p10 pediatric knee
TRANSCRIPT
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