pediatric knee injuries greg m. osgood, md revised 2011 additional images courtesy of paul...

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 InjuriesDistal 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


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.


Physical Examination– Pain

– Inability to bear weight– Obvious deformity

– Swelling and ecchymosis

– Anterior displacement may be associated with

vascular injury


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


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)


Interventions– Closed reduction and immobilization– Closed reduction and internal fixation

– ORIF


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


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– 43-70% displace without internal fixation

Thomson J. JPO 1995;15:474.Graham JM. CORR 1990;255:51.


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


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 InjuriesDistal Femoral EpiphysisOpen 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


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


Complications of Injury– Ligamentous laxity

– Knee stiffness– Compartment syndrome

– Malalignment– Shortening

– Loss of reduction


SH II Fx


6 mo postop


SH IV FX with distal metaphyseal femur fx


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


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 InjuriesProximal 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


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


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


Radiographs– AP & LAT xrays

– Frequently minimally displaced & easily overlooked

– Stress xrays may help– CT may help assess possible Salter III or IV

– MRI


Intervention– Closed reduction and immobilization– Closed reduction and internal fixation

– ORIF


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


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


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


SH IV Proximal Tibia Fx


Complications– Loss of reduction

– Compartment syndrome– Growth disturbance

– Ligamentous instability


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 InjuriesTibial 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


Fracture Epidemiology– Mechanism

• Jumping sports – eccentric contraction of extensor mechanism during landing

• 98% males


Physical Examination– Anterior proximal tibia swelling and tenderness

– Joint effusion/hemarthrosis– Palpable bony fragment

– Tented skin– Patella alta may be present


Associated Injuries– Knee ligament injury

– Meniscal injury– Extensor mechanism disruption

– Tibia plateau fracture

Extra-articular Knee InjuriesTibial Tubercle AvulsionRadiographs

– 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)


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)


Type III Avulsion Fx


Intervention– Closed reduction and casting

– ORIF


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


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


Type II Avulsion Fx


Type III Avulsion Fx


Complications– Growth disturbance

– Compartment syndrome– Symptomatic hardware (approx. 50%)

– Stiffness (loss of flexion)

Patella Fracture

Extra-articular Knee InjuriesPatella Fracture

Mechanism:– Avulsion fractures of patella more likely in

children than adults– Eccentric contraction

– Direct blow (comminuted 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


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


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)


Intervention– Closed treatment with casting

– Open reduction and internal fixation


Closed treatment– Extensor mechanism is intact

– No significant displacement (<2-3mm at articular surface)


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 InjuriesSummary

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 InjuriesOverview



Acute Hemarthrosis in Children-without Obvious Fracture

Anterior Cruciate Tear

Meniscal tear

Patellar dislocation +/- osteochondral fracture

Knee InjuriesAcute Hemarthrosis

ACL 50%

Meniscal tear 40%

Fracture 10%

Intra-articular Knee InjuriesTibial Eminence Fractures

Epidemiology– Usually 8-14 year old children

– Mechanism: • Hypertension or direct blow to flexed knee

• Frequently mechanism is fall from bicycle


Myers- McKeever Classification– Type I- nondisplaced

– Type II- hinged with posterior attachment– Type III- complete, displaced


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 InjuriesTibial Eminence Fractures8 to 14 yo

often bicycle accident

Myer-McKeever classification

Tibial Spine FractureTreatment

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 Malunion-Loss of Extension

Injury Film – no reduction 2 years post-injury- lacks extension

Tibial Spine Fx- Arthroscopic OR,Suture Fixation


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 InjuriesOsteochondral 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 InjuriesPatellar 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 DislocationNote Medial Avulsion off Patella and

Laxity in Medial Retinaculum


Predisposing factors to recurrence- ligamentous laxity, increased genu valgum,

torsional malalignment

Consider surgical treatment for recurrent dislocation/subluxation if fail extensive

rehabilitation/exercises


Lateral Patellar Dislocation

Intra-articular Knee InjuriesMeniscal Injuries

Epidemiology– Increasing incidence

– Longitudinal and bucket handle tears common– Often associated with ACL tear


Mechanism– Almost exclusively sporting injuries

– Twisting motion that occurs as knee is extending


Physical Examination– Inaccurate for diagnosis of meniscal tear

– Acute swelling and hemarthrosis– Joint line tenderness

– Motion at joint line with varus/valgus stress


Radiographs– Conventional xrays do not visualize

– May be associated with discoid meniscus on MRI


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


Outcomes– Poor results with sub-total meniscectomy

– Repair is successful in most patients < 30y.o.


Complications– Hemorrhage

– Persistent effusion– Infection– Stiffness

– Neuropathy

Intra-articular Knee InjuriesLigament 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.


Mechanism– Cutting maneuvers while running

– Lateral blow to the knee in abduction, flexion, and internal rotation while competing in sports


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)


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 InjuriesOverview



Pediatric Knee Injuries

Extra-articular injuries– Distal Femoral Epiphysis– Proximal Tibia Epiphysis

– Tibia Tubercle – Patella

Intra-articular injuries– Tibial Eminence Fractures– Osteochondral Fractures


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pediatric knee injuries greg m. osgood, md revised 2011 additional images courtesy of paul...

Documents

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capsule slide

pediatric knee injuries

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recurvatum fractures

proximal tibial physis