How Reliable Are Digital Radiographs for Evaluating Intra-articular Displacement in Ankle Epiphyseal Fractures: Can Computed Tomography Be Eliminated?

Abstract

The amount of intra-articular displacement of the fracture is the main issue when deciding the treatment method between conservative or surgical means in intra-articular fractures. In this study, we aimed to determine the intraobserver and interobserver reliability of measuring intra-articular displacement and to compare the digital radiographic and computed tomographic (CT) evaluations in distal tibia intra-articular epiphyseal fractures. Thirty-seven patients with digital radiography and CT scans were included in the study. Four sets were prepared with these images. Two of four sets were prepared as ankle radiographs, and the other two sets were prepared with CT scan views. Five observers were asked to measure the intra-articular displacement of the fractures in millimeters and also to make a decision between displacement amounts over or under 2 mm. Intraclass correlation coefficient scores were calculated for evaluation of intraobserver reliability, and Fleiss kappa values were calculated for interobserver reliability evaluations. A value greater than 0.75 was accepted as excellent agreement; 0.75 to 0.40 as intermediate to good agreement; and below 0.40 as poor agreement. There were 15 Salter-Harris type 3, 13 Salter-Harris type 4, seven triplanar, and two Tillaux-Chaput fractures. Both intraobserver and interobserver reliabilities were slightly higher for CT scan evaluations. Amounts of displacement were found to be measured higher after CT scan evaluations other than radiographs. After the measurement of joint displacements on CT scans, it was observed that the measurements found below 2 mm on the digital radiograph measurement changed to greater than or equal to 2 mm in 16.4% of the patients. This study confirmed that digital radiographs cannot replace CT scans for the measurement of intra-articular displacement in ankle epiphyseal fractures.