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Three Part Question

In [children with a history of trauma to the elbow] is [ultrasound useful when plain x-rays are inconclusive]at [detecting fractures around the elbow]?

Clinical Scenario

You have just seen a 6 year old child who is complaining of a painful left elbow after falling off a trampoline, plain x-rays are inconclusive and you wonder if an ultrasound has any value in detecting a fracture of the elbow joint in young children.

Search Strategy

Medline Search, 1960-2010

[exp ultrasonography$ OR sonography$ OR ultrasound$] AND [exp elbow $ OR Elbow joint OR elbow trauma$ OR elbow fracture$ OR painful elbow] AND [children$ OR child$ OR Paediatric$ ] AND [Role of ultrasound$ OR Ultrasonography$ OR sonography$] Limit to English articles.

Search Outcome

Search yielded a total of 250 results of which 14 where relevant to the original clinical question but 7 of the papers were not research based and not of sufficient quality and therefore excluded from the discussion, and the remaining 7 are discussed below.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Miles et al 1989 UNITED KINGDOM	Comparison of 40 elbows to demonstrate elbow fat pads, ages between 4 days and 71 years.	Cohort	Anterior and posterior fat pad demonstrated in 38 elbows with ultrasound. Failed to demonstrate it in a 4 day old infant.	Ultrasound can be used to demonstrate the position of the posterior fat pads which may be elevated with injury in the elbow.	20 years old. Adults included in study. Small study sample. Not directly related to clinical question.
Davidson et al 1994 USA	7 infants with clinical suspicion of elbow injury with inconclusive x-rays and one 10 year old child with fracture on x-ray	Cohort	Ultrasound showed 3 infants had transphyseal fractures of the humerus not clearly defined on plain x-rays.	Ultrasound provides valuable information in demonstrating fractures of the unossified cartilage when x-rays are inconclusive	No gold standard. Small study group
Hubner et al 2000 GERMANY	163 children (224 Bones) examined primarily by ultrasound followed by x-rays	Cohort study	Ultrasound detection of fractures varied depending on site of injury and was most reliable in the detecting fractures of the femur and humerus	Ultrasound has a Sensitivity of 91, 4% and specificity of 80%for detection of fractures	No gold standard e.g. MRI. Study was not specific for elbow injuries
Moritz et al 2008 Germany	653 patients from newborn to 17 years with a mean age of 4.4 years with nonspecific clinical signs of clinically indistinct fracture location were examined with ultrasound initially.	Cohort	Ultrasound is comparable to x-ray in detecting fractures, although this varied between the upper limbs and lower limbs. X-ray detected lower limb fractures better than on Ultrasound. Ultrasound was superior at detecting fractures of the clavicle compared to x-ray. 25 Upper limb fractures were diagnosed both on ultrasound and X-rays.	Sensitivity for ultrasound 92.9% and 93.2% for X-ray .	Not specific to the elbow joint as it included the broad term on upper limb. No gold standard.
Zhang et al 2008 China	9 children aged 2-9years with non displaced and minimally displaced lateral condyle fracture	Cohort study	Ultrasound used to demonstrate involvement of articular surface of trochlea in 6 and altered the treatment plan. Remaining 3 where no articular involvement found treated conservatively with good results on follow up.	Identifying injuries involving cartilaginous trochlea (not seen on plain films) via ultrasound, guided treatment and is less invasive than arthrography and less expensive than MRI.	Small study group. No Gold standard in all the cases since MRI used to confirm just 2 cases.
Zuazo et al 2008 France	14 children aged 5-15 with elbow trauma underwent ultrasound when radiographs showed an effusion but no fracture.	Cohort study	Detection of lipohaemarthrosis in 7 children on Ultrasound demonstrated a fracture on MRI.Simple haemarthrosis in remaining 7 children showed fracture on MRI in 1 child and no fracture in 6.	The detection of lipohaemarthrosis on ultrasound has 88%sensitivity and 100%specificity as an indirect indicator of intra articular fracture.	Small study size.
Cho et al 2010 Korea	25 Children younger than 15 years referred with trauma related pain and swelling of extremities.	cohort	Most common site for occult fractures was the elbow followed by the knee. On review of plain x-rays 13 showed soft tissue swelling and no bony abnormality ;on 6 of the elbow x-rays finding were unremarkable but ultrasound showed discontinuity of the bone surface.	On 6 of the x-rays of the elbow which were unremarkable, ultrasound showed discontinuity of the bone surface.	Study not entirely focused on the elbow joint alone. No gold standard (MRI) in every case.

Comment(s)

Despite the small population groups in most of the studies, the ability of ultrasound to demonstrate unossified cartilage, lipohaemarthrosis, discontinuity of the cortex and the position of fat pads provides useful information on detecting fractures which may not be visible on plain x-rays. The consequences of missing an elbow fracture in a child may result in long-term complications and unnecessary surgery. On the other hand unnecessary treatment in a cast when there is no fracture, requires follow up which adds to health care cost and waiting times at fracture clinics as well as being inconvenient for both child and parent. Given that ultrasound is less expensive and more readily available than MRI , it serves as a useful additional imaging modality available to evaluate suspected elbow fractures in children when plain film x-rays are inconclusive.

Clinical Bottom Line

Ultrasound appears to be a useful adjunct in evaluating clinically suspected fractures of the elbow in children when x-rays are inconclusive.

References

1. Miles KA and Lamont AC Ultrasonic demonstration on the elbow fat pads Clinical Radiology 1989; 40:602-604
2. Davidson RS, Markowitz RI, Dormans J et al Ultrasonographic Evaluation of the elbow in Infants and Young children after suspected trauma The journal of bone and Joint Surgery 1994; 76A: 1804-1813
3. Hubner U,Schlicht W, Outzen S Ultrasound in the diagnosis of fractures in children The journal of joint and bone surgery 2000; 82: 1170-1173
4. Moritz JD,Berthold LD,Soenksen SF,Alzen GF Ultrasound in diagnosis of fractures in children: unnecesary harassment or useful addition to X-ray? European journal of ultrasound 2008;29(3):267-274
5. Zhang JD, Chen H. Ultrasonography for non displaced and mini displaced humeral lateral condyle fractures in children Chinese Journal of Traumatology 2008;11(5) : 297-300
6. Zuazo I, Bonnefoy O,Tauzin C. Acute elbow trauma in children:role of ultrasonography Pediatric Radiology 2008 ; 38: 982-988
7. Cho K, Lee S,Lee Y,Suh K Ultrasound diagnosis of either an occult or missed fracture of an extremity in paediatric aged children Korean Journal of Radiology 2010; 11:84-94