orthopaedics and trauma

1. Fractures of the Pelvis
and Acetabulum in
Pediatric Patients
Steven Frick, MD

2. Anatomy - Pelvis
• Iliac bone with iliac apophysis
• Ischium with apophysis
• Pubic bones – physeal connection at
ischiopubic junction
• Sacrum – SI joint 2/3 synchondrosis, 1/3
synovial joint
• Pubic symphysis - synchondrosis

3. The Child’s Pelvis
• Fundamental Differences:
– Bones more malleable
– Cartilage capable of absorbing more energy
– Joints more elastic
– Triradiate Cartilage

4. Elasticity of Joints
• Sacroiliac Joint and Pubic Symphysis more
elastic
• Allows significant displacement
• Allows for single break in the ring
• Thick periosteum – apparent dislocations
may have a periosteal tube that heals like a
fracture

5. AcetabularAnatomy
• 3 Primary Ossification Centers:
– Pubis
– Ischium
– Ilium

6. Acetabular Anatomy
• These 3 distinct physes along all cartilage
borders allow hemispheric growth of both
the acetabulum and pelvis.
• The 3 ossification centers meet and fuse at
the Triradiate cartilage at age 13-16 years

7. Infant Acetabulum
Triradiate Cartilage
Complex
• Separates the Iliac
bone, the Pubic bone
and the Ischial Bone

8. Infant Acetabulum
Histologic Section of
Infant Acetabulum
• Acetabular Cartilage
• Triradiate Cartilage
• Labrum
• Pulvinar
• Capsule
• Ilium
From Ponseti et al, JBJS

9. Development of the Acetabulum
• Interstitial growth within the Triradiate
cartilage complex allows enlargement
• Concavity = response to the femoral head

10. Development of the Acetabulum
• Depth of the acetabulum results from:
– interstitial growth in the acetabular cartilage
– appositional growth of the periphery of this
cartilage
– periosteal new bone formation at the acetabular
margin.

11. Puberty
• 3 Secondary Ossification center appear in
the Hyaline Cartilage:
– os acetabuli (epiphysis of the pubis)
– acetabular epiphysis (epiphysis of the ilium)
– secondary ossification center of the ischium

12. Adolescent Acetabulum
Adolescent’s Innominate
Bone
Secondary Ossification Centers
• OA - Os Acetabuli
• AE - Acetabular Epiphysis
• PB - Pubic Bone
• SCI - Secondary Ossification
Center of the Ischium
SCI

13. Adolescent Acetabulum
• The Os Acetabuli forms the anterior wall of the
acetabulum
• The Acetabular Epiphysis forms a good part of the
superior wall of the acetabulum
• The secondary ossification center of the ischium
develops into the ischial acetabular cartilage

14. Anatomy
• Other Secondary Ossification Centers of
the Pelvis
– iliac crest
– ischial apophysis
– anterior inferior iliac spine
– pubic tubercle
– angle of the pubis
– ischial spine
– lateral wing of the sacrum

15. Secondary Ossification Center
• Iliac Crest : first seen at age 13 to 15 and fuses at
age 15 to 17 years
• Ischium : first seen at age 15 to 17 and fuses at
age 19 to 25 years
• ASIS : first seen about age 14 and fusing at age 16
*(Important to know these secondary ossification centers so
they will not be confused with avulsion fractures)

16. Weakness of Cartilage
• Avulsion fractures occur more often in
children and adolescents through apophysis
• Fractures of the acetabulum into the
triradiate cartilage may occur with less
energy than adult acetabular fractures

17. History and Associated Injuries
• Usually high energy injuries for pelvic ring and
acetabular fractures
• Other associated injuries
– Orthopaedic – long bone or spine fractures
– Urologic – bladder rupture
– Vascular – less frequent than in adults

18. Physical Examination
• A, B, C’s
• Trauma evaluation
• Orthopaedic exam all extremities and spine
• Systematic approach to the Pelvis

19. Examination of the Pelvis
• Areas of contusion, abrasion, laceration,
ecchymosis, or hematoma, especially in the
perineal and pelvic areas, should be recorded.
• Landmarks such as the anterior superior iliac
spine, crest of the ilium, sacroiliac joints, and
symphysis pubis should be palpated.
• Carefully evaluate perineum/genital/rectal areas in
fractures with significant displacement to rule out
open fractures

20. Examination of the Pelvis
• Provocative Tests (ie. Compressing the pelvic ring
with anterior-posterior and lateral compression
stress)
• The range of motion of the extremities, especially
of the hip joint, should be determined
• Neurologic and vascular exam of the lower
extremities

21. Radiographic Evaluation
• Standard AP Pelvis
• Judet views for acetabular involvement
• Inlet/Outlet views for pelvic ring injuries
• Computed tomography
– 2-d and 3-d reconstruction
• Cystography and/or urography if blood at meatus
or on bladder catheterization

22. Pelvic Avulsion Fracture Injuries
• At sites of muscle attachments through
apophyses, caused by forceful contraction
• Iliac wing – tensor fascia lata
• Anterior superior iliac spine – sartorius
• Anterior inferior iliac spine – rectus femoris
• Ischium – hamstrings
• Lesser trochanter - iliopsoas

23. Relative Percentages of Pelvic
Avulsion Fracture Locations

24. ASIS Avulsion Fracture

25. Pelvic Ring Injuries
• Often high energy mechanism
• MVC, pedestrian vs. car, fall from height
• Often other fractures present
• TBI, intraabdominal and urologic injuries
often associated
• Neurologic and vascular injuries may occur
with severe disruptions

26. Classification of Pelvic Injuries
in Children
Torode and Zieg Modification of Watts Classification
• Type I – avulsion fractures
• Type II - Iliac wing fractures
• Type III – stable pelvic ring injuries
• Type IV – any fracture pattern creating a
free bony fragment (unstable pelvic ring
injuries)

27. Tile Classification
(applicable to adolescents /
patients near skeletal maturity)
• Type A – stable
• Type B – rotationally unstable, vertically
stable
• Type C – rotationally and vertically
unstable

28. Treatment Options
• Bedrest
• Spica cast
• Mobilization with restricted weightbearing
• Skeletal traction
• External fixation
• ORIF

29. Treatment Differences
• Pubic symphyseal and SI disruptions may be able
to be treated closed because of potential for
periosteal healing
• Children tolerate bedrest/traction/immobilization
better than adults
• Operative fixation should spare growth plates
when possible
• When not possible consider temporary (4-6
weeks) fixation across physes with smooth pins

30. Treatment
• Most avulsion injuries, Tile A fractures
treated with restricted or no weightbearing
• Most Tile B fractures treated
nonoperatively unless major deformity
• Tile C fractures may need stabilization

31. Treatment Caveats
• Older children and adolescents with pelvic
injuries treated like adults
• Operative treatment in general for pelvic
injuries where posterior ring disruptions are
displaced or unstable
• May be able to stabilize anterior ring only,
and for shorter time period if using external
fixation

32. 13 Year Old, Bilateral Pubic Rami
Fractures with Left SI Disruption
Subtrochanteric Femur Fracture

33. Pediatric Acetabular Fractures
• Not common
• Historically treated nonoperatively
• Classification by injury pattern (shear or
compression), growth plate injury, or as in
adults with Letournel

34. Incidence of Triradiate
Cartilage Injury
Review of the Literature: (0.8% - 15%)
• 2/237 (0.8%) Jurkovskj 1945
• 3/52 (6%) Bryan and Tullos (1 significant) 1979
• 4/84 (5%) Reed 1976
• 13/221 (11.9%) Ljubosic 1967
• ~12% Bucholz et al 1982
• 4/27 (15%) Heeg et al 1988

35. Pubic ramus fractures and
triradiate cartilage injury
OFTEN associated ring injury

36. Triradiate Cartilage
Fractures through this physeal cartilage in
children can ultimately cause:
– growth arrest
– leg-length discrepancy
– faulty development of the acetabulum

37. Age is a significant risk factor in the
development of post-traumatic acetabular
dysplasia.
Children younger than ten years of age at the
time of injury are at greatest risk
Bucholz 1982

38. Triradiate Physeal Closure
• Can occur following nondisplaced or
minimally displaced fractures
• Possible consequences are progressive
acetabular dysplasia with shallow
acetabulum and subluxation, thickening of
medial acetabular wall, hypoplastic
hemipelvis

39. Classification of Injury
• Injuries to the triradiate cartilage constitute
physeal trauma
• Two basic patterns:
– Shearing Type (Salter-Harris Type 1 or 2)
– Crushing or Impaction Type (Type 5)

40. Bucholz et al: JBJS(A) 1982

41. Shearing Pattern with Central
Protrusio of Femoral Head

42. CT Scan Shearing Type

43. Shearing Type
• Blow to the pubic or ischial ramus or the proximal
end of the femur
• Injury at the interface of the 2 superior arms of the
triradiate cartilage and the metaphysis of the ilium
• A triangular medial metaphyseal fragment
(Thurston-Holland sign) may be seen in the S-H
Type II injuries

44. Shearing Type
• Effectively splits the acetabulum into superior
(main weight-bearing) one-third and inferior (non-
weight-bearing) two-thirds
• Germinal zones contained within the physes
unaffected
• Favorable prognosis for continued relatively
normal growth and development of the
acetabulum

45. Crushing or Impaction Type
• Difficult to detect on initial radiographs
• Narrowing of the triradiate space suggests this
injury pattern (rarely seen)
• Premature closure of the triradiate cartilage
appears to be the usual outcome
• The earlier in life the premature closure occurs,
the greater the eventual acetabular deformity

46. Treatment Options
• Non-operative Treatment
• Operative Treatment
– ORIF
– Early Reconstruction
– Late Reconstruction

47. Non-operative Treatment
Majority in the Literature
Treatment:
– Traction
– Spica Cast
– Bedrest
– Protected mobilization

48. • Bucholz et al reported 50% (4/8) rate of
growth disturbance
• Only one with acetabular dysplasia
– this patient injured at a young age
Bucholz et al 1982

49. Non-operative Treatment
Conclusion:
• Mixed Results
• Results often poor, especially in cases with
comminution, incongruity and when
traction does not improve position of
fracture fragments

50. Operative Treatment
• ORIF
• Early Reconstruction (Physeal Bar
excision)
• Late Reconstruction (Pelvic Osteotomy)

51. Acetabular Fractures in Children-
Indications for ORIF
• Joint displacement > 2mm
• Joint incongruity
• Joint instability (fracture dislocations)
• Able to undergo anesthetic

52. Displaced Acetabular Fracute
3D CT – Shows “Free Fragment”

53. Post-Op- smooth Kwire across
Triradiate cartliage
6 Weeks Post-Op

54. 3 Month Follow-up

55. Literature Review: ORIF Pediatric Acetabular Fracture
Author Age at Injury Time of F/U
Comment_____________________
Bucholz et al 6 18mo Asymptomatic; lost 15 degrees of IR
1982 X-ray: Osseous Acetabular overgrowth
Brooks and 10 48mo Asymptomatic; full range of motion
Rosman X-ray: Normal
1988
Heeg et al 9 72mo Skeletally Mature; pain-free, but walks
1988 w/ severe limp; 25 degree fixed flx, 25
degrees fixed IR, 20 degrees fixed
adduct, 3 cm short
X-ray: subluxation of femoral head
Operative Treatment-ORIF
• Three Case Reports
– Bucholz et al: JBJS (A), 1982
– Brooks and Rosman: J of T, 1988
– Heeg et al: JBJS (B), 1988

56. Pre-Op Post-Op
Bucholz et al 1982

57. Bucholz et al 1982
At 18 months Post-Op
Osseous Acetabular Overgrowth

58. Pre-Op Post-Op
Brooks and Rosman 1988

59. Brooks and Rosman 1988
At 48 months Post-Op
?Osseous Bridge?

60. Operative Treatment
ORIF
Conclusion:
– Early Results appear Good/Excellent
– Intermediate results questionable
– One case with Long-term follow-up shows
Poor results
– Need longer followup

61. Older child – displace posterior column
through triradiate “scar” – ORIF with
plate / lag screw on posterior column

62. Heeg et al. CORR July 2000
• Retrospective, 29 patients, age 2-16 years
• 14 year avg followup
• ORIF 14, arthrotomy 2 , 13 nonoperative
• All but one satisfactory function
• Central fracture dislocation relatively poor
because of failure to achieve radiographic
congruence, even with surgery
• Need longer followup

63. Operative Treatment
Early Reconstruction
• Hamlet and Robertson: JBJS(A)1997
• Single Case Report
• 14 year follow-up
• Initial treatment = Non-operative
• Physeal Bar Excision/Bone Wax
Interposition

64. Operative Treatment
Early Reconstruction
• 5 YO s/p MVA sustains a minimally
displaced R acetabular fracture

65. Operative Treatment
Early Reconstruction
• At age 7, tomograms
shows evidence of
physeal bar formation

66. Operative Treatment
Early Reconstruction
• Age 7
• S/p excision of
physeal bar (1982)
• Bone wax
interposition
• WBAT post-op day 5

67. Operative Treatment
Early Reconstruction
• At age 19, there is slight increase in width of
acetabular wall and lateral displacement of
femoral head.
• Suggests premature closure of triradiate cartilage

68. Operative Treatment
Early Reconstruction
• Conclusion:
– Small physeal bars are amenable to excision
– Premature closure of Triradiate still occurs
despite bar excision
– Recommend: Early recognition and treatment
prior to premature closure of entire physis and
permanent osseous deformity

69. • “Theoretically, if the osseous bridge were
removed surgically, growth would resume and the
normal shape of the acetabulum might be
preserved. However, the rapid development of the
osseous bridge and progression to closure of the
triradiate cartilage certainly suggest that resection
of the bridge and implantation of fat… may not
have much success.”
Bucholz et al, 1982

70. Operative Treatment
Late Reconstruction (SALVAGE)
• Two Case Reports
– Blair and Hanson: JBJS(A) 1979
– Scuderi and Bronson: CORR 1987
• Conservative Management Initially
• Premature closure of Triradiate Cartilage
• Symptomatic treatment
• Chiari Osteotomy at maturity

71. Operative Treatment
Late Reconstruction (SALVAGE)
Conclusion:
– Results Not KNOWN
– Salvage procedure
Chiari Osteotomy

72. Conclusion
• Pediatric Acetabular fractures are rare
• Potential complication = Triradiate
Cartilage injury
• Traumatic acetabular dysplasia
– growth arrest
– faulty development of the acetabulum
• shallow acetabulum
• femoral head subluxation/dislocation
– leg-length discrepancy

73. Conclusion
• Risk factors include:
– Age (<10 years)
– S-H Type 5 injury pattern
• Diagnosis:
– High level of suspicion
– CT scan helpful

74. Conclusion
• Treatment:
– Non-operative (Majority)
– Operative
• Acute ORIF – gaining favor, similar treatment
principles as adults
• Reconstruction
– Early
– Late
• Results:
– No Long-term follow-up

75. Conclusion
Recommendation:
• Non/Min displaced fractures = Non-operative
– Patient treated non-operatively should be followed
for at least one – two years
– Those that progress to premature triradiate cartilage
fusion = consider Early Reconstruction
– Those presenting late with subluxation= Salvage
Procedure
• Displaced fractures = ORIF
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