Introduction
After the first description of fracture sonography of the wrist by Saphoznikov [1], this method had no importance in daily practice for a long time. Due to the rapid
development of ultrasound equipment and based on recent structured research results,
fracture sonography has become increasingly important in the last 15 years, resulting
in an increasing number of publications and meta-analyses investigating the safety
and efficiency of the method [2]
[3]
[4]
[5]. The literature describes some preferred indications both in the growing skeleton
and the adult skeleton. Conclusions can then be drawn about the types of injury that
may become part of the spectrum of indications in the future.
In a systematic literature review, the current state of research on fracture ultrasonography
was investigated and based on this, recommendations for the use of the technique were
made in a group of experts. This paper summarizes the recommendations of the expert
group.
Methodology
The 9 participating professional societies (supplementary file “participating professional
associations”) each sent a delegate to the expert group, which developed concrete
recommendations based on the results of the literature search.
Initially in 3/2021, a systematic literature search was conducted in PubMed, Google
Scholar, and the Cochrane Database of Systematic Reviews from 2000 to March 2021.
The search terms are listed in a supplementary file. In addition, relevant publications
were extracted from the literature lists of reviews if they were not already covered
by the search grids. The search covered randomized controlled clinical trials, observational
clinical trials, meta-analyses, and systematic reviews. Guidelines, professional conferences,
case reports, and expert opinions were excluded.
The search was based on PICO criteria (Population, Intervention, Comparison and Outcome)
with the selected keywords being approved by the expert group.
Irrelevant papers were excluded from the publications identified in this manner by
assessing the abstracts. The remaining publications were subjected to a more detailed
analysis based on the full texts. Evidence grading was performed according to the
SIGN grading system 1999–2012 (SIGN 50: a guideline developer's handbook; revised
edition 2019). The SIGN tables were then presented to the expert group. Based on this,
specific recommendations for the use of fracture sonography were developed. All recommendations
were discussed in detail and finally unanimously approved.
Results
Of the 520 identified literature sources, 182 sources (146 clinical studies and 36
meta-analyses and systematic reviews) could be evaluated after screening and content
assessment. The list of anatomic regions is shown in [Table 1].
Table 1 Anatomical regions.
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Anatomical regions
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1. skull fracture
|
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2. clavicle fracture
|
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3. AC joint dislocation
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4. SC joint dislocation
|
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5. proximal humerus fracture
|
|
6. elbow fracture
|
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7. distal forearm fracture
|
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8. scaphoid fracture
|
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9. triquetrum fracture
|
|
10. subcapital 5th metacarpal fracture
|
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11. palmar plate avulsion
|
|
12. rib fracture
|
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13. sternal fractures
|
|
14. femoral bead fractures
|
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15. lower leg fractures
|
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16. toddler’s fracture
|
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17. metatarsal fractures
|
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18. stress fractures
|
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19. fracture dislocation
|
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20. callus presentation
|
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21. pseudarthrosis
|
Skull fracture [2]
[3]
Fractures of the bony skull can also be inadequately visualized on radiographic overviews.
In the absence of neurological symptoms, functional symptom-oriented conservative
therapy is used. As the course of the sutures is known, ultrasound imaging of skull
fractures is possible. By 18 months of age, intracranial injury can also be visualized
([Fig. 1]), but this is reserved for specialists.
Fig. 1 Skull fracture; arrow: cortical step-off.
Therefore, if there are no clinical symptoms that indicate a cross-sectional examination
(MRI or CT), a skull fracture should be diagnosed sonographically at an age of up
to 18 months. If there is suspicion of child abuse, radiological diagnosis is indicated
for forensic reasons.
If child abuse is suspected, X-rays should be taken.
Clavicle fracture [4]
Clavicle fractures in childhood are treated conservatively. Surgical indication is
limited to open fractures and concomitant vascular nerve damage, which are very rare.
If the clinical examination is not sufficient, the clavicle fracture should be diagnosed
sonographically ([Fig. 2]). In the case of complications (vascular/nerve injury), X-ray is mandatory.
Fig. 2 Clavicle fracture arrow: fracture gap.
AC joint dislocation [5]
If there is suspicion of AC joint dislocation, the initial diagnosis can be made sonographically,
since dislocated AC joint dislocations can be easily visualized ([Fig. 3]) with a sensitivity of 100% and a specificity of 84%. This recommendation is valid
from the age of 15 years. For younger patients, no valid data are available. In the
case of doubt or suspicion of additional fractures, an X-ray should be performed.
Fig. 3 Left X-ray, right ultrasound image; yellow marking: clavicle; green: acromion.
SC joint dislocation
Dislocation in the sternoclavicular joint cannot be adequately depicted in conventional
radiology, so that a sectional image examination is necessary here. In an emergency,
CT is usually preferred due to availability and time constraints, but this is associated
with relevant radiation exposure. Ultrasound can substantiate the indication for cross-sectional
imaging by showing a differential finding of the SC joint in the meantime ([Fig. 4]). This recommendation was approved as an expert opinion. Meaningful studies are
not yet available.
Fig. 4 SC dislocation right; green: normal SC joint; yellow: sternum; opposite side: no SC
joint vivid.
Proximal humerus fracture [6]
[7]
A major problem regarding the diagnosis of proximal humerus fracture is that it is
difficult to obtain radiographs in two perpendicular planes. Because of significant
pain, an axial image cannot be obtained, and in the Y-image there is superimposition
by the scapula. On the basis of the images, the correct imaging technique of two perpendicular
planes cannot be checked in many cases, so that uncertainties remain. The proximal
humerus can be reliably visualized sonographically on 4 planes, thus facilitating
the determination of the axial deviation. If there is evidence of a fracture, a radiograph
must be taken to exclude a pathologic fracture, as it cannot be reliably visualized
sonographically. If the sonographic findings are inconspicuous, it is initially possible
to wait. If symptoms persist for more than 5 days, an X-ray check is performed. Fracture
sonography can be used up to the age of 12.
Diagnosis follows the shoulder-SAFE algorithm ([Fig. 5]).
Fig. 5 Shoulder SAFE.
Fractures of the elbow [8]
[9]
In the diagnosis of fractures near the elbow in children up to 12 years of age, sonography
is used as the primary imaging method to detect joint effusion, known from radiography
as the fat-pad sign. If the findings are inconspicuous, conservative pain-oriented
therapy can be used initially. If effusion is detected, X-ray diagnosis on 2 planes
is obligatory. Sonography is used to exclude a fracture. The actual differentiated
fracture presentation is performed radiologically.
Elbows-SAFE is used as the algorithm ([Fig. 6]).
Fig. 6 Elbow SAFE.
Distal forearm fracture [10]
[11]
In distal forearm fractures, sonography is used as a standard diagnostic method until
12 years of age. If the fracture is uncomplicated, X-ray imaging is not required and
is only used in cases of uncertainty or if surgical treatment is planned. Imaging
is performed in 6 longitudinal sections, three each for the radius and ulna. Diagnosis
follows the Wrist-SAFE algorithm ([Fig. 7]).
Fig. 7 Wrist SAFE.
Scaphoid fracture [12]
[13]
Because of the potential complications, the use of fracture sonography in scaphoid
fracture requires adequate expertise. If a scaphoid fracture is clinically suspected
and radiographs are unremarkable, sonography is used for further screening. If the
results are positive for fracture, CT is performed, which offers advantages in visualizing
cortical fractures. If the results are negative, MRI is performed, which is superior
in trabecular injuries.
Triquetral flake fracture [14]
If there is pain over the triquetrum after dorsal extension trauma and radiographic
findings are unremarkable, a triquetral flake fracture can be ruled out before performing
cross-sectional imaging. Thus, unnecessary cross-sectional imaging indications can
be avoided.
Subcapital metacarpal-5 fractures [15]
[16]
In subcapital MHK 5 fractures, the surgical indication depends on the dislocation
of the metacarpal head. As an alternative to strictly lateral radiography, which is
often compromised by superimposition of the other metacarpals, sonographic determination
of axial dislocation can be performed in a volar plane, or in a side-to-side comparison
in the case of uncertainty.
Bony avulsion of the palmar plate [17]
[18]
Avulsions of the palmar plate may escape radiography but can be effectively visualized
sonographically ([Fig. 8]). Therefore, if the symptoms fit and the radiograph is unremarkable, further sonographic
imaging should be performed.
Fig. 8 Bony avulsion palmar plate; arrow: fragment.
Rib fractures [19]
[20]
Detection of rib fractures is more sensitive with ultrasound than radiography (97%
versus 77%). Therefore, after clinical delineation of the region of interest (ROI),
sonographic diagnosis should be given preference ([Fig. 9]). If radiographic imaging has already been performed and the findings are unclear,
sonography can be used on a supplementary basis.
Fig. 9 rib fracture; green: axial buckling, red: hematoma.
Sternal fractures [19]
If a sternal fracture is suspected, fracture ultrasonography is appropriate as a screening
method ([Fig. 10]). If a fracture is confirmed, further imaging should be performed. In the context
of shock room care of trauma patients, sonography should not delay the procedure.
Fig. 10 Left CT image of a sternal fracture, right ultrasound findings; red: axial buckling.
Distal femoral and proximal tibial bead fractures
There are currently no studies on the sonographic evaluation of distal knee joint
compression fractures in growing children. However, since bulge fractures can be very
well visualized sonographically ([Fig. 11]) and have high potential for correction at this site, it is expected that this injury
entity will become a domain of fracture sonography in the future.
Fig. 11 left X-ray of a tibial medial bulge fracture, right ultrasound image; red: bulge fracture.
Toddler’s fracture [21]
Toddler's fracture occurs when children are learning to walk and leads to the patient's
refusal to bear weight. It often causes problems in the delimitation of the ROI (region
of interest), so that in this case, with clear symptoms, an extended X-ray diagnosis
is often performed as a search radiograph, resulting in the ionizing exposure of the
toddler being disproportionate to the diagnostic findings. In this case, sonography
can primarily exclude a bone lesion requiring intervention. If a fracture is visualized
([Fig. 12]), a specific X-ray diagnosis can follow. In the absence of evidence, immobilization
and re-examination is performed after 5–7 days. In this way, unnecessary radiographs
can be avoided.
Fig. 12 Left X-ray, right ultrasound findings of a distal tibia fracture; red: fracture.
Midfoot fractures [22]
[23]
With a sensitivity of 80–97%, sonography should be used as a first-line diagnostic
tool in patients 14 years of age and older when a midfoot fracture is suspected. Dislocations
in the course can also be visualized well. Here, the 1st and 5th rays are visualized
from 3 directions each (dorsal, lateral, plantar), and the 2nd–4th rays from 2 directions
(dorsal and plantar). 45° oblique planes can be added if there is uncertainty.
Stress fracture [24]
Early radiographic diagnosis of stress or fatigue fractures reveals pathology in only
15–20% of cases. Sonography can be used to visualize early signs (cortical disruption,
bulge, small extra fragment, thickening, reverberation artifacts, [Fig. 13]) in these cases, thus substantiating the indication for MRI.
Fig. 13 Fatigue fracture midfoot; arrow: incipient callus.
Callus detection [25]
[26]
Callus formation can be detected much earlier sonographically than radiologically
(in 97% of cases with sonography after 3 weeks, and in 42% with radiology) and is
thus well suited for monitoring the healing process. In the case of suspicion of delayed
bone healing or infection, an X-ray should be performed.
Pseudarthrosis [27]
[28]
If sufficient expertise and logistics allow, contrast-enhanced ultrasound (CEUS) can
be used in pseudarthrosis to diagnose and monitor the progress of an underlying infection.
The method is able to reliably distinguish infected from aseptic pseudarthroses.
