Summary Pelvis Fractures in the pediatric population are uncommon injuries that are usually associated with high-energy trauma and are often associated with CNS and abdominal visceral injury. Diagnosis is made with plain radiographs of the pelvis. CT studies may be required in the setting of occult fractures. Treatment may be nonoperative or operative depending on the location of fracture, presence of pelvic ring instability, and degree of fracture displacement. Epidemiology Incidence uncommon, only 1-2% of all pediatric fractures acetabular fractures only 1-15% of pediatric pelvic fractures Demographics avulsion injuries almost exclusively in adolescent patients Etiology Pathophysiology mechanism of injury pelvic ring injuries login to view 3 more bullets apophyseal avulsions login to view 1 more bullet pathophysiology apophyseal avulsion login to view 1 more bullet pathoanatomy apophyseal avulsion login to view 12 more bullets pelvic ring login to view 11 more bullets acetabular fractures login to view 5 more bullets Associated conditions CNS and abdominal visceral injury high rate (> 50%) in traumatic pelvic injuries login to view 1 more bullet femoral head fractures/dislocations associated with acetabular fractures GU injury increased rate with Torode Type IV fractures life-threatening hemorrhage Anatomy Osteology pelvis undergoes endochondral ossification (like long bones) at 3 primary ossification centers ilium login to view 1 more bullet ischium login to view 1 more bullet pubis login to view 1 more bullet all meet and fuse at 12 in girls and 14 in boys acetabular growth enlargement is a result of interstitial growth within the triradiate cartilage concavity is a response to pressure from the femoral head depth of acetabulum results from login to view 3 more bullets 3 secondary ossification centers of the acetabulum appear at 8-9 and fuse at 17-18 login to view 6 more bullets other secondary ossification centers (of the pelvis) login to view 14 more bullets Classification Tile Classification Type A Stable injuries (rotationally & vertically) Type B Rotationally unstable Vertically stable Type C Unstable rotationally & vertically Torode/Zieg Classification (pediatric pelvic ring) Type I Avulsion injuries Type II Fractures of the iliac wing Type III Fractures of the ring with no segmental instability Type IV Fracture of the ring with segmental instability Bucholz Classification (pediatric acetabulum) Shearing Salter Harris I or II Blow to pubis/ischial ramus/proximal femur leads to injury at interface of 2 superior arms of triradiate cartilage and metaphyses of ilium. A triangular medial metaphyseal fragment (Thurston-Holland fragment) is often seen in SH II injuries. Crushing/Impaction Salter Harris V Difficult to see on initial radiographs May detect narrowing of triradiate space. Leads to premature triradiate cartilage closure. The earlier the closure, the greater the eventual deformity. Presentation History pelvic ring fractures often occur secondary to motor vehicle accidents or when a pedestrian is struck by a motor vehicle pelvic avulsion injuries often occur during sporting activities such as sprinting, jumping or kicking Symptoms pain inability to bear weight hemodynamic instability Physical exam primary exam as in all trauma patients, initial evaluation should include ABC's followed by primary and secondary surveys inspection important to thoroughly complete a rectal/genitourinary evaluation in polytrauma patient to rule out open injury log roll to inspect for soft-tissue contusions and ecchymosis palpation ASIS, iliac crests, SI joints, and pubic symphysis provocative tests posteriorly directed pressure on the iliac crests produces pain at the fracture site compressing pelvic ring at iliac crests causes pain excessive mobility indicative of a serious pelvic injury Imaging Radiographs recommended views AP pelvis Judet views login to view 1 more bullet inlet/outlet views login to view 1 more bullet sensitivity plain radiographs will miss ~50% of all pediatric pelvic fractures CT may be necessary as 50% of all pelvic fractures may be missed on a plain AP pelvis indications negative plain films with increased suspicion when tenderness is present over the SI joints preoperative planning concomitant spine injury findings login to view 1 more bullet MRI indications occasionally required to detect apophyseal avulsion injuries Treatment Nonoperative protected weight bearing followed by therapy indications login to view 8 more bullets technique login to view 6 more bullets bedrest indications login to view 1 more bullet Operative ORIF indications login to view 13 more bullets External fixation indications login to view 2 more bullets Pelvic arteriography indications login to view 2 more bullets Techniques ORIF approach ilioinguinal approach stoppa approach instrumentation physeal sparing when possible when not possible, smooth pins across physis (especially triradiate) x 4-6 weeks with early removal anterior pubic symphysis plating percutaneous SI screw fixation complications specific to treatment early triradiate closure outcomes older children and adolescents with unstable ring fractures may have an improved outcome with internal fixation Complications Death rare most often occur in association with head or visceral injury Pelvic fracture-associated hemorrhage rare see above under death Physeal cartilage injury progressive acetabular dysplasia with thickening of the medial acetabular wall giving rise to shallow acetabulum (lateral hip subluxation) hypoplastic hemipelvis premature closure of triradiate cartilage/growth arrest (<5%) risk factors < 10 old at time of injury login to view 1 more bullet Bucholz crushing type (SH V) treatment reconstruction with physeal bar excision premature triradiate closure can still occur in spite of bar excision late reconstruction with pelvic osteotomy Leg length discrepancy risk factors unstable fracture when vertical displacement of the hemipelvis is >2 cm Malunion/nonunion incidence rare treatment malunion well tolerated due to increased remodeling potential of young children Neurovascular injury Heterotopic ossification Osteonecrosis of the femoral head risk factors acetabular fractures and hip dislocation Degenerative joint disease of the hip risk factors patients with displaced acetabular fractures Prognosis Complications are rare Need for operative intervention increases after the closure of triradiate cartilage