Ultrasound Evaluation of Pediatric Orthopaedic Patients

Jody Litrenta, MD; Karim Masrouha, MD; Amy Wasterlain, MD; Pablo Castaneda, MD

Disclosures

J Am Acad Orthop Surg. 2020;28(16):e696-e705. 

In This Article

Fractures

Fractures are common findings in pediatric patients presenting to the ED. Traditionally, fracture diagnosis and confirmation of reduction is performed with the use of radiographic imaging. To further enhance reduction accuracy, some practitioners use fluoroscopy during the reduction maneuver and splint or cast application. Recent studies have found that sonographic imaging is an effective diagnostic test that can be used to identify fractures without exposing the patient to radiation.[2–4]

A study by Chen et al[2] evaluated 48 patients between the ages of 2 and 21 years in the pediatric ED with forearm fractures. For each patient, four views were obtained using ultrasonography and radiographs. Ultrasonography had a 97% sensitivity and 100% specificity in detecting pediatric forearm fractures. Of those 48 patients, ultrasonography was able to correctly identify the fracture location for 46 patients. In two patients, ultrasonography had identified fractures of the metaphysis of the radius but failed to diagnose ulnar styloid fractures. Nonetheless, the importance of detecting ulnar styloid fractures is minimal because these are generally not clinically significant injuries and do not change the management. Ultrasonography could therefore be used as a rapid screening tool to quickly identify patients with fractures that may warrant further radiographic imaging. Patients with negative ultrasonography examinations could be reassured that a fracture is unlikely and spared the radiation associated with radiographs.

Clavicle fractures are also successfully diagnosed with ultrasonography. A study by Cross et al[3] evaluated 100 pediatric patients in the ED, presenting with pain around the shoulder or clavicle pain, who would be obtaining a radiograph as part of his or her clinical workup. They observed a 95% sensitivity and 96% specificity for diagnosing clavicle fractures in pediatric patients with ultrasonography. Ultrasonography was unable to identify fractures in two patients, and both had nondisplaced fractures of the clavicle visible on the radiograph.[3]

In addition to the diagnosis, ultrasonography can be used as a tool to assist in fracture reduction. Fluoroscopy is often used to aid in accurately reducing and immobilizing forearm fractures. The use of fluoroscopy increases the chance that the initial reduction attempt is adequate, thereby limiting the possibility of repeated reduction attempts and subsequent number of trips to the radiology suite.[5] However, using fluoroscopy during reduction has disadvantages as well. Stand-alone EDs and smaller facilities may not have access to a C-arm. In facilities that do have a C-arm, obtaining and transporting the machine can take considerable time and effort. Maneuvering the machine while manipulating the fracture can also be cumbersome and difficult and may require an assistant. Fluoroscopy also exposes both the patient and the practitioner to additional radiation. In one study of pediatric forearm fractures reduced with a mini-C-arm, the average radiation exposure was 109 millirad (mR).[6] By comparison, a flat plate forearm radiograph exposes a patient to 20 mR of radiation, and the average radiation exposure of an individual is 620 mR per year. This illustrates that even mini-C-arm radiation exposure is not insignificant. Using ultrasonography to assist with reduction can therefore be a useful alternative to fluoroscopy.

For a forearm fracture, the patient is positioned supine with the fingers suspended using finger traps. Ultrasonography is used to obtain a baseline understanding of the fracture pattern in two planes. Each ultrasonography view is analogous to one cut of a CT scan. For example, when the probe is placed longitudinally along the radial aspect of the forearm, this corresponds to a midcoronal CT image or an AP radiograph (Figure 1). When the probe is moved to the dorsum of the wrist, this is analogous to sagittal CT cut or a lateral radiograph. Ultrasonography can then be used in a dynamic fashion to visualize the reduction obtained during the reduction maneuver. A disadvantage of using ultrasonography for fracture reduction is that it cannot be used during splint or cast application. However, we have found that ultrasonography obtained after reduction but before cast application corresponds well to postcasting radiographs. Similarly, Patel et al[4] have also reported a 92.3% agreement between ultrasonography and radiographs for confirming the adequacy of reduction.

Figure 1.

Radiograph demonstrating the technique for using ultrasonography to assist with reduction of a pediatric distal radius fracture. A, The ultrasonography probe is positioned longitudinally along the radial aspect of the forearm. B, The corresponding ultrasonography image produced by the probe is analogous to a coronal CT cut, demonstrating the radius superficially and the ulna deeper relative to the probe. C, Postreduction AP radiograph corresponding to the ultrasonography view reveals adequate reduction.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....