Pediatric Knee Injuries Greg M. Osgood, MD Revised 2011
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 Thank You If you would like to volunteer as an author for the Resident Slide Project or recommend updates to any of the following slides, please send an e-mail to [email protected] E-mail OTA about Questions/Comments Return to Pediatrics Index
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