70 Lebanese Medical Journal 2011 • Volume 59 (2)

AARRTTIICCLLEE OORRIIGGIINNAALL//OORRIIGGIINNAALL AARRTTIICCLLEEULTRASOUND AS AN ADJUNCT TO RADIOGRAPHYIN MINOR MUSCULOSKELETAL PEDIATRIC TRAUMAhttp://www.lebanesemedicaljournal.org/articles/59-2/original3.pdfSamer ABI KHALIL1, Soha HADDAD-ZEBOUNI1, Sami ROUKOZ2, Tarek SMAYRA1, Kamal HACHEM1

Lina MENASSA-MOUSSA1, Noël J. AOUN1, Michel A. GHOSSAIN1

INTRODUCTION

There were major changes in ultrasound equipment thispast decade with a steady and major improvement ofimage quality, and notably of spatial resolution. Thistechnical progress, along with a better knowledge ofmusculoskeletal ultrasound allowed extending its use tomusculoskeletal trauma [1-5]. In these settings, ultra-

sound can play an important role in pediatrics [6-9].Several studies have already shown that ultrasound

imaging can be better than radiography in some circum-stances such as scaphoid fractures in adults and ankle orrib fractures in children [1-3, 9-10]. This study comparesradiography and ultrasound in 50 consecutive pediatricpatients referred for minor limbs trauma.

MATERIALS AND METHODS

A prospective study was undertaken from November2006 to February 2007 concerning 50 consecutive chil-dren, aged between 6 months and 14 years, who had an

Abi Khalil S, Haddad-Zebouni S, Roukoz S, Smayra T,Hachem K, Menassa-Moussa L, Aoun NJ, Ghossain MA.Ultrasound as an adjunct to radiography in minor muscu-loskeletal pediatric trauma. J Med Liban 2011 ; 59 (2) : 70-74.

Abi Khalil S, Haddad-Zebouni S, Roukoz S, Smayra T, Hachem K, Menassa-Moussa L, Aoun NJ, Ghossain MA.L’échographie en complément à la radiographie conventionnelledans le traumatisme musculo-squelettique mineur en pédiatrie. J Med Liban 2011 ; 59 (2) : 70-74.

Departments of Radiology1 and Orthopedics2, CHU Hôtel-Dieude France, Beirut, Lebanon.

Corresponding author: Samer Abi Khalil, MD. RadiologyDepartment. CHU Hôtel-Dieu de France. Alfred NaccacheBoulevard. PO Box 16/6830 Achrafieh. Beirut. Lebanon.

Phone: +961 1 615300 / 3 464545 Fax: +961 1 615295e-mail: aksamer@hotmail.com

ABSTRACT • PURPOSE : To assess the value of ultra-sound as an adjunct to radiography in minor muscu-loskeletal pediatric trauma.

METHODS : Fifty children with 53 suspected frac-tures were referred for upper and/or lower limbs X-rays, followed by ultrasound. On radiography, wenoted presence of fracture, of soft tissue thickening, or absence of any lesion. On ultrasound, we noted pres-ence of fracture, of soft tissue lesion, or absence oflesions.

RESULTS : A fracture was seen on both examinationsin 25 patients with 28 fractures. In 4 patients where onlysoft tissue thickening was seen on radiography, ultra-sound showed fracture in 1 patient, hematoma in 1 pa-tient and was normal in 2 patients. In another patientwith a doubtful diagnosis of fracture on radiography,ultrasound was normal. In 20 patients with normal X-rays, ultrasound showed fracture in 6 patients,hematoma in 7 patients and was normal in 7 patients.

CONCLUSION : Ultrasound was helpful as an ad-junct to radiography, it yielded additional bone (7/50 patients) and soft tissue (8/50 patients) diagnos-tic information in 30% of patients. However, ultra-sound remains operator-dependent and can be usedonly in particular circumstances, especially in chil-dren with normal X-rays and a high index of clinicalsuspicion for an occult or subradiological fracture.

RÉSUMÉ • OBJECTIFS : Evaluer l’intérêt de l’écho-graphie en complément à la radiographie dans lestraumas musculo-squelettiques mineurs de l’enfant.

MÉTHODES : Cinquante enfants avec suspicion de 53 fractures du membre supérieur et/ou inférieur ontété adressés pour une radiographie suivie d’une écho-graphie. Sur la radiographie, on a noté la présenced’une fracture, d’un épaississement tégumentaire, oul’absence de lésion. En échographie, on a noté la pré-sence d’une fracture, d’un épaississement tégumen-taire, ou l’absence de lésion.

RÉSULTATS : Une fracture a été visualisée aux deuxexamens chez 25 patients ayant 28 fractures. Chez 4 patients où un épaississement tégumentaire a été vi-sualisé sur la radiographie, l’échographie a montré unefracture chez 1 patient, un hématome chez 1 patient, etétait normale chez 2 patients. Chez un patient avec uneradiographie douteuse, l’échographie était normale.Dans 20 cas de radiographie normale, l’échographie amontré une fracture chez 6 patients, un hématome chez7 patients, et était normale chez 7 patients.

CONCLUSION : L’échographie a été utile en tant quecomplément à la radiographie et a objectivé des élé-ments diagnostiques supplémentaires osseux (7/50 pa-tients) et des tissus mous (8/50 patients) chez 30% despatients. Toutefois, l’échographie reste un examenopérateur-dépendant et peut être utilisée seulementdans des circonstances particulières, notamment chezles enfants ayant une radiographie normale et unehaute suspicion de fracture.

S. ABI KHALIL et al. – Ultrasound in minor musculoskeletal pediatric trauma Lebanese Medical Journal 2011 • Volume 59 (2) 71

X-ray and an ultrasound for a minor limb trauma. Aminor limb trauma was defined as a limb trauma havingall the following characteristics:

• Involving one or two sites.• Not associated to an open wound.• No fracture detectable on X-ray or fracture detectable

on X-ray but not displaced and involving only onecortical line.

According to our study protocol, a senior pediatric resi-dent or a qualified specialist first examined all patients inthe Emergency Department. Then if a fracture was sus-pected, an X-ray was performed in the Radiology Depart-ment. If the trauma met the criteria of minor as definedabove it was followed systematically by an ultrasoundperformed by a senior radiology resident trained in mus-culoskeletal imaging. He studied the X-rays and per-formed the ultrasound. The combined results of ultra-sound and radiography were presented to the physician in charge of the patient to apply treatment. A specializedmusculoskeletal radiologist reviewed all the X-rays andultrasound examinations within 14 hours.

Ultrasound was performed using Acuson Antares(Siemens Medical Solutions, Mountain View, CA) ma-chine with a linear high resolution probe (13 MHz). Thestudy technique consisted of exploring the painful areaand/or the site of the confirmed or suspected fracture,as well as the cortical line, growth plate cartilage, liga-ments, tendinous structures and the fat planes. A compar-ison with the normal contralateral side was always done.

On X-ray, a fracture was defined as the presence of acortical disruption (classical fracture) or deformity (torusfracture). A soft tissue lesion on X-ray was defined as thepresence of soft tissue thickening.

A fracture on ultrasound was defined as the presence of a cortical disruption or cortical deformity. A hematoma

on ultrasound was defined as the presence of an anechoicor hypoechoic non vascularized collection on colorDoppler; the hematoma, when present, was classified assubperiosteal, juxta-physeal, periarticular or muscular. Aligament lesion on ultrasound was defined as the presenceof one or more of the following findings: 1) thickening ofa ligament, 2) intra-ligament hematoma, and/or 3) disrup-tion of the ligament.

Comparative results between X-rays and ultrasoundwere based on clinical information obtained the day ofinjury, on clinical follow-up, and on follow-up by X-rays:

a. A fracture was considered present when:• seen on X-rays and ultrasound;• in case of discordance between X-ray and ultrasound

for detection of a fracture, the follow-up X-ray waschecked for the presence or absence of bone healing.Fracture was considered present if bone healing wasdetected and absent if no bone healing was detected.

b.A“significant musculoskeletal lesion” was consideredpresent if a fracture was present and/or if a hema-toma or a ligament lesion was seen on ultrasound. Incase of soft tissue thickening on radiography, we con-sidered it true positive if a fracture, a hematoma or aligament lesion was found on ultrasound and falsepositive if ultrasound was strictly normal.

RESULTS

On radiography, 20 patients had a normal radiograph, 25 patients had 28 fractures (associated to soft tissue thick-ening in 4 cases), one patient had a doubtful diagnosis fora fracture and 4 patients had soft tissue thickening only. All28 fractures seen on X-rays were also seen on ultrasound(Fig. 1). In these 28 fractures, ultrasound showed also asubperiosteal hematoma in 27. In one patient a fracture

FIGURE 1

Torus fractureof the distal metaphysisof the radius.

a. Radiography showingthe fracture (arrow).

b. Ultrasound showingthe fracture (arrowhead)associated to subperiostealhematoma (arrow).

72 Lebanese Medical Journal 2011 • Volume 59 (2) S. ABI KHALIL et al. – Ultrasound in minor musculoskeletal pediatric trauma

a. X-ray of the ankle showing soft tissue thickening (arrow).

b. Ultrasound shows a periarticular hematoma of the ankle (arrow).

FIGURE 2. Periarticular hematoma of the ankle.

FIGURE 3. Avulsion fracture at the metaphysis of the proximal humerus.

a. Normal X-ray of the humerus.

b. Ultrasound showed the avulsion fracture (arrow) and the hematoma (arrowhead).

The fractured fragment was separated from the main bone on all views.

S. ABI KHALIL et al. – Ultrasound in minor musculoskeletal pediatric trauma Lebanese Medical Journal 2011 • Volume 59 (2) 73

was suspected radiographically but it was eliminated byultrasound. In 4 patients where soft tissue thickening wasseen on radiography, ultrasound showed a fracture associ-ated to a hematoma located near the growth plate cartilagein one patient, an isolated periarticular hematoma in an-other patient (Fig. 2), and was normal in the remaining 2 patients. In the 20 patients with normal radiography,ultrasound showed a fracture with an associated subperi-osteal hematoma in 6 patients (Fig. 3), an isolated hema-toma in 7 patients (2 subperiosteal, 1 near the growth platecartilage and 4 periarticular), and was normal in 7 patients.Overall, ultrasound showed 35 fractures associated to sub-periosteal hematoma in 33 patients and a juxta-physealhematoma in one patient, as well as 8 isolated hematomas,and 10 normal exams. No ligament lesion, muscular hema-toma or periosteal elevation was found in this series.

Discordance between the radiologist specialized inmusculoskeletal imaging and the radiology senior residentwas present in only one case, a fracture that the radiologyresident missed on radiography but detected on ultra-sound. This case was classified in our results as a positiveX-ray finding of fracture.

In 7 of 8 cases of discordance between X-ray and ultra-sound concerning the presence of a fracture, follow-up X-ray showed callus formation confirming the diagnosisof fracture made by ultrasound. In the last case whereultrasound was normal and a doubtful diagnosis consid-ered on X-ray, the patient was considered as having nofracture and no follow-up X-ray was requested by thephysician because the clinical follow-up was satisfactory.

The results are summarized in table I. Overall, ultra-sound yielded additional bone and soft tissue diagnosticinformation in 30% of traumatized patients.

DISCUSSION

The first applications of ultrasound (US) in musculoskele-tal diseases in children were limited to non ossified struc-tures such as developmental dysplasia of the hip joints and

articular effusions [11]. Afterwards, there were studiescomparing US to X-ray in bone fractures using X-rays asgold standard; these studies showed comparable resultswith some benefit of X-rays in few situations such ascomminuted fracture [6-8, 12]. Other studies followedcomparing ultrasound and X-rays but using a differentgold standard such as MRI, CT scan, radiographic follow-up, or combination of several of these examinations e.g.combination of follow-up X-ray, CT scan, MRI and scin-tigraphy. These studies involved mainly the scaphoidbone and to a lesser extent other areas such as the ankleand demonstrated the superiority of ultrasound in all caseswith sensitivity and specificity values that reached 100%in some series [1-3, 9].

X-ray, as it is shown above, can no more be consideredthe gold standard for diagnosis of occult bone fracture. It isstill considered as a useful tool, easy to access, easy to per-form and easy to read. It can give a rapid overview of thesituation in severe trauma with complex fractures but isless effective than ultrasound performed by an experiencedsonographer for diagnosis of occult fractures as in thisseries i.e. fractures without displacement and only one cor-tical line interrupted or deformed. Performing CT scan orMRI for all patients or patients with discordance betweenresults of ultrasound and X-ray as a routine procedure inour practice is not justified considering cost, irradiation,difficulty to immobilize the child, and previous data thathave shown the reliability of ultrasound in the hands ofexperienced sonographers. A follow-up X-ray looking forbone healing was the reference in our study but the treat-ment was based on findings available on the day of thetrauma. Treatment decisions were based on two principles:

• A fracture was present if seen on either X-ray or ultra-sound. In our series, all fractures seen on X-ray werealso seen by ultrasound. Six fractures with normal X-rays where seen only on ultrasound and follow-upX-rays performed in all these patients confirmed thepresence of bone healing. One patient with a doubt-ful diagnosis of fracture on X-ray had a strictly nor-

TABLE I DETAILED COMPARATIVE RESULTS OF RADIOGRAPHY AND ULTRASOUNDIN 50 PATIENTS WITH 53 SUSPECTED FRACTURES

ULTRASOUND FINDINGS

X-RAYS FINDINGS Fracture Hematoma NormalSubperiosteal Juxta-physeal Periarticular

Fracture [n = 24] 24 23Fracture & soft tissue thickening [n = 4] 4 4

1 1Soft tissue thickening [n = 4) 1

2Suspicious fracture [n = 1) 1

6 62

No anomaly [n = 20] 14

7

74 Lebanese Medical Journal 2011 • Volume 59 (2) S. ABI KHALIL et al. – Ultrasound in minor musculoskeletal pediatric trauma

mal ultrasound, was treated as having no fracture andthe physician in charge did not ask for a follow-up X-ray because the clinical follow-up was uneventful.

• For soft tissue lesions, ultrasound findings were con-sidered more conspicuous and reliable than X-rayfindings, a fact well established.

Ultrasound changed clinical management in severalpatients. In case of negative X-ray and positive ultrasoundfindings for fracture, the patients were treated as having afracture and managed by fixation. In the absence of frac-ture, weight-bearing is allowed in trauma of the lowerlimb, and the upper limb is not put at rest.

The superiority of ultrasound to X-rays in detectingoccult limb fractures can be explained by the accessibilityof the cortical bone surface to high frequency transdu-cers in the pediatric patient. These good results can beachieved even in the hands of an in-training radiologistoutside working hours, provided that trainees have theappropriate training in osteo-articular ultrasound and the dedicated equipment. If these two conditions are notavailable ultrasound can be postponed, to be performed byexperienced radiographers during working hours. How-ever, ultrasound is not useful in open fracture, comminut-ed fracture, polytrauma and skeletal survey.

CONCLUSION

Ultrasound can be superior to radiography in diagnosis ofoccult fractures or hematomas not detected by radiogra-phy. It is also capable of ruling out a fracture in patientswith a doubtful radiographic diagnosis, or a hematoma inpatients with soft tissue thickening. It needs however anexperienced operator and a dedicated equipment, two con-ditions not always available in emergency. This limits itsactual use to an adjuvant examination in patients with ahigh index of clinical suspicion for a fracture and a normalor equivocal radiographic diagnosis.

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