Use of Digital Tomosynthesis in Assessing Accurate Medial Epicondyle Fracture Displacement as Compared With Conventional Radiography and Computed Tomography

Abstract

Introduction: Medial epicondyle fracture displacement is notoriously difficult to determine on conventional radiography, and follow-up computed tomography (CT) is often obtained to measure precise displacement. Another option for fracture characterization is digital tomosynthesis (DT), a technology providing high in-plane resolution of bony anatomy by acquiring multiple low-dose images in a linear arc. Advantages of DT include lower radiation exposure and lower cost than CT, rapid image acquisition, and a similar patient experience to conventional radiography. The digital application of tomosynthesis is relatively new and is integrated as an add-on feature with modern radiography equipment. This study compares DT, CT and conventional radiography for measurement accuracy in medial epicondyle fractures with the goal of determining relative accuracy in measuring medial epicondyle fracture displacement. Methods: Medial epicondyle fractures were created in 5 cadaveric elbow specimens. Each specimen was imaged with conventional radiography, DT, and CT. True displacement measured by digital calipers was compared with “measured” displacement for each image acquisition. CT images included axial, sagittal, and coronal reformats. DT images of the elbow included anteroposterior (AP) longitudinal and transverse, lateral longitudinal and transverse, and axial longitudinal and transverse. Conventional radiographs included AP, lateral, and axial distal humerus images. Four physicians reviewed all images 3 months later. Each reviewer independently measured maximum apparent fracture displacement to the nearest 0.1 mm. Measurement accuracy was calculated as percent difference [(measured displacement−actual displacement)/actual displacement] for each acquisition. Mean, median, and SD for measurement accuracy were calculated. Two-tailed paired t tests were performed on each acquisition to compare the measurement accuracy. Results: Compared with conventional radiographs, accuracy of DT was superior in AP longitudinal ( P =0.03), AP transverse ( P =0.01), axial longitudinal ( P =0.0001), and axial transverse projections ( P =0.001). Accuracy of CT was superior to conventional radiography in the AP projection ( P =0.03), but was equivalent in the axial projection ( P =0.9). Accuracy of CT was similar to DT in AP longitudinal ( P =0.6), AP transverse ( P =0.5), and axial longitudinal projections ( P =0.07). Accuracy of DT in the axial transverse projection was superior to CT ( P =0.03). Conclusion: DT is more accurate than conventional radiography (both AP and axial views) and as accurate as CT in assessing millimeters of displacement of medial epic...

Use of Digital Tomosynthesis in Assessing Accurate Medial Epicondyle Fracture Displacement as Compared With Conventional Radiography and Computed Tomography

“…Given this ambiguity, CT imaging can inform the decision for surgical or nonsurgical treatment for some with medial epicondyle avulsion fractures. A 2019 study by Onay et al 1 showed that CT was "superior to determine the real amount of the fracture displacement and was relevant for treatment decision of pediatric medial epicondyle fractures". They also found "better interobserver agreement for axial CT scans relative to treatment decision".…”

“…We read with interest the recent publication by Livingston et al1 Livingston et al1 stated that computed tomography (CT) has become the preferred method for evaluating medial humeral epicondyle fracture (MHEF) displacement, quoting Onay et al,2 despite the latter authors2 neither having recommended routine use of CTs, nor having reported the use of CTs for the assessment of MHEFs after November 2014. Pezzutti et al’s3 systematic review contradicts Livingston et al’s1 statement, with 35 of 37 papers not having mentioned the use of CTs, one paper reported the use of CT in 8 patients of 32 MHEFs with an incarcerated fragment of which 4 CTs were not necessary to make the diagnosis and one paper which stated that internal oblique radiographs (IOXR) at least approximated the amount of true anterior displacement as seen on CT. None of the authors used digital tomosynthesis (DT). Livingston et al1 quoted Gottschalk et al,4 stating that conventional radiography has poor intraobserver and interobserver reliability.…”

“…Livingston et al1 did not provide any primary measurements/data so that the reader does not know if any of the provided statistics are clinically relevant. The authors’ box and whisker plot graph shows that the median accuracy of all 3 groups were close to 0 with the mean difference between “true” and measured displacement for all imaging modalities possibly having been <1 mm.…”

“…The axial radiographic measurements have a much lower interquartile and total spread and less outliers than DT and CT, which is reflected in the SDs, indicating that the radiographic measurements are the most reliable. Livingston et al1 did neither test intraobserver nor interobserver reliability for the examiners, nor the accuracy and reliability for the “true” displacement measurements of the specimens.…”

“…There are other potential specimen inaccuracies. The authors1 stated that all 5 specimens had varying degrees of anterior and inferior displacement and that the created fracture fragments were not solidly secured in place, which will result in different accuracies between specimens since the percentage accuracy depends on the amount of “true” displacement. Therefore, percentage accuracy might not be a reliable outcome measure, especially with the authors having used varying numbers of specimens for the imaging groups.…”