Pediatric Knee Injuries

1. 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

2. 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

3. Overview Extra-articular injuries Intra-articular injuries

4. Overview Extra-articular Knee Injuries Distal Femoral Epiphysis Proximal Tibia Epiphysis Tibia Tubercle Patella

5. Overview Intra-articular Knee Injuries Tibial Eminence Fractures Osteochondral Fractures Patella Dislocation Menicus Injuries Ligament Injuries

6. Distal Femoral Epiphyseal Fractures

7. 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

8. Extra-articular Knee InjuriesDistal 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

9. Extra-articular Knee InjuriesDistal Femoral Epiphysis Physical Examination Pain Inability to bear weight Obvious deformity Swelling and ecchymosis Anterior displacement may be associated with vascular injury

10. Extra-articular Knee InjuriesDistal 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

11. Extra-articular Knee InjuriesDistal 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)

12. Extra-articular Knee InjuriesDistal Femoral Epiphysis Interventions Closed reduction and immobilization Closed reduction and internal fixation ORIF

13. Extra-articular Knee InjuriesDistal 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

14. Extra-articular Knee InjuriesDistal 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 43-70% displace without internal fixation

15. Extra-articular Knee InjuriesDistal 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

16. Extra-articular Knee InjuriesDistal Femoral Epiphysis Open Reduction and Internal Fixation INDICATIONS Fractures that cannot be satisfactorily reduced closed Salter III and IV fractures Open fractures Floating knee

17. Extra-articular Knee InjuriesDistal Femoral Epiphysis

18. Extra-articular Knee InjuriesDistal 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

19. Salter IV Distal Femur Fracture

20. Extra-articular Knee InjuriesDistal 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

21. Extra-articular Knee InjuriesDistal Femoral Epiphysis Complications of Injury Ligamentous laxity Knee stiffness Compartment syndrome Malalignment Shortening Loss of reduction

22. Extra-articular Knee InjuriesDistal Femoral Epiphysis SH II Fx

23. Extra-articular Knee InjuriesDistal Femoral Epiphysis

24. Extra-articular Knee InjuriesDistal Femoral Epiphysis 6 mo postop

25. Extra-articular Knee InjuriesDistal Femoral Epiphysis

26. Extra-articular Knee InjuriesDistal Femoral Epiphysis

27. Extra-articular Knee InjuriesDistal Femoral Epiphysis SH IV FX with distal metaphyseal femur fx

28. Extra-articular Knee InjuriesDistal Femoral Epiphysis

29. Extra-articular Knee InjuriesDistal 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

30. Distal Femur Physeal Bar

31. Valgus deformity, short limb following distal femur SII fx with growth arrest, failed bar excision

32. Extra-articular Knee InjuriesDistal Femoral Epiphysis Severe growth plate injury 9 years after SH II distal femoral physeal injury in 4 y.o. girl

33. Proximal Tibial Epiphyseal Fractures

34. 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

35. Extra-articular Knee InjuriesProximal 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

36. Extra-articular Knee InjuriesDistal 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

37. Extra-articular Knee InjuriesProximal 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

38. Extra-articular Knee InjuriesProximal Tibial Epiphysis Intervention Closed reduction and immobilization Closed reduction and internal fixation ORIF

39. Extra-articular Knee InjuriesProximal 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

40. Extra-articular Knee InjuriesProximal 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

41. Extra-articular Knee InjuriesProximal 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

42. Extra-articular Knee InjuriesProximal Tibial Epiphysis SH IV Proximal Tibia Fx

43. Extra-articular Knee InjuriesProximal Tibial Epiphysis

44. Extra-articular Knee InjuriesProximal Tibial Epiphysis

45. Extra-articular Knee InjuriesProximal Tibial Epiphysis

46. Extra-articular Knee InjuriesProximal Tibial Epiphysis Complications Loss of reduction Compartment syndrome Growth disturbance Ligamentous instability

47. Extra-articular Knee InjuriesProximal Tibial Epiphysis Growth disturbance Incidence is limited by anatomical reduction May be corrected with resection of bony bridge or osteotomy depending on patient age

48. Tibial Tubercle Avulsion

49. 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

50. Extra-articular Knee InjuriesTibial Tubercle Avulsion Fracture Epidemiology Mechanism Jumping sports – eccentric contraction of extensor mechanism during landing 98% males

51. Extra-articular Knee InjuriesTibial Tubercle Avulsion Physical Examination Anterior proximal tibia swelling and tenderness Joint effusion/hemarthrosis Palpable bony fragment Tented skin Patella alta may be present

52. Extra-articular Knee InjuriesTibial Tubercle Avulsion Associated Injuries Knee ligament injury Meniscal injury Extensor mechanism disruption Tibia plateau fracture

53. Extra-articular Knee InjuriesTibial 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)

54. Extra-articular Knee InjuriesTibial 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)

55. Extra-articular Knee InjuriesTibial Tubercle Avulsion Type III Avulsion Fx

56. Extra-articular Knee InjuriesTibial Tubercle Avulsion Intervention Closed reduction and casting ORIF

57. Extra-articular Knee InjuriesTibial 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

58. Extra-articular Knee InjuriesTibial 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

59. Extra-articular Knee InjuriesTibial Tubercle Avulsion Type II Avulsion Fx

60. Extra-articular Knee InjuriesTibial Tubercle Avulsion Type III Avulsion Fx

61. Extra-articular Knee InjuriesTibial Tubercle Avulsion Complications Growth disturbance Compartment syndrome Symptomatic hardware (approx. 50%) Stiffness (loss of flexion)

62. Patella Fracture

63. Extra-articular Knee InjuriesPatella Fracture Mechanism: Avulsion fractures of patella more likely in children than adults Eccentric contraction Direct blow (comminuted fracture)

64. Extra-articular Knee InjuriesPatella 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

65. Extra-articular Knee InjuriesPatella 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

66. Extra-articular Knee InjuriesPatella 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)

67. Extra-articular Knee InjuriesPatella Fracture Intervention Closed treatment with casting Open reduction and internal fixation

68. Extra-articular Knee InjuriesPatella Fracture Closed treatment Extensor mechanism is intact No significant displacement (<2-3mm at articular surface)

69. Extra-articular Knee InjuriesPatella 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

70. 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

71. Intra-articular Knee InjuriesOverview Intra-articular Knee Injuries Tibial Eminence Fractures Osteochondral Fractures Patella Dislocation Menicus Injuries Ligament Injuries

72. Acute Hemarthrosis in Children-without Obvious Fracture Anterior Cruciate Tear Meniscal tear Patellar dislocation +/- osteochondral fracture

73. Knee InjuriesAcute Hemarthrosis ACL 50% Meniscal tear 40% Fracture 10%

74. 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

75. Intra-articular Knee InjuriesTibial Eminence Fractures Myers- McKeever Classification Type I- nondisplaced Type II- hinged with posterior attachment Type III- complete, displaced

76. Intra-articular Knee InjuriesTibial 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

77. Intra-articular Knee InjuriesTibial Eminence Fractures 8 to 14 yo often bicycle accident Myer-McKeever classification

78. Tibial Spine FractureTreatment Reduction in extension Immobilize in extension or slight knee flexion Operative treatment for failed reduction or extension block

79. Tibial Spine Closed Reduction

80. Tibial Spine Malunion-Loss of Extension

81. Tibial Spine Fx- Arthroscopic OR,Suture Fixation

82. Intra-articular Knee InjuriesTibial 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

83. 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

84. 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

85. Patellar DislocationNote Medial Avulsion off Patella and Laxity in Medial Retinaculum

86. Intra-articular Knee InjuriesPatellar Dislocation Predisposing factors to recurrence- ligamentous laxity, increased genu valgum, torsional malalignment Consider surgical treatment for recurrent dislocation/subluxation if fail extensive rehabilitation/exercises

87. Intra-articular Knee InjuriesPatellar Dislocation

88. Intra-articular Knee InjuriesMeniscal Injuries Epidemiology Increasing incidence Longitudinal and bucket handle tears common Often associated with ACL tear

89. Intra-articular Knee InjuriesMeniscal Injuries Mechanism Almost exclusively sporting injuries Twisting motion that occurs as knee is extending

90. Intra-articular Knee InjuriesMeniscal Injuries Physical Examination Inaccurate for diagnosis of meniscal tear Acute swelling and hemarthrosis Joint line tenderness Motion at joint line with varus/valgus stress

91. Intra-articular Knee InjuriesMeniscal Injuries Radiographs Conventional xrays do not visualize May be associated with discoid meniscus on MRI

92. Intra-articular Knee InjuriesMeniscal 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

93. Intra-articular Knee InjuriesMeniscal Injuries Outcomes Poor results with sub-total meniscectomy Repair is successful in most patients < 30y.o.

94. Intra-articular Knee InjuriesMeniscal Injuries Complications Hemorrhage Persistent effusion Infection Stiffness Neuropathy

95. 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

96. Intra-articular Knee InjuriesLigament Injuries Mechanism Cutting maneuvers while running Lateral blow to the knee in abduction, flexion, and internal rotation while competing in sports

97. Intra-articular Knee InjuriesLigament 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)

98. Intra-articular Knee InjuriesLigament 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

99. Intra-articular Knee InjuriesOverview Intra-articular Knee Injuries Tibial Eminence Fractures Osteochondral Fractures Patella Dislocation Menicus Injuries Ligament Injuries

100. 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

101. Thank You