Korean J Radiol.  2010 Feb;11(1):84-94. 10.3348/kjr.2010.11.1.84.

Ultrasound Diagnosis of Either an Occult or Missed Fracture of an Extremity in Pediatric-Aged Children

• Cho KH
• Lee SM
• Lee YH
• Suh KJ

• KMID: 1787018
• DOI: http://doi.org/10.3348/kjr.2010.11.1.84

Abstract

OBJECTIVE
To report and assess the usefulness of ultrasound (US) findings for occult fractures of growing bones.
MATERIALS AND METHODS
For six years, US scans were performed in children younger than 15 years who were referred with trauma-related local pain and swelling of the extremities. As a routine US examination, the soft tissue, bones, and adjacent joints were examined in the area of discomfort, in addition to the asymptomatic contralateral extremity for comparison. Twenty-five occult fractures in 25 children (age range, five months-15 years; average age, 7.7 years) were confirmed by initial and follow-up radiograms, additional imaging studies, and clinical observation longer than three weeks.
RESULTS
The most common site of occult fractures was the elbow (n = 9, 36%), followed by the knee (n = 7, 28%), ischium (n = 4, 16%), distal fibula (n = 3, 12%), proximal femur (n = 1, 4%), and humeral shaft (n = 1, 4%). On the retrograde review of the routine radiographs, 13 out of the 25 cases showed no bone abnormalities except for various soft tissue swelling. For the US findings, cortical discontinuity (direct sign of a fracture) was clearly visualized in 23 cases (92%) and was questionable in two (8%). As auxiliary US findings (indirect signs of a fracture), step-off deformities, tiny avulsed bone fragments, double-line appearance of cortical margins, and diffuse irregularity of the bone surfaces were identified.
CONCLUSION
Performing US for soft tissue and bone surfaces with pain and swelling, with or without trauma history in the extremities, is important for diagnosing occult or missed fractures of immature bones in pediatric-aged children.

Keyword

Bone; Fracture; Children; Extremity; Ultrasound (US)

MeSH Terms

Adolescent
Arm Bones/injuries/radiography/*ultrasonography
Child
Child, Preschool
Female
Fractures, Bone/radiography/therapy/*ultrasonography
Humans
Infant
Leg Bones/injuries/radiography/*ultrasonography
Male

Figure

• 

  Fig. 1 (Case No. 3). 2-year-old boy denied use of his right arm. A-P radiogram of right arm (A) shows no abnormality. Lateral longitudinal US of right elbow (B) depicts fracture at growth plate (*), which is widened compared to left arm (C). Result is separation of unmineralized capitellum (C) from metaphyseal end of distal humerus (m) with no step-off deformity of bone surface. Radiograph obtained one month post-surgery (D) shows periosteal reaction in distal humerus.

• 

  Fig. 2 (Case No. 16). 4-month-old female infant with history of prematurity. Radiograph (A) shows suspicious bone deformity in distal femoral metaphysis without fracture line. No visualization of ossification centers in knee is representing of delayed bone growth. Longitudinal US in anterior aspect of distal femur (B) depicts buckled cortical line (arrow) with impacted fracture at metaphysis. Distal epiphysis (e) is composed of unmineralized cartilage with no calcified ossification center.

• 

  Fig. 3 (Case No. 19). 14-year-old boy with history of direct blow on anterior aspect of right knee. Initial routine A-P and lateral radiographs (A, B) of right knee are unremarkable. Anterior transverse US scan of right knee (C) shows step-off deformity of bone surface with thickened medial retinaculum (dotted rectangle) in medial aspect of right patella (p) compared to left patella (D). Avulsion (sleeve) fracture is well compatible with that (dotted rectangle) of axial view of proton density fat-saturated MR image (E) and axial view of patella (F) which are performed in addition after US.

• 

  Fig. 4 (Case No. 12). 8-year-old girl with history of blunt trauma in left buttock as result of slip-down. Pelvis A-P view (A) shows questionable asymmetric radiolucency (arrow) at junction of pubis and ischium on left side when compared to right side. US of undersurface of right ischium (B) is normal in terms of bone surface continuity (arrows). Bone surface of left ischium (C) shows diffuse irregularity with posterior sonic enhancement (dotted rectangle). MRI shows fracture (arrows) and peri-osseous hemorrhage in left ischium on T1-, and T2-weighted axial images (D, E) and T2-weighted fat-saturated sagittal image (F) along ischium.

• 

  Fig. 5 (Case No. 8). 9-year-old boy with unremarkable A-P radiogram of right elbow (A). Longitudinal US on medial aspect of right elbow (B) reveals thin avulsed bone fragment (arrow) inferior to medial epicondyle (me) is seen, deep into medial collateral ligament (arrowheads) compared to asymptomatic left elbow (C). Follow-up A-P radiograph after two months (D) clearly shows avulsed bone fragment (arrow).

• 

  Fig. 6 (Case No. 10). 9-year-old boy with left elbow pain after slip-down. Initial lateral radiogram of left elbow (A) shows no abnormality. Follow-up posterior long-axis view of olecranon (o) on US (B) shows double-line cortex with tiny break-down of bone surface continuity (dotted rectangle). Olecranon epiphysis (e) is in unmineralized cartilage state. Distal triceps brachii tendon (arrows) inserts onto posterior aspect of olecranon. Follow-up lateral radiograph (C) after two weeks clearly shows fracture (arrow).

• 

  Fig. 7 (Case No. 7). 11-year-old boy with right elbow tenderness after slip-down 10 days ago underwent routine A-P and lateral radiogram of both right (A, B) and left (C, D) elbows. There are too many secondary ossification centers which make interpretation difficult. Lateral radiograph of right elbow (B) shows posterior elbow fat pad sign (arrowheads) and anterior sail sign (arrow). Anterior long-axis view on US of right (E) elbow over capitellum (c) shows thin fragment and cortical disruption at fracture (arrow), deepened radial fossa (f) and angled deformity of anterior bone alignment (dashed line) in distal humerus compared to asymptomatic left elbow (F). MRI T2-weighted sagittal section of right elbow (G) shows effusion (f) and non-displaced impacted fracture (arrow) in distal end of metaphysis.

• 

  Fig. 8 Summarized diagram of US findings of occult fractures: A, normal; B, non-displaced (hairline) fracture; C, minimally displaced fracture with step-off deformity; D, impact fracture with step-off deformity; E, fracture with double-line cortex; F, fracture with diffuse irregularity of bone surface; G, growth plate fracture; and H, avulsion fracture.

Reference

1. Naranja RJ Jr, Gregg JR, Dormans JP, Drummond DS, Davidson RS, Hahn M. Pediatric fracture without radiographic abnormality. Description and significance. Clin Orthop Relat Res. 1997. 342:141–114.

2. Carson S, Woolridge DP, Colletti J, Kilgore K. Pediatric upper extremity injuries. Pediatr Clin North Am. 2006. 53:41–67.

3. Swischuk LE, Hernandez JA. Frequently missed fractures in children (value of comparative views). Emerg Radiol. 2004. 11:22–28.

4. Haddad-Zebouni S, Abi Khalil S, Roukos S, Menassa-Moussa L, Smayra T, Aoun N, et al. Limb fractures: ultrasound imaging features. J Radiol. 2008. 89:557–563.

5. Furnival RA, Woodward GA, Schunk JE. Delayed diagnosis of injury in pediatric trauma. Pediatrics. 1996. 98:56–62.

6. Cho KH, Lee YH, Lee SM, Shahid MU, Suh KJ, Choi JH. Sonography of bone and bone-related diseases of the extremities. J Clin Ultrasound. 2004. 32:511–521.

7. May DA, Disler DG, Jones EA, Pearce DA. Using sonography to diagnose an unossified medial epicondyle avulsion in a child. AJR Am J Roentgenol. 2000. 174:1115–1117.

8. Graif M, Stahl-Kent V, Ben-Ami T, Strauss S, Amit Y, Itzchak Y. Sonographic detection of occult bone fractures. Pediatr Radiol. 1988. 18:383–385.

9. Lazar RD, Waters PM, Jaramillo D. The use of ultrasonography in the diagnosis of occult fracture of the radial neck. A case report. J Bone Joint Surg Am. 1998. 80:1361–1136.

10. Ditchfield A, Sampson MA, Taylor GR. Case reports. Ultrasound diagnosis of sleeve fracture of the patella. Clin Radiol. 2000. 55:721–772.

11. Eliahou R, Simanovsky N, Hiller N, Simanovsky N. Fracture-separation of the distal femoral epiphysis in a premature neonate. J Ultrasound Med. 2006. 25:1603–1605.

12. Williamson D, Watura R, Cobby M. Ultrasound imaging of forearm fractures in children: a viable alternative? J Accid Emerg Med. 2000. 17:22–24.

13. Zuazo I, Bonnefoy O, Tauzin C, Borocco A, Lippa A, Legrand M, et al. Acute elbow trauma in children: role of ultrasonography. Pediatr Radiol. 2008. 38:982–988.

14. Simanovsky N, Lamdan R, Hiller N, Simanovsky N. Sonographic detection of radiologically occult fractures in pediatric ankle and wrist injuries. J Pediatr Orthop. 2009. 29:142–145.

15. Weishaupt D, Schweitzer ME. MR imaging of the foot and ankle: patterns of bone marrow signal abnormalities. Eur Radiol. 2002. 12:416–426.

16. Berger PE, Ofstein RA, Jackson DW, Morrison DS, Silvino N, Amador R. MRI demonstration of radiographically occult fractures: what have we been missing? Radiographics. 1989. 9:407–436.

17. Singer J, Towbin R. Occult fractures in the production of gait disturbance in childhood. Pediatrics. 1979. 64:192–196.

18. Sankar WN, Chen J, Kay RM, Skaggs DL. Incidence of occult fracture in children with acute ankle injuries. J Pediatr Orthop. 2008. 28:500–501.

19. Kan JH, Estrada C, Hasan U, Bracikowski A, Shyr Y, Shakhtour B, et al. Management of occult fractures in the skeletally immature patient: cost analysis of implementing a limited trauma magnetic resonance imaging protocol. Pediatr Emerg Care. 2009. 25:226–230.

20. Grechenig W, Clement HG, Fellinger M, Seggl W. Scope and limitations of ultrasonography in the documentation of fractures--an experimental study. Arch Orthop Trauma Surg. 1998. 117:368–371.

21. Mah ET, LeQuesne GW, Gent RJ, Paterson DC. Ultrasonic features of acute osteomyelitis in children. J Bone Joint Surg Br. 1994. 76:969–974.

22. Wright NB, Abbott GT, Carty HM. Ultrasound in children with osteomyelitis. Clin Radiol. 1995. 50:623–627.