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Reference: Snelling et al. Ultrasonography or radiography for suspected pediatric distal forearm fractures. New England Journal of Medicine June 2023

Date: July 19, 2023

Guest Skeptic: Dr. Casey Parker is a Rural Generalist that includes in his practice emergency medicine, anesthesia, and critical care. He is also a fully-fledged ultrasonographer. Casey currently splits his time between Broome, a small rural hospital in the remote Kimberley region of Western Australia, and a large tertiary ED in sunny Perth. He has been a guest skeptic on the SGEM multiple times. He is also the creator of the amazing #FOAMed website, Broome Docs.

Dr. Casey Parker

Case: It is a steady Saturday afternoon in your rural emergency department (ED). The triage nurse calls you to have a look at a child who has arrived with his parents in ED after falling from a bouncy castle at a birthday party.  He is six years old and appears to be in pain with his left wrist swaddled in an ice pack.  He tells you that he was attempting “a double backflip like Spiderman” when he landed heavily on the outstretched hand – this happened about an hour ago. Clinically there is some swelling and tenderness over the distal radius but no deformity.  He has good perfusion and no neurological symptoms in the hand. Because it is a small, rural ED there is no radiographer on site but they can be called in if we would like to get an X-ray…. or there is a portable bedside ultrasound machine in the next room ready to go. The child’s mother tells you that the X-ray tech was also at the party having a great time with her children. So, the question is: should we call in our x-ray tech in and disrupt her party fun or just use the ultrasound machine to diagnose this possible fracture?

Background: We have covered pediatric wrist fractures a few times on the SGEM. This includes SGEM#19 way back in 2013 reporting a bandage wrap is a safe alternative to traditional casting for children with greenstick fractures. More recently, the amazing Dr. Tessa Davis covered the FORCE trial on SGEM #372 which looked at buckle fractures and compared immobilization in a cast or splint vs. a soft bandage and they found no difference in pain scores or functional outcomes.

The use of bedside ultrasound to diagnose uncomplicated wrist injuries in children has been studied in several diagnostic prospective, observational trials to compare its accuracy to traditional plain film X-rays [1-5].  Most of these trials have shown diagnostic sensitivity and specificity above 90% when compared to X-ray as a gold standard.  This same research team from Queensland in Australia have also published a paper describing the learning curve for novices in detection of forearm fractures in kids [6]. 

In 2022 Mobasseri et al published a review of 9 such diagnostic studies and concluded that from an orthopedic perspective that the accuracy was not acceptable, the lack of a randomized controlled trial meant that there was not enough data to support the use of ultrasound over X-ray as an initial diagnostic test [7].

There have been no randomized trials that have compared the patient-centered, functional outcomes after a wrist injury based upon the choice of initial diagnostic test modality.

Clinical Question: In children with non-deformed distal forearm injuries, does the use of ultrasound as an initial diagnostic test result in inferior functional outcomes?

Reference: Snelling et al. Ultrasonography or radiography for suspected pediatric distal forearm fractures. New England Journal of Medicine June 2023

  • Population: Children between 5 and 15 years of age who presented to the ED with an isolated, acute, clinically non-deformed, distal forearm injury for which imaging for a suspected fracture was indicated
    • Excluded: obvious angulation/deformity (soft tissue swelling allowed), injury >48hr prior, external X-rays obtained, known bone disease, concern for non-accidental trauma, additional injuries requiring X-rays, congenital forearm abnormality, no credentialed clinician available, developmental delay or behavior prohibiting clinical assessment
  • Intervention: Bedside ultrasound carried out and interpreted by a trained clinician (doctors, nurse practitioners and physiotherapists)
  • Comparison: X-ray
  • Outcome: 
    • Primary Outcome: Functional outcome at four weeks (± 3 days) post injury as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) score
    • Secondary Outcomes: PROMIS scores at 1 week and 8 weeks post injury.  
      • They also analyzed the children by age cohorts 5 to 9 years and 10 to 15 years old
      • There was also an analysis of the diagnostic accuracy of the ultrasound vs. X-rays.
      • Satisfaction at 4 and 8 weeks (5-point Likert scale with lower scores indicating greater satisfaction)
      • Pain at 1, 4, and 8 weeks using the FACES pain scale
      • Frequency of complications
      • Frequency of radiography
      • Length of stay and treatment time in the ED
  • Trial: Multicenter, open-label, noninferiority, randomized, controlled trial

Authors’ Conclusions: “In children and adolescents with a distal forearm injury, the use of ultrasonography as the initial diagnostic imaging method was noninferior to radiography with regard to the outcome of physical function of the arm at 4 weeks.”

Quality Checklist for Randomized Clinical Trials:

  1. The study population included or focused on those in the emergency department. Yes
  2. The patients were adequately randomized. Yes
  3. The randomization process was concealed. Yes
  4. The patients were analyzed in the groups to which they were randomized. Yes. 
  5. The study patients were recruited consecutively (i.e. no selection bias). No. 
  6. The patients in both groups were similar with respect to prognostic factors. Yes
  7. All participants (patients, clinicians, outcome assessors) were unaware of group allocation. No
  8. All groups were treated equally except for the intervention. No
  9. Follow-up was complete (i.e. at least 80% for both groups). Yes 
  10. All patient-important outcomes were considered. Yes
  11. The treatment effect was large enough and precise enough to be clinically significant. No
  12. Financial conflicts of interest.  No

Results: They randomized 270 patients. Primary outcome data at 4 weeks was available for 130 patients in the ultrasonography group and 132 patients in the radiography group. The average age of patients was around 10 years with 90% of them being right hand dominant. There were slightly more male patients in the radiography group (57% vs 50%). Most common mechanism of injury was fall on outstretched hand.

Key Results: Ultrasonography was noninferior to radiography as a diagnostic test in terms of functional outcomes at 4-weeks following wrist injury in children.

Primary Outcome: 

Secondary Outcomes:

  • Functional outcomes were not statistically different at each of the time points.
  • Ultrasound did appear to be better than X-ray in terms of parental satisfaction, length of time in the ED and time away from school.
  • Although the patients randomized to ultrasound initially had about one third as many X-rays on the initial visit, there was a similar number of x-rays performed at follow-up visits

Patient Oriented Outcomes:

We were pleasantly surprised at all the patient-oriented outcomes in this study: function, pain, satisfaction of both caregivers and patients, missed school days. 

We were not quite sure about the satisfaction rating. This was rated on a Likert scale of 1 to 5 and they found that there was greater parent/caregiver satisfaction in the ultrasonography group at follow-up at 4 weeks and 8 weeks. But why? Were they happy because the person performing the ultrasound explained things nicely? Were they happy because ultrasound didn’t expose the child to radiation? Were they happy simply because someone spent more time with them while performing the ultrasound?

Selection Bias:

One of the exclusion criteria for this study was obvious angulation or deformity on clinical exam. There is a degree of subjectivity in determining deformity. Additionally, soft tissue swelling was allowed. Would we all agree? This study did end up including some patients with angulated fractures.

Clinically deformed wrists are in a way easier. We know that they are going to be broken and might need manipulation.  So, by excluding this group the authors are selecting a cohort with more subtle injuries.  However, this is a subjective inclusion criterion.  It may not matter though as all the children got some form of imaging.

Clinical Significance of Injuries:

Forearm injuries occur on a spectrum from a little bone “bruise”, through a buckle and then the nasty dinner fork fractures.   We have learned from trials like the FORCE trial that there must be a point on this “injury spectrum” where interventions like plaster casts or splints will have no benefit over “do nothing care”.  

However, splints are not benign, so applying them to every kid with a tiny cortical breach will almost certainly result in unnecessary immobilization and some degree of temporary loss of function. There’s also the possibility that a poorly applied splint may cause skin breakdown. Or if the child gets the splint wet, it results in them coming back to the ED.

It may be that ultrasound is less sensitive than X-ray, but that this does not matter as the injuries we do not see on ultrasound are unlikely to benefit from immobilization. In this trial there were more splints placed on kids in the group who were X-rayed at the initial visit. However, the kids who were found to have a buckle or torus injury did receive a splint in this trial.  And yet there was no difference in functional outcomes. So, maybe it really does not matter what we do in the first instance?

The BUCKLED TRIAL and the FORCE trail were recruiting kids at the same time.  After the FORCE trial showed no difference between splint and a soft bandage it would be interesting to re-run this trial and not splint those kids with a simple buckle – maybe then they would do better in terms of function. 

There’s also a question of the denominator. How many children fell today that have a buckle fracture and were never brought or referred to the ED? Those kids were likely treated like they sprained their wrist and encouraged to get back to it, aka the “rub some dirt on it and go about your day” approach. So what is the true denominator of the population that fell and have a non-angulated fracture? We don’t know. 

If this study is setting the stage for potentially using ultrasonography to diagnose other pediatric fractures, we would also need buy-in from our orthopedic colleagues for this to be effective. It would not surprise me for them to still ask for formal X-rays.

It should be noted that in this trial US was actually more accurate than X-ray (table S2 in the appendix). The expert panel reviewed all the images there were only 2 changes to the final diagnosis in the US group whereas there were 7 changes to diagnosis in the X-ray group.  

Ultrasound Credentialing:

Trying to get the whole system of physicians, nurses, etc. all up to a standard where they can replicate this diagnostic accuracy is not so easy.  Although pediatric forearms are technically simple to scan, there are quite a few false positives with all those little growth plates and variants as kids grow. There is almost certainly a Hawthorne effect in play here. Enthusiastic trial participants are always going to be better than the average ED physician.

This trial group spent a lot of time teaching the clinicians, including didactic, scanning one another, models, proctored scans, logbooks and a final assessment to ensure competence before involvement in the trial. We are not sure how feasible this is depending on where you practice.

Especially in rural areas where US might be most pragmatic in its utility, staff turnover is often very high. So, it would be tough to compete with plain films reliability in this context.

Generalizability:

We applaud the authors for training so many of the ED team members in using ultrasound to assess for buckle fractures. We also think that the use of multiple types of ultrasound machines and probes makes this study more generalizable.

We are still not sure of its widespread implementation. In a rural practice location where X-ray may not be readily available or there is a significant delay, ultrasound seems like a very appropriate option.

If you practice in an academic institution or a location where getting an X-ray is not difficult. From a workflow perspective, X-rays are often already ordered in triage for a patient presenting with forearm pain after fall and sometimes the X-ray is done by the time the patient makes it from the waiting room into the ED. The authors did note that it did decrease triage to emergency department triage by 15 minutes, but this 95% confidence interval was wide and ranged from 29 minutes to 1 minute.

In larger hospitals with 24/7 access to radiography one might argue that if front-line clinicians are spending time on ultrasound, then we are just shifting the time cost from the imaging department back to the busy EM physicians and nurses.  

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We generally agree with the authors’ conclusion.

SGEM Bottom Line: Ultrasound may be an appropriate method for diagnosing fractures in clinically non-deformed distal forearm injuries when access to radiographs is a challenge.

Case Resolution: You decide to perform a bedside ultrasound after some oral analgesia. A small buckle fracture is seen just on the radial aspect of the forearm. There is no angulation or shortening. Given your knowledge of the FORCE trial you discuss the management options with the child’s parents (soft bandage or a splint). You agree on a soft bandage and give advice to the boy about impersonating Marvel characters over the next few weeks. The family return to the party 15 minutes after triage and share some cake with the very happy radiographer.

Clinical Application:  The use of bedside ultrasound to diagnose forearm injuries seems to be a reasonable diagnostic strategy.  This trial shows that there was no difference in important patient-oriented outcomes if we use this strategy in kids with clinically non-displaced injuries.

There is potential for implementation in primary care settings. Many primary care settings do not have easy access to X-ray but imagine being able to ultrasound a child with an arm injury and potentially save them an ED visit!

What Do I Tell the Parent? Your child has a buckle fracture on ultrasound.  Fracture means break or broken bone. This injury can be safely managed with either a bandage or a soft splint. However, he will need to avoid activities where he may reinjure his wrist for the next month.  We will give you medicine plan to control his pain. Our excellent orthopedic (broken bone) team will see your child in their clinic next week and discuss his progress.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.

References:

  1. Troxler D, Sanchez C, de Trey T, Mayr J, Walther M. Non-inferiority of point-of-care ultrasound compared to radiography to diagnose upper extremity fractures in children. Children (Basel). 2022;9(10):1496.
  2. Douma-den Hamer D, Blanker MH, Edens MA, et al. Ultrasound for distal forearm fracture: a systematic review and diagnostic meta-analysis. PLoS One. 2016;11(5):e0155659.
  3. Chaar-Alvarez, Frances M – Pediatr Emerg Care (2011) Bedside ultrasound diagnosis of nonangulated distal forearm fractures in the pediatric emergency department.pdf
  4. Snelling PJ, Jones P, Keijzers G, Bade D, Herd DW, Ware RS. Nurse practitioner administered point-of-care ultrasound compared with X-ray for children with clinically non-angulated distal forearm fractures in the ED: a diagnostic study. Emerg Med J. 2021;38(2):139-145.
  5. Rowlands, Rachel – J Emerg Med (2017) Bedside ultrasound vs x-ray for the diagnosis of forearm fractures in children.pdf
  6. Snelling PJ, Jones P, Moore M, et al. Describing the learning curve of novices for the diagnosis of paediatric distal forearm fractures using point-of-care ultrasound. Australas J Ultrasound Med. 2022;25(2):66-73.
  7. Mobasseri A, Noorifard P. Ultrasound in the diagnosis of pediatric distal radius fractures: does it really change the treatment policy? An orthopedic view. J Ultrason. 2022;22(90):e179-e182.