERONEAL
NERVE INJURY
– Do not miss COMPARTMENT SYNDROME
Riseborough EJ, et al. JBJS(A) 1983;65:885.
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Physical Examination
– Pain
– Inability to bear weight
– Obvious deformity
– Swelling and
ecchymosis
– Anterior displacement
may be associated with
vascular injury
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Associated Injuries
– Knee ligament injury (8-43% incidence)
• Requires close follow-up of knee stability as fracture heals
• Repair at time of other intra-articular repair
– Vascular Injury
• May be associated with anterior fracture displacement
• Remember pulseless limb may regain normal pulses after fracture
reduction and splinting
• Revascularization should be coordinated with vascular surgery team if
necessary
– Nerve Injury
• Peroneal injury rare
• Observation at least 3 months is indicated, followed by EMG if symptoms
persist
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Radiographs
– AP & LAT xrays
– Valgus or Varus Deformity Common
– Rarely Anterior Displacement
– Oblique views may be necessary
– Comparison contralateral xrays
• (expecially in infants – consider USG)
– Consider stress xrays
– CT may help evaluate fracture complexity
– MRI
Classification
– Salter-Harris (I and II most common)
– Displacement (anterior, posterior, valgus/varus)
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Interventions
– Closed reduction and immobilization
– Closed reduction and internal fixation
– ORIF
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Closed Reduction and Casting
– Used only in truly nondisplaced and stable
fractures
– Anatomical reduction is more important close to
age of skeletal maturity
– Remodeling potential is greatest in plane of knee
motion (flexion/extension)
– Discuss potential for growth disturbance or
malalignment with family when treatment is
initiated
– Frequent follow-up is required to prevent malunion
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Closed Reduction and Casting
– Closed reduction usually successful within 10
days
– Well molded splint in slight knee flexion
– Periosteum is often intact on compression side
of fracture – compression side of fracture
should be put under tension in splint/cast
– Partial WB started at 2-3 weeks
– Splint/cast removal between 4-8 weeks
Thomson J. JPO 1995;15:474.
Graham JM.–
CORR
1990;255:51.
43-70%
displace without internal fixation
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Closed Reduction and Internal
Fixation
– Reduction performed with
TRACTION and angular correction
– Fixation should not cross physis if
possible
• Screws may be placed parallel to
physis at the metaphysis (Salter II &
IV) or epiphysis (Salter III & IV)
– Use smooth pins to cross physis if
necessary
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Open Reduction and
Internal Fixation
– INDICATIONS
• Fractures that cannot be
satisfactorily reduced closed
• Salter III and IV fractures
• Open fractures
• Floating knee
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Open Reduction and Internal Fixation
– Preoperative CT may help plan fixation strategy
– Reduction facilitated by removal of interposed muscle
and periosteum
– Fixation parallel to physis
– Cross physis with smooth wire fixation only if
necessary to obtain stability
– Support fixation with postop splint or cast
– Repair associated collateral ligament injuries at time of
fixation if possible
– Remove pins at 3-6 weeks
– Remove splint at 6-8 weeks
Salter IV Distal Femur Fracture
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Open Reduction and Internal Fixation
– Plates spanning across growth plate should be
avoided unless patient is at skeletal maturity
– Skeletal maturity is often difficult to assess and
is easily overestimated
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Complications of Injury
– Ligamentous laxity
– Knee stiffness
– Compartment syndrome
– Malalignment
– Shortening
– Loss of reduction
Extra-articular Knee Injuries
Distal Femoral Epiphysis
SH II Fx
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Extra-articular Knee Injuries
Distal Femoral Epiphysis
6 mo postop
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Extra-articular Knee Injuries
Distal Femoral Epiphysis
SH IV FX with distal metaphyseal femur fx
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Outcomes
– Risk of damage to growth plate and growth
disturbance
• Assess leg length, alignment and gait at 6 months
• Follow patients 12-24 months
• Growth disturbance caused by direct trauma or lack
of anatomical reduction
• Transphyseal bridging may be demonstrated on MRI
Distal Femur Physeal Bar
Valgus deformity, short limb following
distal femur SII fx with growth arrest,
failed bar excision
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Severe growth plate injury 9 years after SH II
distal femoral physeal injury in 4 y.o. girl
Proximal Tibial Epiphyseal Fractures
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Fracture Epidemiology
– Rare injury (<1% of pediatric fractures)
– Mechanism:
• Often the result of high energy trauma (MVC or fall
from a height)
• varus/valgus force
• hyperextension of the knee
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Physical Examination
– Pain
– Knee effusion/hemarthrosis
– Tenderness at physis
– Limb deformity
– Document pulse and neurological examination before
and after reduction
Associated Injuries
– Do not miss VASCULAR INJURY or
TIBIAL/PERONEAL NERVE INJURY
– Do not miss COMPARTMENT SYNDROME
Extra-articular Knee Injuries
Distal Femoral Epiphysis
Associated Injuries
– Knee ligament injury
• Requires close follow-up of knee stability as fracture heals
– Vascular Injury
• May be associated with posterior displacement of metaphysis
• Remember pulseless limb may regain normal pulses after
fracture reduction and splinting
• Revascularization should be coordinated with vascular surgery
team if necessary
– Compartment Syndrome
• Tethering of popliteal artery, posterior tibial artery, and
anterior tibial artery place limb at compartment syndrome risk
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Radiographs
– AP & LAT xrays
– Frequently minimally displaced & easily
overlooked
– Stress xrays may help
– CT may help assess possible Salter III or IV
– MRI
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Intervention
– Closed reduction and immobilization
– Closed reduction and internal fixation
– ORIF
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Closed Reduction and Casting
– Indicated in non-displaced fractures
– Possible if stable anatomical reduction achieved
with Salter I and II fractures
– TRACTION is key to reduction
– Monitor for iatrogenic peroneal injury after
reduction
– Splint/cast (bivalved) reduction in slight knee
flexion
– Cast may be removed 6 weeks after injury once
radiographic evidence of healing
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Closed Reduction and Internal Fixation
– Indicated if UNSTABLE reduction is achieved
in Salter I and II fractures
– Percutaneous fixation parallel to physis
– Crossed pins that traverse the physis may be
used if stable extra-physeal fixation is not
possible
– Splint reduction in slight knee flexion
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Open Reduction and Internal Fixation
– Indications:
• Non-anatomical closed reduction
• Displaced Salter III & IV fractures
– Open reduction to remove soft tissue
interposition
– Internal fixation with screws parallel to physis
or crossed K-wires traversing the physis
– Protect fixation with splint in slight knee
flexion
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
SH IV Proximal Tibia Fx
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Complications
– Loss of reduction
– Compartment syndrome
– Growth disturbance
– Ligamentous instability
Extra-articular Knee Injuries
Proximal Tibial Epiphysis
Growth disturbance
– Incidence is limited by anatomical reduction
– May be corrected with resection of bony bridge
or osteotomy depending on patient age
Tibial Tubercle Avulsion
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Anatomy
– Tibia tubercle physeal development
• Cartilaginous stage: through 9-10 y.o.
• Apophyseal stage: ossification center appears 8-14
y.o.
• Epiphyseal stage: ossification centers of tubercle
and epiphysis merge 10-17 y.o.
• Bony stage: physis is closed btw tuberosity and
metaphysis
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Fracture Epidemiology
– Mechanism
• Jumping sports – eccentric contraction of extensor
mechanism during landing
• 98% males
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Physical Examination
– Anterior proximal tibia swelling and tenderness
– Joint effusion/hemarthrosis
– Palpable bony fragment
– Tented skin
– Patella alta may be present
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Associated Injuries
– Knee ligament injury
– Meniscal injury
– Extensor mechanism disruption
– Tibia plateau fracture
Extra-articular Knee Injuries
Tibial
Tubercle
Avulsion
Radiographs
– AP and LAT xrays
– Slightly internally rotated
lateral view may aid
visualization of tibial tubercle
due to anatomical location
lateral to tibial midline
– Fracture is differentiated from
Osgood-Schlatter by acute
fracture line through physis
(Osgood-Schlatter does not
involve the physis)
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Classification (Watson-Jones, with modifications
of Ogden, Ryu, and Inoue)
– Type I: Fracture through the tubercle apophysis
– Type II: Fracture through the apophysis that
extends between ossification centers of apophysis
and epiphysis
– Type III: Fracture through apophysis extends
across epiphysis
– Type IV: Fracture through apophysis extends
posteriorly at level of tibial phsysis
– Type V: Avulsion of patellar tendon off tubercle
physis (sleeve fracture)
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Type III Avulsion Fx
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Intervention
– Closed reduction and casting
– ORIF
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Closed treatment and casting
– Indications: minimally displaced fractures after
closed reduction
– Reduction with knee in extension
– Cast molding above patella is important to
maintain reduction
– Maintain in cast for 6 weeks
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Open Reduction and Internal Fixation
– Midline incision
– Periosteum is debrided from fracture line
– Reduction by knee extension
– Screw or pin fixation should be supported by
soft tissue repair
– Protect repair with cylinder cast for 6 weeks
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Type II Avulsion Fx
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Type III Avulsion Fx
Extra-articular Knee Injuries
Tibial Tubercle Avulsion
Complications
– Growth disturbance
– Compartment syndrome
– Symptomatic hardware (approx. 50%)
– Stiffness (loss of flexion)
Patella Fracture
Extra-articular Knee Injuries
Patella Fracture
Mechanism:
– Avulsion fractures of patella more likely in
children than adults
– Eccentric contraction
– Direct blow (comminuted fracture)
Extra-articular Knee Injuries
Patella Fracture
Physical Examination
– Painful swollen knee
– Inability to extend knee
– Inability to bear weight
– High riding patella
– Apprehension test may be positive if patient has
avulsion fracture secondary to patellar
dislocation
Extra-articular Knee Injuries
Patella Fracture
Radiographs
– AP & LAT knee xrays
– Sagittal plane fractures may be best seen with
sunrise view
– Sleeve fracture – small fleck of bone in
extensor mechanism may be only sign of
disruption
– Comparison views of normal knee may be
required
Extra-articular Knee Injuries
Patella Fracture
Classification
– Primary osseous fractures
– Avulsion fractures
• Avulsion of pole of patella without significant
avulsion of cartilage
– Sleeve fractures
• Avulsion of pole of patella WITH a large portion of
articular cartilage (cartilage, retinaculum, and
periosteum may be involved)
Extra-articular Knee Injuries
Patella Fracture
Intervention
– Closed treatment with casting
– Open reduction and internal fixation
Extra-articular Knee Injuries
Patella Fracture
Closed treatment
– Extensor mechanism is intact
– No significant displacement (<2-3mm at
articular surface)
Extra-articular Knee Injuries
Patella
Fracture
Open reduction and internal
fixation
– Midline incision
– ORIF with tension band
wire, cerclage wire,
nonabsorbable suture,
screws
– Sutures alone sufficient for
patella sleeve fractures
– Repair of retinaculum is
recommended
– Splint for 4-6 weeks
recommended
Extra-articular Knee Injuries
Summary
ANATOMICAL REDUCTION
– Key to preventing physeal arrest, malalignment,
and LLD
PREVENT LOSS OF REDUCTION
– Loss of reduction is common if not treated with
stable reduction and fixation
TEMPORARY PROTECTION OF
FIXATION
– Postop splint/cast important in treatment
Intra-articular Knee Injuries
Overview
Intra-articular Knee Injuries
– Tibial Eminence Fractures
– Osteochondral Fractures
– Patella Dislocation
– Menicus Injuries
– Ligament Injuries
Acute Hemarthrosis in Children-without
Obvious Fracture
Anterior Cruciate Tear
Meniscal tear
Patellar dislocation +/- osteochondral fracture
Knee Injuries
Acute Hemarthrosis
ACL
Meniscal tear
Fracture
50%
40%
10%
Intra-articular Knee Injuries
Tibial Eminence Fractures
Epidemiology
– Usually 8-14 year old children
– Mechanism:
• Hypertension or direct blow to flexed knee
• Frequently mechanism is fall from bicycle
Intra-articular Knee Injuries
Tibial Eminence Fractures
Myers- McKeever Classification
– Type I- nondisplaced
– Type II- hinged with posterior attachment
– Type III- complete, displaced
Intra-articular Knee Injuries
Tibial Eminence Fractures
Intervention
– 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
Intra-articular Knee Injuries
Tibial Eminence Fractures
8 to 14 yo
often bicycle accident
Myer-McKeever
classification
Tibial Spine Fracture
Treatment
Reduction in extension
Immobilize in extension or slight knee flexion
Operative treatment for failed reduction or
extension block
Tibial Spine Closed Reduction
Follow closely – get full extension
Tibial Spine MalunionLoss of Extension
Injury Film – no reduction
2 years post-injury- lacks extension
Tibial Spine FxArthroscopic OR,Suture Fixation
Intra-articular Knee Injuries
Tibial Eminence Fractures
Outcomes
– 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
Intra-articular Knee Injuries
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
Intra-articular Knee Injuries
Patellar Dislocation
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
Patellar Dislocation
Note Medial Avulsion off Patella and
Laxity in Medial Retinaculum
Intra-articular Knee Injuries
Patellar Dislocation
Predisposing factors to recurrenceligamentous laxity, increased genu valgum,
torsional malalignment
Consider surgical treatment for recurrent
dislocation/subluxation if fail extensive
rehabilitation/exercises
Intra-articular Knee Injuries
Patellar Dislocation
Lateral Patellar Dislocation
Intra-articular Knee Injuries
Meniscal Injuries
Epidemiology
– Increasing incidence
– Longitudinal and bucket handle tears common
– Often associated with ACL tear
Intra-articular Knee Injuries
Meniscal Injuries
Mechanism
– Almost exclusively sporting injuries
– Twisting motion that occurs as knee is
extending
Intra-articular Knee Injuries
Meniscal Injuries
Physical Examination
– Inaccurate for diagnosis of meniscal tear
– Acute swelling and hemarthrosis
– Joint line tenderness
– Motion at joint line with varus/valgus stress
Intra-articular Knee Injuries
Meniscal Injuries
Radiographs
– Conventional xrays do not visualize
– May be associated with discoid meniscus on
MRI
Intra-articular Knee Injuries
Meniscal Injuries
Intervention
– Nonoperative – nondisplaced, small, outer 1/3
– Partial meniscectomy - complex tears with
degenerative changes
– Meniscal repair – simple tears in inner and
middle 1/3 tears
Intra-articular Knee Injuries
Meniscal Injuries
Outcomes
– Poor results with sub-total meniscectomy
– Repair is successful in most patients < 30y.o.
Intra-articular Knee Injuries
Meniscal Injuries
Complications
– Hemorrhage
– Persistent effusion
– Infection
– Stiffness
– Neuropathy
Intra-articular Knee Injuries
Ligament Injuries
Epidemiology
– Increasing incidence
– ACL tear occurs in 10-65% of pediatric
hemarthrosis
– Boys 16-18 y.o. in organized sports
– Girls 13-15 y.o. in unorganized sports
Stanitski CL. JPO 1993;13:506.
Intra-articular Knee Injuries
Ligament Injuries
Mechanism
– Cutting maneuvers while running
– Lateral blow to the knee in abduction, flexion,
and internal rotation while competing in sports
Intra-articular Knee Injuries
Ligament Injuries
Intervention
– Nonoperative
• Frequently successful in isolated collateral ligament tears
• May be attempted for incomplete ACL and PCL tears
– Operative
• Advocated for complete ACL tears to prevent sequelae
of cartilage damage and meniscal injury
• Advocated for displaced complete PCL injury with bony
avulsion (attempted nonop treatment is encouraged for
pure ligamentous injury)
Intra-articular Knee Injuries
Ligament Injuries
Knee Dislocation
– 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
Intra-articular Knee Injuries
Overview
Intra-articular Knee Injuries
– Tibial Eminence Fractures
– Osteochondral Fractures
– Patella Dislocation
– Menicus Injuries
– Ligament Injuries
Pediatric Knee Injuries
Extra-articular injuries
– Distal Femoral Epiphysis
– Proximal Tibia Epiphysis
– Tibia Tubercle
– Patella
Intra-articular injuries
– Tibial Eminence Fractures
– Osteochondral Fractures
– Patella Dislocation
– Menicus Injuries
– Ligament Injuries
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