p10 pediatric knee

Fractures and Dislocations about the Knee

in Pediatric Patients

Steven Frick, MD

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

Anatomy- Neurologic and Vascular Structures

• Popliteal artery tethered above and below knee

• Common peroneal nerve vulnerable at fibular neck/head

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

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

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

Anatomy Predisposing to 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

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”

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

Distal Femoral Physeal Fractures

• direct blow mechanism

• Salter I or II common

• check neurologic / vascular status

Treatment Recommendations

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

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

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

Graham & Gross, cont.

• Angular deformity and LLD related to the amount of initial deformity and the quality of reduction

• Recommended rigid internal fixation

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

Lombardo & Harvey, JBJS ‘’77

• 34 distal femoral physeal fx. Followed avg. four years

• >2cm 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

Be Wary of Fixation Only in Thurston-Holland Fragment

Loss of reduction at 2 weeks

Distal Femoral Physeal Fractures

• closed reduction and pinning for displaced fractures

• long leg cast

Distal Femoral Physeal Fractures

• high rate of premature growth arrestrare < 2 yo

80% 2 - 11 yo50% > 11 yo

• angular deformity• leg length discrepancy

Salter IV Distal Femur Fracture – Lateral Growth Arrest

Salter IV Distal Femur Fracture

Distal Femur Physeal Bar

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

Physeal Bars

• male : female - 2 : 1

• distal femur, distal tibia, proximal tibia, distal radius

Patellar Sleeve Fracture

• 8-12 year old• Inferior pole sleeve of cartilage may

displace• May have small ossified portion• <2mm displaced, intact extensor

mechanism- treat non-operatively

Patella Fractures

• much less common than adults

• avulsion mechanism• patellar sleeve fracture• management same as

adults• Restore articular

surface and knee extensor mechanism

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

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%

Tibial Eminence Fractures

• 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

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

Tibial Spine Fracture

• 8 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 Fracture

• 50% still have ACL laxity• loss of extension very debilitating

Tibial Spine Fx- Arthroscopic ORIF

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

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)

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

Tibial Tubercle Fractures- Treatment

• Nondisplaced, intact extensor mechanism- above knee immobilization for 6 weeks in extension

• Displaced, loss of extensor mechanism integrity- operative fixation

Tibial Tubercle Fracture

• 10 - 14 year old • often during

basketball• surgery for

displaced fractures, inability to extend knee

Proximal Tibial Physeal Fractures

• Usually Salter II fractures.• Occasionally Salter I or IV• Posterior displacement of epiphysis or

metaphysis can cause vascular compromise

Proximal Tibia Fracture

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

Proximal Tibia Salter I Fracture

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

Complications

• angular deformity• malunion• physeal bar

• leg length discrepancy

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)

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

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

Genu Valgum following Proximal Tibia Metaphyseal Fracture

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

Patellar DislocationNote Medial Avulsion off Patella and Laxity in Medial Retinaculum

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

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

Return to Pediatrics Index