Can Ultrasound Accurately Diagnose fractures?

Injury ⋅ April 30, 2020

Diagnosis of avulsion fractures of the distal fibula after lateral ankle sprain in children: a diagnostic accuracy study comparing ultrasonography with radiography Takakura et al. BMC Musculoskeletal Disorders (2020) 21:276

Radiography is currently the gold standard for the diagnosis of fractures. However, diagnosis of avulsion fracture is difficult using standard radiographs of the ankle as more than half of the fractures are not visible on anteroposterior and lateral views.

Anterior talofibular ligament view of the ankle. An avulsion fracture of the distal fibula is visualized (arrow)

Specialized radiographic projections, such as the ATFL and CFL views, can visualize avulsion fractures effectively, but at the cost of additional expense and radiation exposure.

Although radiography uses low-dose radiation, exposure to this hazard may have a cumulative effect on pediatric patients because the growing bone is vulnerable to radiation injury.

Furthermore, small fracture fragments and chondral avulsions may not be detected even if these projections are used. The Ottawa Ankle Rules are commonly used clinical examination rules to identify patients with ankle injuries that do not require radiographic examination.

Although the rules have high diagnostic accuracy in excluding ankle fractures, their sensitivity is lower in children than in adults.

Therefore, a non-invasive and high accuracy diagnostic tool is needed for the diagnosis of avulsion fracture in children.

With recent improvements in image quality, ultrasonography has been used as a first-line imaging modality for pediatric foot and ankle injuries.

Sonographic examination of ankle trauma can be immediately performed in an outpatient clinic and reduces the need for radiography.

Furthermore, ultrasonography can also visualize small avulsion fractures and unossified epiphyses.

Sonographic image of the longitudinal view of the anterior talofibular ligament. a Avulsion fracture (arrow) at the fibular insertion of the anterior talofibular ligament (arrowhead), b Subfibular ossicle (arrow), c Anterior tibiofibular ligament injury (arrow), d No osseous or ligamentous injury (arrow)

Thus, ultrasonography can often reveal a fracture that may overlooked on standard radiographs.

These characteristics make it particularly suitable for the diagnosis of avulsion fractures of the distal fibula.

Additionally, ultrasonography can visualize ligament injuries that cannot be evaluated by radiographs.

However, the diagnostic accuracy of ultrasonography in detecting avulsion fractures of the distal fibula has not been clarified or compared with that of radiography.

This new study concludes that ultrasonography, performed by experienced examiners, has a high diagnostic accuracy, which is comparable to that of radiography for the diagnosis of avulsion fracture of the distal fibula.

Ultrasonography may therefore be used as an alternative to radiography for lateral ankle sprain in children.

The full paper is open access and may be read here.