Fractures of the Pelvis and
Acetabulum in Pediatric Patients
Joshua Klatt, MD
Revised - October, 2011
Created March 2004 by Steven Frick, MD
The Child’s Pelvis
• Fundamental differences:
–
–
–
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Bones are more malleable
Cartilage is capable of absorbing more energy
SI joint and symphysis are more elastic
Triradiate Cartilage
• Injury causing growth arrest may lead to significant
deformity
Schlickwei W, Keck T. Pelvic and acetabular fractures in
childhood.
Elasticity of Joints
• Sacroiliac joint and pubic symphysis are
more elastic
• Allows significant displacement before fx
• Allows for single break in the ring
• Thick periosteum
– Apparent dislocations may have a periosteal
tube that heals like a fracture
Schlickwei W, Keck T. Pelvic and acetabular fractures in
childhood.
Pelvic Anatomy
• 3 primary ossification
centers:
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–
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Ilium – appears at 9 wks
Ischium – appears at 16 wks
Pubis – appears at ~20 wks
Endochonral ossification, just like
long bones
Delaere O, Dhem A. Prenatal development of the human pelvis
and acetabulum. Acta Orthop Belg. 1999;65(3):255-60.
Acetabular Anatomy
• The 3 distinct physes of
each bone making up the
triradiate cartilage 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
Ponseti, I. Growth and development of the acetabulum in the
normal child. Anatomical, histological, and
roentgenographic studies. J Bone Joint Surg Am.
Triradiate Cartilage Complex
• Separates the ilium,
the pubis and the
ischium
Ponseti, I. J Bone Joint Surg Am. 1978.
Infant Acetabulum
Histologic section of
infant acetabulum
•
•
•
•
•
•
Acetabular cartilage
Triradiate cartilage
Labrum
Pulvinar
Capsule
Ilium
Ponseti, I. J Bone Joint Surg Am. 1978.
Development of the Acetabulum
• Interstitial growth within
the horizontal flange of
the triradiate cartilage
contributes to the normal
growth of the distal third
of the ilium.
• Enlargement of the
acetabulum during growth
is likely the result of
interstitial growth within
the triradiate cartilage.
Ponseti, I. J Bone Joint Surg Am. 1978.
Development of the Acetabulum
• Development of concavity is a response to
pressure from the femoral head
– In DDH with a dislocation the acetabulum will not
develop appropriately
• 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.
Puberty
• 3 secondary ossification centers appear in
the hyaline cartilage of the acetabulum
– Os acetabuli
• Epiphysis of the pubis
• Forms most of anterior wall
– Acetabular epiphysis
• Epiphysis of the ilium
• Forms most of superior acetabulum
– Secondary ossification center of the ischium
• Forms much of posterior wall
Secondary Ossification Centers
SCI
• OA - Os Acetabuli
• AE - Acetabular
Epiphysis
• PB - Pubic Bone
• SCI – Secondary
ossification center of
ischium
• Ossification centers appear
at age 8 to 9 yrs and fuse
around 17 – 18 yrs
Ponseti, I. J Bone Joint Surg Am. 1978.
Anatomy
• Other secondary ossification centers of the
pelvis
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Iliac crest
Ischial apophysis
Anterior inferior iliac spine
Pubic tubercle
Angle of the pubis
Ischial spine
Lateral wing of the sacrum
Secondary Ossification Center
• Iliac Crest : first seen at age 13 to 15 and fuses at
age 15 to 17 years
– Used in Risser staging
• 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
Weakness of Cartilage
• Avulsion fractures occur more often in
children and adolescents through an
apophysis
• Fractures of the acetabulum into the
triradiate cartilage may occur with less
energy than adult acetabular fractures
History and Associated Injuries
• Pelvic ring and acetabular fractures usually
involve high energy injuries
• Associated injuries
– Orthopaedic – long bone or spine fractures
– Urologic – bladder rupture
– Vascular – less frequent than in adults, rarely life
threatening
Physical Examination
• A, B, C’s
• Trauma evaluation
• Orthopaedic exam of extremities and spine
• Systematic approach to the pelvis
Examination of the Pelvis
• Areas of contusion, abrasion, laceration,
ecchymosis, or hematoma, especially in the
perineal and pelvic areas, should be noted
– Rule out open fractures in perineum/genital/rectal areas
• Palpate landmarks
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Anterior superior iliac spine
Crest of the ilium
Sacroiliac joints
Symphysis pubis
Examination of the Pelvis
• Neurologic and vascular exam of the lower
extremities
• Provocative Tests
– Compress 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
Radiographic Evaluation
• There is no standard algorithm for which films to
obtain in children
• AP pelvis
• Judet views for acetabular involvement
• Inlet/Outlet views for pelvic ring injuries
• Computed tomography
– 2D and possibly 3D reconstruction
• Cystography/urography if blood at meatus or on
bladder catheterization
Pelvic Avulsion Fractures
• Caused by forceful contraction at sites of
muscle attachments through apophyses
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Iliac wing – tensor fascia lata
Anterior superior iliac spine – sartorius
Anterior inferior iliac spine – rectus femoris
Ischium – hamstrings
Lesser trochanter - iliopsoas
Relative Percentages of Pelvic
Avulsion Fracture Locations
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•
•
•
•
Ischial tuberosity – 54%
AIIS – 22%
ASIS – 19%
Pubic Symphysis – 3%
Iliac Crest – 1%
http://crashingpatient.com
Rossi F, Dragoni S. Acute Avulsion Fractures of
the Pelvis in Adolescent Competitive Athletes.
Skeletal Radiol. 2001;30(3):127-31.
ASIS Avulsion Fracture
Ischial Avulsion Fracture
11 yr male sprinting
CT of ischial avulsion fracture
AIIS Avulsion Fracture
13 yr female kicking a soccer ball
Pelvic Ring Injuries
• Often high energy mechanism
– MVA
– Auto-pedestrian
– Fall from height
• Often other fractures present
– Traumatic brain injury (TBI)
– Intra-abdominal injuries
– Urologic injuries
• Neurologic and vascular
injuries may occur with severe
disruptions
Torode I, Zieg D. Pelvic fractures in children.
J Pediatr Orthop 1985;5:76-84.
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)
Torode I, Zieg D. Pelvic fractures in children.
J Pediatr Orthop 1985;5:76-84.
Tile Classification
• Applicable in patients
near skeletal maturity
– More often adult type
patterns
• Type A – Stable
• Type B – Rotationally
unstable, vertically
stable
• Type C – Rotationally
and vertically unstable
Tile M. Acute Pelvic Fractures: I. Causation
and Classification? J Am Acad Orthop Surg.
1996;4(3):143-151.
Treatment Options
•
•
•
•
•
•
Bedrest
Spica cast
Restricted weight bearing
Skeletal traction
External fixation
ORIF
Treatment Differences
• Children tolerate bedrest/traction/immobilization
better than adults
• Pubic symphyseal and SI disruptions may be able
to be treated closed because of potential for
periosteal healing
• Operative fixation should spare growth plates
when possible
– When not possible consider temporary (4-6 weeks)
fixation across physes with smooth pins or early
hardware removal
Holden C, et al. Pediatric pelvic fractures.
J Am Acad Orthop Surg. 2007;15:172-7.
Pelvic Ring Injuries
*Often crush mechanism and can have severe soft tissue injuries as well.
Treatment
• Most avulsion injuries and Tile A fractures
treated with restricted or no weight bearing
• Most Tile B fractures treated nonoperatively
unless major deformity
• Tile C fractures may need stabilization
Holden C, et al. Pediatric pelvic fractures.
J Am Acad Orthop Surg. 2007;15:172-7.
Treatment Caveats
• Treat older children and adolescents with
pelvic injuries like adults
• In general, pelvic injuries where posterior
ring disruptions are displaced or unstable
need operative treatment
• Only anterior ring may need stabilization
– And for shorter time period, if using external
fixation
Holden C, et al. Pediatric pelvic fractures.
J Am Acad Orthop Surg. 2007;15:172-7.
Plate Symphysis for Diastasis
13 year old, bilateral pubic rami
fractures with left SI disruption
subtrochanteric femur fracture
Pediatric Acetabular Fractures
• Constitute only 1% to 15% of pelvic
fractures in children
– Much more common after the triradiate
cartilage closes (12 yrs in girls, 14 yrs in boys)
• Mechanism of injury similar to that in
adults
– Force transmitted through femoral head
– Position of leg relative to pelvis and location of
impact determine fracture pattern
Pediatric Acetabular Fractures
• Often associated with hip dislocation
• The distribution of types is different than adults
– More often transverse than both column
• Historically treated nonoperatively
– Achieving congruent reduction with closed,
conservative treatment is difficult and often impossible
– Many think that the role of surgical treatment in
children is expanding
Heeg M, de Ridder VA. Acetabular fractures in
children and adolescents. Clin Orthop Relat Res
Pediatric Acetabular Fractures
Classification
• Growth plate injury
– Use Salter-Harris classification
– Bucholz suggested that there are common
injury patterns
• Letournel system most frequently used
– Same as used for adults
• Watts classification also sometimes used
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Pediatric Acetabular Fractures
Classification
• Letournel system
– Type A – Single wall or column
– Type B – Fractures involving 2 columns
– Type C – Fractures involve both columns and
separate dome fragment from axial skeleton
Judet, et al. Fractures of the acetabulum: classification
and surgical approaches for open reduction.
J Bone Joint Surg Am 1964;46:1615-46.
Pediatric Acetabular Fractures
Classification
• Watts classification
– Type A – Small fragments that most often occur with
hip dislocation
– Type B – Stable linear fractures without displacement
in association with pelvic fractures
– Type C – Linear fractures with hip joint instability
– Type D – Fractures secondary to central fracturedislocation of the hip
Watts HG. Fractures of the pelvis in children.
Orthop Clin North Am 1976;7:615-624.
Pediatric Acetabular Fractures
Classification
• Injuries to the triradiate cartilage constitute
physeal trauma
• Bucholz Classification
– Two basic patterns
– Shearing Type (Salter-Harris Type I or II)
– Crushing or Impaction Type (Type IV)
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
•Pubic ramus fractures and
triradiate cartilage injury
•OFTEN associated ring injury
•Watts Type B injury
•Bucholz Shearing Type
•Salter-Harris II
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 SalterHarris Type II injuries
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Shearing Type
• Effectively splits the acetabulum into superior
(main weight-bearing) one-third and inferior (nonweight-bearing) two-thirds
• Germinal zones contained within the physes often
unaffected
• Favorable prognosis for continued relatively
normal growth and development of the
acetabulum
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Shearing Pattern with Central
Protrusio of Femoral Head
•Watts Type D injury
•Bucholz Shearing Type
CT Scan
Shearing Type
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
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Triradiate Cartilage
• Fractures through this physeal cartilage in
children can ultimately cause:
– Growth arrest
– Leg-length discrepancy
– Faulty development of the acetabulum
Heeg, et al. Injuries of the acetabular triradiate cartilage
and sacroiliac joint. J Bone Joint Surg Br 70:34-37,1988.
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, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Incidence of Triradiate
Cartilage Injury
• Of pediatric patients with pelvic trauma,
between 1% and 15% of patients sustain an
acetabular fracture
• In pediatric patients with acetabular
fractures, resulting premature closure of the
triradiate cartilage has an overall incidence
of less than 5% (range, 0–11%)
Liporace, et al. Development and injury of the triradiate
cartilage with its effects on acetabular development:
review of the literature. J Trauma 2003;54(6):1245-9.
Triradiate Physeal Closure
• Can occur following nondisplaced or
minimally displaced fractures
• Possible consequences are
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–
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Progressive acetabular dysplasia
Thickening of medial acetabular wall
Shallow acetabulum and subluxation
Hypoplastic hemipelvis
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Triradiate Physeal Closure
• Bucholz reported 56% (5/9) rate of growth
disturbance (in injuries to triradiate)
– All four of those with Salter-Harris type IV
– Only one with acetabular dysplasia
• Patient injured at a young age (2 yrs)
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Treatment Options
• Unique nature of the developing hip joint
necessitates an individualization of treatment for
each pediatric acetabular fracture
• Agreed that functional outcome determined by
– Age at the time of injury
– Articular displacement
– Congruency of the hip joint
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Treatment Options
• Non-operative treatment
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–
–
–
Traction
Spica Cast
Bedrest
Protected mobilization
• Operative treatment
– ORIF
– Early reconstruction
– Late reconstruction
Non-operative Treatment
• Mixed Results
– Few articles give specific guidelines for
nonoperative versus operative treatment.
• Results often poor, especially in cases with
– Comminution
– Incongruity
– When traction does not improve position of
fracture fragments
Liporace, et al. Development and injury of the triradiate
cartilage with its effects on acetabular development:
review of the literature. J Trauma 2003;54(6):1245-9.
Operative Treatment
• ORIF
– If hardware must cross triradiate cartilage,
consider smooth K-wires
• Early reconstruction (physeal bar excision)
• Late reconstruction (pelvic osteotomy)
Acetabular Fractures in Children
Indications for ORIF
• Joint displacement > 2 mm
• Joint incongruity
• Joint instability (fracture dislocations)
• Fractures with posterior instability
• Persisting medial subluxation
• Central fracture-dislocations
• Intra-articular fragments
• Open fractures
Liporace, et al. Development and injury of the triradiate
cartilage with its effects on acetabular development:
review of the literature. J Trauma 2003;54(6):1245-9.
Displaced Acetabular Fracture
3D CT – Shows “Free Fragment”
Post-op - smooth K-wire across
triradiate cartilage
6 weeks post-op
3 month follow-up
Operative Treatment
• Three Case Examples
– Bucholz. JBJS-Am, 1982
– Brooks and Rosman, J Trauma, 1988
– Heeg, JBJS-Br, 1988
Pre-op
Post-op
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Osseous acetabular overgrowth
18 months post-op
Bucholz, et al. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 1982;64(4):600-9.
Pre-op
Post-op
Brooks E, Rosman M: Central fracture-dislocation
of the hip in a child. J Trauma 28:1590-1592, 1988.
Osseous bridge?
48 months Post-Op
Brooks E, Rosman M: Central fracture-dislocation
of the hip in a child. J Trauma 28:1590-1592, 1988.
Heeg M, de Ridder VA. Acetabular fractures in children
and adolescents. Clin Orthop Relat Res 376:80–6, 2000.
Largest series of pediatric
acetabular fractures
•
•
•
•
•
•
Heeg & Ridder, Netherlands, 2000
Retrospective, 29 patients, age 2-16 years
14 year avg follow-up
14 ORIF, 2 arthrotomy, 13 nonoperative
6 (21%) fair or poor results
Central fracture dislocation relatively poor
because of failure to achieve radiographic
congruence, even with surgery
• Need longer follow-up
Heeg M, de Ridder VA. Acetabular fractures in children
and adolescents. Clin Orthop Relat Res 376:80–6, 2000.
Operative Treatment
Conclusion:
– Early results appear – Good/excellent
– Intermediate results questionable
– One case with long-term follow-up shows poor
results
– Current evidence is poor quality
• Need longer follow-up
• Increased number of reports
Older child – displaced posterior column
through triradiate “scar”
ORIF with plate / lag screw on posterior column
Operative Treatment
Early Reconstruction
•
•
•
•
•
Peterson and Robertson, Mayo Clinic, 1997
Single case report
14 year follow-up
Initial treatment was non-operative
Physeal bar excision/bone wax interposition
Peterson, et al. Premature partial closure of the triradiate cartilage
treated with excision of a physical osseous bar. J Bone Joint Surg
Am. 1997;79(5):767-70.
Operative Treatment
Early Reconstruction
• 5 yr s/p MVA sustains a minimally
displaced R acetabular fracture
Peterson. J Bone Joint Surg Am. 1997.
Operative Treatment
Early Reconstruction
• At age 7, tomograms
shows evidence of
physeal bar formation
Peterson. J Bone Joint Surg Am. 1997.
Operative Treatment
Early Reconstruction
• Age 7
• Excision of physeal
bar (1982)
• Bone wax
interposition
• WBAT post-op day 5
Peterson. J Bone Joint Surg Am. 1997.
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
Peterson. J Bone Joint Surg Am. 1997.
Operative Treatment
Early Reconstruction
• Conclusion:
– Small physeal bars are amenable to excision
– Premature closure of triradiate can still occur
despite bar excision
– Recommendation: Early recognition and
treatment prior to premature closure of entire
physis and permanent osseous deformity
– Based on extremely limited data/experience
Peterson. J Bone Joint Surg Am. 1997.
• “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
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 2 to 3 years prior to
maturity
Operative Treatment
Late Reconstruction (Salvage)
Conclusion:
– Long-term results unknown
– Salvage procedure
Chiari Osteotomy
Conclusion
• Pediatric acetabular fractures are rare
• Potential complication of triradiate
cartilage injury
• Traumatic acetabular dysplasia
– Growth arrest
– Faulty development of the acetabulum
• Shallow acetabulum
• Femoral head subluxation/dislocation
– Leg-length discrepancy
Conclusion
• Risk factors for bar/growth disturbance
include:
– Age (<10 years)
– Salter-Harris type 5 injury pattern
• Diagnosis:
– High level of suspicion
– CT scan helpful
Conclusion
• Treatment
– Non-operative (Majority)
– Operative
• Acute ORIF
– Gaining favor
– Similar treatment principles as adults (>2 mm
displacement)
• Reconstruction
– Early
– Late
• Results
– No long-term follow-up in literature
Conclusion
• Non/min displaced fractures = Non-operative
– Patient treated non-operatively should be followed
for at least one to two years
– Those that progress to premature triradiate cartilage
fusion = consider early reconstruction
– Those presenting late with subluxation = salvage
procedure
• Displaced fractures
– ORIF using adult principles
– If hardware across triradiate required, use smooth
wires
Bibliography
• Blair W, Hanson C. Traumatic closure of the triradiate cartilage: report of a case.
J Bone Joint Surg Am 1979;61(1):144-5.
• Brooks E, Rosman M. Central fracture-dislocation of the hip in a child. J Trauma
28:1590-1592, 1988.
• Bucholz R, Ezaki M, Ogden J. Injury to the acetabular triradiate physeal
cartilage. J Bone Joint Surg Am 64(4):600-9, 1982.
• Delaere O, Dhem A. Prenatal development of the human pelvis and acetabulum.
Acta Orthop Belg. 1999;65(3):255-60.
• Habacker TA, Heinrich SD, Dehne R. Fracture of the superior pelvic quadrant in
a child. J Pediatr Orthop 15:69-72, 1995.
• Hall BB, Klassen RA. Acetabular fractures in children: A long-term follow-up
study. Orthop Trans 6:353. 1982.
• Heeg M, Visser JD, Oostvogel HJM. Injuries of the acetabular triradiate cartilage
and sacroiliac joint. J Bone Joint Surg Br 70:34-37,1988.
• Heeg M, Klasen HJ, Visser JD. Acetabular fractures in children and adolescents.
J Bone Joint Surg-Br 71:418-421, 1989.
Bibliography
• Heeg M, de Ridder VA. Acetabular fractures in children and adolescents. Clin
Orthop Relat Res 376:80–6, 2000.
• Holden CP, Holman J, Herman MJ. Pediatric pelvic fractures. J Am Acad Orthop
Surg. 2007;15:172-7.
• Judet, R, Judet J, Letournel E. Fractures of the acetabulum: classification and
surgical approaches for open reduction. J Bone Joint Surg Am 1964;46:1615-46.
• Liporace F, Ong B, Mohaideen A, Ong A, Koval K. Development and injury of
the triradiate cartilage with its effects on acetabular development: review of the
literature. J Trauma 2003;54(6):1245-9.
• Peterson HA, Robertson RC. Premature partial closure of the triradiate cartilage
treated with excision of a physical osseous bar. Case report with a fourteen-year
follow-up. J Bone Joint Surg Am. 1997;79(5):767-70.
• Ponseti, I. Growth and development of the acetabulum in the normal child.
Anatomical, histological, and roentgenographic studies. J Bone Joint Surg Am.
1978;60(5):575-85.
Bibliography
• Rossi F, Dragoni S. Acute Avulsion Fractures of the Pelvis in Adolescent
Competitive Athletes. Skeletal Radiol. 2001;30(3):127-31.
• Schlickwei W, Keck T. Pelvic and acetabular fractures in childhood. Injury.
2005; 36(suppl 1):A57-A63.
• Scuderi G, Bronson MJ. Triradiate cartilage injury. Report of two cases and
review of the literature. Clin Orthop Relat Res 1987;217:179-89.
• Tile M. Acute Pelvic Fractures: I. Causation and Classification? J Am Acad
Orthop Surg. 1996;4(3):143-151.
• Torode I, Zieg D. Pelvic fractures in children. J Pediatr Orthop 1985;5:76-84.
• Watts HG. Fractures of the pelvis in children. Orthop Clin North Am 1976;7:615624.
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