Diagnostic accuracy of ultrasonography for diagnosis of elbow fractures in children

Diagnostic accuracy of ultrasound versus X-ray for distal forearm fractures in children and adolescents: a systematic review and meta-analysis

PURPOSE

Utilizing ultrasound for the detection of distal forearm fractures in children presents a potential safe and radiation-free alternative compared to X-ray.

METHODS

A systematic review was undertaken to compare the diagnostic accuracy of ultrasound in detecting distal forearm fractures in children with X-ray imaging within the period spanning January 2010 to August 2023. The electronic databases MEDLINE and Cochrane CENTRAL were utilized for data retrieval. The QUADAS-2 tool was employed to assess the quality of the included studies. Subsequent statistical analysis was performed to calculate pooled sensitivity and specificity, positive and negative likelihood ratios, as well as the diagnostic odds ratio.

RESULTS

Our meta-analysis included seventeen studies, encompassing a total of 2003 patients, 2546 ultrasound scans, and 1203 fracture cases as identified by the reference test (X-ray). The pooled sensitivity and specificity were 0.96 (95% CI: 0.93-0.98) and 0.96 (95% CI: 0.89-0.98), respectively. The positive likelihood ratio was 13.40 (95% CI: 7.97-21.50), the negative likelihood ratio was 0.06 (95% CI: 0.04-0.1), and the pooled diagnostic odds ratio was 209 (95% CI: 92.20-412.00). Our statistical analysis revealed low heterogeneity within our studied cohort.

CONCLUSIONS

Our study indicates that ultrasound exhibits exceptionally high accuracy in the detection of distal forearm fractures in children and adolescents. It can be employed safely to either confirm or rule out a fracture, thus circumventing the need for potentially harmful radiation exposure in this vulnerable population. Future research endeavors should focus on establishing a universally accepted protocol for training and scanning methods to standardize practices and eliminate disparities in diagnostic procedures.

Extra-capsular floating fat at the extremity: a review

Extra-capsular floating fat may present in a variety of non-articular locations at the extremity. Manifestation of floating fat or fat-fluid level(s) outside of a joint is a marker of trauma or infection. Recognizing radiologic sign(s) of extra-capsular floating fat can aid radiologists to provide an informed differential diagnosis and facilitate clinical care. This review discusses the etiology, mechanisms, and imaging appearance of extracapsular floating fat in specific anatomic and non-anatomic locations at the extremity.

Effectiveness of ultrasonography performed at the emergency department for pediatric elbow trauma cases

BACKGROUND

Two-way direct radiography is the first-choice imaging method for pediatric patients presenting to the emergency department with elbow trauma. Although, unlike radiography, ultrasonography (US) is not used routinely, studies show that US can be used in the diagnosis of fractures in pediatric patients.

METHODS

In this single-center prospective observational study, patients under the age of 18 who presented to the emergency department after sustaining elbow trauma constituted the population of the study. Findings of the posterior fat pad sign using bedside US and the result obtained by seven-point assessment of the bone cortex were compared with the final diagnosis.

RESULTS

Of the 128 patients enrolled in the study, 6 patients were excluded due to various reasons. Seventy (57.4%) patients were male, and median age was 7.7 years. On examining the final diagnosis of the patients at the emergency department, fracture diagnosis was observed in 39 patients (32%). It was determined that fracture diagnosis for 94.9% of the patients included in the study could be achieved using US (in the presence of at least the fat pad sign and/or direct findings of fracture based on the seven-point assessment).

CONCLUSION

US should be considered as a diagnostic tool in cases of pediatric elbow traumas owing to its high sensitivity and negative predictive value. US, which is reproducible, ionizing radiation-free, and can be performed at the bedside, can considerably reduce unnecessary radiography in low-risk patients when evaluated along with physical examination findings among patients in the pediatric age group presenting with elbow trauma. We believe that the result of our study will contribute to patient care practices.

2D vs. 3D Ultrasound Diagnosis of Pediatric Supracondylar Fractures

Supracondylar fractures are common injuries in children. Diagnosis typically relies on radiography, which can involve long wait times in the ED, emits ionizing radiation, and can miss non-displaced fractures. Ultrasound (US) has the potential to be a safer, more convenient diagnostic tool, especially with new highly portable handheld 2D point of care US (POCUS). This study aimed to determine the reliability of 2D POCUS for the detection of supracondylar fractures and elbow joint effusions, to contrast the accuracy of 2D POCUS vs. 3DUS vs. radiographs, and to determine whether blinded image interpretation could produce similar results to non-blinded real-time imaging. Fifty-seven children were scanned with 2D POCUS and 3DUS on the affected elbow. US scans were then read by three blinded readers, and the results were compared to gold-standard radiographs. Compared to a gold standard of 30-day radiographic diagnosis, readers of 2D POCUS detected supracondylar fracture and effusion with sensitivities of 0.91 and 0.97, respectively, which were both higher than with 3DUS. Inter-rater reliability of fracture detection was moderate for 2D POCUS (k = 0.40) and 3DUS (k = 0.53). Consensus sensitivities, although high, were lower than reports from some non-blinded studies, indicating that clinical presentation serves as an important factor in detection rates. Our results from consensus US diagnosis support the validity of using 2D POCUS in children for supracondylar fracture and elbow effusion diagnosis.

Children With Elbow Injuries and Sonographic Elevated Posterior Fat Pad but No Identifiable Posterior Fat Pad on Lateral Radiographs: A Case Series

Point of Care Ultrasound (POCUS) is used to evaluate the injured pediatric elbow. Standard of care, however, remains radiography. POCUS performed in the setting of normal radiographs have been obtained may demonstrate radiologic occult lipohemarthrosis indicative of occult fracture. We reviewed our pediatric emergency department (PED) POCUS archive for lipohemarthrosis, and then isolated those cases with normal elbow radiography. Radiography was deemed to be normal per the interpretation of the treating PED physician, and was reviewed for this series by an experienced ABR board certified pediatric radiologist. Fracture on POCUS was defined as fracture line or lipohemarthrosis in a posterior sagittal or transverse view of the distal humerus. Fracture was confirmed by signs of cortical healing on follow-up radiography, or clinical course consistent with fracture as documented by an orthopedist. We identified four children with elbow fractures who had no fracture line or elevated posterior fat pad on radiography but demonstrated lipohemarthrosis on POCUS. POCUS may elicit evidence of fracture even after normal radiography, and POCUS findings suggesting occult fracture may allow for more effective guidance on discharge.