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Three Part Question

In [children presenting with ankle injuries with normal plain radiography] can [ankle ultrasound scanning] be used to [ detect occult fractures]

Clinical Scenario

A child attends the emergency department with an acute ankle injury. Clinically they are tender over the ankle and either partially or non weight bearing. A fracture is suspected but the xray appears normal.
You wonder if the child could still have an occult fracture and wonder whether an USS would be of benefit for this child

Search Strategy

Medline and Embase using the Ovid interface – June 2012
Medline:(ankle$.ti,ab OR(ankle AND joint)) AND (ultrasound$.ti,ab OR ultrasonic$.ti,ab OR ultrasonography.ti,ab) Limit to: English Language and (Age Groups All Child 0 to 18 years)]

Embase: ((ankle AND joint).ti,ab OR ankle$.ti,ab) AND (ultrasound.ti,ab OR ultrasonic.ti,ab OR ultrasound$.ti,ab OR ultrasonography.ti,ab) Limit to: Human and English Language and (Human Age Groups Child unspecified age)]

Search Outcome

Medline revealed 144 papers and Embase 67 papers. Of these papers 6 were relevant but 3 were excluded as the data included both adults and children. 3 papers have been reviewed below

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Simanovsky et al 2009 Israel	41 children age 2 - 16 with negative ankle plain imaging but clinical suspicion of fracture	Prospective	Fracture detected by USS	12 fractures detected by ultrasound. All of clinical significance and requiring immobilisation Sensitivity 100% Specificity 96%	Low study numbers Plain images reviewed by both senior orthopaedic and senior radiologist prior to being enrolled for USS The findings were not compared to the gold standard which would be MRI Mentioned that USS was performed without causing pain but pain was not measured therefore cannot be quantified
Simanovsky et al 2005 Israel	20 children age 5 - 13 with ankle injury and negative plain imaging	Prospective	Fracture detected by USS	7 fractures detected through USS which were not picked up on plain imaging. All were non displaced and required immobilisation and follow up Sensitivity 100%. Specificity 100%	Same group of authors as previous study Low numbers in study (n=20) Uncertain if this is a subgroup of the study already listed Children only age 5 - 13
Farley, F et al. 2001 USA	14 children with ankle injury, negative plain radiography and open tibia - fibula physis	Prospective	Fracture detected by USS	2 physeal injuries detected both with associated ligamentous injury. Fractures defined as Salter-Harris type 1 injuries requiring immobilisation	Small study numbers Only open physis patients included in study

Comment(s)

Only 3 studies have looked at the diagnostic benefit of ultrasound scans in children with ankle injuries and normal plain x-ray. The studies show that where there is clinical suspicion of fracture but normal imaging a small proportion of fractures may be missed. Some of these fractures are type 1 Salter-Harris fracture and all require a period of immobilisation. Given the potential effect on growth plates and the absence of radiation with ultrasonography there is potential for more accurate diagnosis, including confirmation of ligamentous injury with ultrasound. However, it should also be considered that although ultrasound scanning is non-invasive its use may be limited by pain from the site of injury. The Simanovsky paper reported the procedure as painless, butthey did not use any formal pain scoring system during the assessment. This must be taken into consideration is ultrasound is to be used as an imaging modality in children with suspected ankle fracture.

Clinical Bottom Line

Ultrasound should be considered in children presenting to the emergency department with strong suspicion of ankle fracture (bony tenderness) where initial xray is normal

References

1. Simanovsky, N: Lamdan, R: Hiller, N et al. Sonographic Detection of Radiographically Occult Fractures in Pediatric Ankle and Wrist Injuries Journal of Pediatric Orthopaedics: 2009; 29(2);142-145.
2. Simanovsky, N: Lamdan, R: Hiller, N et al. Sonographic detection of radiographically occult fractures in paediatric ankle injuries. Pediatric Radiology 2005; 35(11); 1062-1065.
3. Farley, F et al. Ultrasound Examination of Ankle Injuries in Children