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Three Part Question

[Can ultrasound be used in th ED] to [diagnose paediatric wrist fractures][reliably and accurately]?

Clinical Scenario

A 4-year-old boy attends the emergency department (ED) complaining of a painful wrist following a fall. You suspect a torus fracture. However, his mum is pregnant and he bursts into tears when you tell him she cannot go into the x ray room with him. You wonder whether ultrasound can be used to diagnose a fracture of the paediatric wrist accurately?

Search Strategy

OVID Medline 1950–June Week 2 2009.
exp radius fracture$/OR exp wrist/OR exp forearm/OR wrist fracture$.mp. OR radius fracture$.mp. OR radial fracture$.mp. OR (torus adj5 fracture$).mp. OR (buckle adj5 fracture$).mp. OR exp ulna fracture$/OR forearm.mp. OR exp fracture$, closed/ AND exp child$/OR child$.mp. OR paediatric$.mp. OR exp pediatrics/OR pediatric$.mp. OR exp child, preschool/OR exp infant OR exp adolescent/OR infant$.mp. Or adolescent$.mp. OR toddler$.mp. AND ultrasonography.mp. OR sonography.mp. OR exp ultrasonics/OR ultrasound.mp. OR exp ultrasonography/ AND exp radiography/OR roentgenogram.mp. OR plain film.mp. OR plain x-ray.mp. OR radiograph$.mp. OR exp x-ray/OR x-ray$.mp. OR xray$.mp. Limit humans and English

Cochrane database—"ultrasound" "wrist" "fracture"

Google search—"ultrasound" "wrist" "fracture"

Search Outcome

Medline—42 papers found, three were relevant

Cochrane—no relevant articles

Google scholar—one extra article found

Four relevant papers have been critically appraised.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Chen et al, 2007, USA	68 Patients aged 2–21 years with suspected forearm fractures were prospectively enrolled June–November 2004 Bedside USS was performed by an ED doctor whose training consisted of a sponsored course followed by one months’ hands-on training in the ED x Ray was performed after and USS result c/w x ray (reported by attending radiologists). Excluded—open fracture, neurovascular compromise, suspicion of associated elbow fracture The decision to MUA was made by the attending ED physician and the orthopaedic team. Reduction was guided by USS then a post-immobilsation x ray was obtained	1b Prospective cohort diagnostic study with gold standard x ray as reference	Accuracy of bedside USS in the diagnosis of children with suspected forearm fractures	48/68 (71%) of patients had 65 fractures	A convenience sample was used, patients only being enrolled when an investigator was present—likely office hours. This may have biased the selection of patients, and also the ability to get an orthopaedic surgeon to do the MUA. Could they offer the same service out of hours/overnight? The study group was aged 2–21 years. At age 21 years, patients will have very different fractures compared with 2 year olds—Colles’ type versus buckle. They are not really comparable groups so this may mean data cannot be extrapolated to all ages in this group The ED physician carrying out the USS had quite intense training? reproducible for all ED staff MUA in the ED is not usually carried out in the ED in the UK so these results will not affect our practice
			Success rate of USS-guided fracture reduction (ie, how many required re-MUA)	29 Radial, 2 ulna, 17 radial/ulna USS identified 63/65 fractures, sensitivity 97% (89–100% 95% CI), specificity 100% (83–100% 95% CI) (The two missed fractures were ulna styloid fractures in patients already identified by USS as having radial fractures—likely clinically insignificant) USS-guided MUA success rate 92% (75–99% 95% CI)
Hubner et al, 2000, Germany	163 Patients with 224 suspected fractures of upper and lower limbs underwent USS by three paediatric surgeons, all of whom had carried out over 1500 scans and had formal training on limb scanning before starting recruitment to the study. Bones were scanned in four planes All patients had USS and then plain x ray Exclusions—open fracture grades 2 or 3, any bone that was obviously deformed or unstable	1b Validating prospective cohort with gold standard x ray as reference standard applied to all patients	Number of correctly diagnosed fractures compared with gold standard x ray	Radial fractures Sensitivity 98.3% Specificity 69.2% Ulna fractures Sensitivity 91.3% Specificity 87.0% All fractures Sensitivity 91.5% Specificity 80%	The surgeons had vast experience in USS Bones were viewed in four planes (c/w two view) Some of the study authors who carried out the USS also gave the final diagnosis of fracture from x ray. Ideally the x rays should have been reported by blinded radiologists. This could have allowed the introduction of bias (though any bias would have been likely to improve results rather than allowing a high number (19) of false positives Side effects were not documented, specifically pain at fracture site Multiple bones were imaged including skull (in the UK skull x rays are rarely done) Little information was given on recruitment method? consecutive patients No demographic data given
Patel et al, 2009, USA	33 Children aged 2–17 years presenting to a PED between March 2006 and January 2007 with suspected fracture radius, ulna, tibia or fibula Small numbers though sample size calculations were done and achieved All patients had an x ray after USS Exclusions—open fracture, neurovascular compromise, haemodynamic compromise, suspected joint involvement	1b Validating prospective cohort with gold standard x ray as reference standard applied to all patients	Agreement between USS and x ray on: fracture identification, need for reduction and adequacy of reduction	USS ID of fracture All fractures: sensitivity 97% (85–100%) Specificity 93% (74–99%) Radius/ulna only: sensitivity 100% (87–100%) Specificity 91% (69–98%) USS ID of need for reduction: All fractures: sensitivity 100% (70–100%) Specificity 85% (61 = 96%) Radius/ulna only: sensitivity 100% (70–100%) Specificity 82% (55–95%) (95% CI in parenthesis) Kappa score for agreement on fracture identification 0.91 (SD 0.05). Need for reduction—kappa 0.85 (SD 0.08) USS also diagnosed four radius/ulna buckle fractures not initially identified on x ray	Small numbers though sample size calculations were done and achieved Demographics not well described Recommendations from Wheeless’ textbook of orthopaedics as gold standard for need for reduction—is this validated? Ideally two radiologists should review all x rays to agree on identification of fracture, and two orthopaedic residents should agree on need for reduction, rather than one in each case as used in this study Side effects, specifically pain at the site during USS, not formally evaluated (though USS was not observed to increase pain) MUA is not pertinent to UK ED practice
Williamson et al, 1999, UK	26 Children aged 2–14 years with high clinical suspicion of non-articular, undisplaced forearm fracture in the year starting July 1997 were recruited. USS was performed by a consultant radiologist and reported immediately, plain x ray was formally reported at a later stage Patients with deformity were excluded	1b—Although pilot study with small numbers	Agreement between formal report of x ray and ultrasound	16 Fractures detected in the 26 patients—there was perfect concordance between USS and x ray Sensitivity and specificity 100% No reports of discomfort were reported (all patients were formally asked during USS)	Very small numbers Consultant radiologist performing and reporting USS—the practical benefit of USS as a diagnostic modality in forearm fractures is that it can be done at the bedside. This would be negated if each child had to wait for a consultant radiologist to be available to perform the scan No information on method of recruitment? consecutive enrolment Radiologist not blinded from the assessing doctors’ index of suspicion for fracture

Comment(s)

There are several factors underpinning the desire to use ultrasound for the diagnostic imaging of musculoskeletal injury in children.

Ultrasound scanning is becoming a well used modality in the ED in terms of FAST, AAA scanning, vascular access, nerve blocks and localisation of foreign bodies. Therefore, many ED doctors are confident using the probes and interpreting different scans and many ED have purchased ultrasound machines.

Any reduction in unnecessary radiation is welcome.

There is a trend to making the paediatric patients’ ED journey as fear-free as possible. Most ED have dedicated paediatric areas and staff (sometimes including play specialists) and endeavour to keep contact with adult patients to a minimum. However, they do not usually have dedicated paediatric radiology areas. Therefore, any method of obtaining diagnostic imaging in the paediatric area would be welcome.

Finally, time is always a constraint—if a patient can be seen and given a diagnosis without waiting for a porter to take them to the radiology department, wait for x ray, and then wait for transport back, they are unlikely to cause a problem in terms of time spent in the ED.

The four papers have similarities in study design. They are prospective cohorts comparing a new diagnostic test (ultrasound scan for fracture detection) against a gold standard of x ray. They are all fairly small numbers—although 224 suspected fractures were scanned by Hubner et al, not all of these were the forearm fractures that this review is interested in—and are highly selected groups. Appropriately, all the authors exclude: open fractures, when ultrasound would not be appropriate due to pain, possible risk of infection and the need for operative management in the theatre; neurovascular compromise—when manipulation under anaesthesia without previous imaging may be required, and injuries with possible associated elbow injuries, in which more complex anatomy due to differences in epiphysis closure may make an ultrasound scan difficult to interpret.

However, the populations were generally recruited as convenience samples, allowing for the introduction of selection bias. There is also widespread variation in the ultrasound experience of the doctors carrying out the scans in each study, ranging from a consultant radiologist, to surgeons with vast previous scanning experience, to ED doctors with 2 h teaching on ultrasound.

A final problem with all the studies is a lack of longer-term follow-up, for example to see if any of those patients with false-positive ultrasound scans showed callus formation later, to prove a missed fracture on x ray.

Interestingly, despite the heterogeneity of the studies, they all show the sensitivity of ultrasound to be high varying from 91% to 100% and specificity from 69% to 100%. However, a larger study is needed to corroborate these figures and show that any missed fractures are not clinically significant.

At present, ultrasound-guided manipulation under anaesthesia shows promise for those units who perform this within the ED.

Editor Comment

c/w, compared with; ED, emergency department; ID, identification; PED, paediatric emergency department; MUA, manipulation under anaesthesia; USS, ultrasound scan.

Clinical Bottom Line

Although promising, there is not enough evidence at present to advocate the use of ultrasound over x ray for the diagnosis of paediatric forearm fractures. A further large positive study may well tip the balance in favour of ultrasound in a wellselected population of children with closed, neurovascularly intact injuries.

References

1. Chen L, Kim Y, Moore CL. Diagnosis and guided reduction of forearm fractures in children using bedside ultrasound. Pediatr Emerg Care 2007;23:528–31.
2. Hubner U, Schkict W, Outzen S, et al. Ultrasound in the diagnosis of fractures in children. J Bone Joint Surg (Br) 2000;82-B:1170–3.
3. Patel DD, Blumberg SM, Crain EF. The utility of bedside ultrasonography in identifying fractures and guiding fracture reduction in children. Pediatr Emerg Care 2009;25:221–225.
4. Williamson D, Watura R, Cobby M. Ultrasound imaging of forearm fractures in children: a viable alternative? J Accid Emerg Med 2000;17:22–4.