The internal rotation traction radiograph does not improve the reliability in the AO classification system for pertrochanteric fractures. An inter- and intra-observer reliability assessment

Abstract

Introduction: The most universal method for classifying pertrochanteric fractures is the AO/OTA classification. These fractures are classified into different categories according to the features found in the anteroposterior radiograph of the hip. Anteroposterior radiograph of the hip with internal rotation traction can improve the characterization of the fracture. Inter- and intra-observer reliability in any classification is essential to achieve a homogeneous agreement for decision making. Our objective is assessing the overall reliability and by level of experience of the new AO/OTA classification of pertrochanteric fractures.

Materials and methods: A hospital registry was used to collect patients with pertrochanteric hip fracture who had anteroposterior radiograph of the hip with and without internal rotation traction. We selected six evaluators stratified by levels of expertise in orthopedic trauma, leaving three groups: advanced, intermediate and beginner. Radiographs were sent through electronic forms and inter- and intra-observer reliability was calculated using the kappa (K) statistic.

Results: 115 (one hundred fifteen) patients were included, each with their corresponding anteroposterior radiograph of the hip with and without internal rotation traction. Overall inter- and intra-observer reliability was moderate on both anteroposterior radiographs of the hip with and without internal rotation traction. Regarding the different levels of experience, the advanced level group reached a substantial inter- and intra-observer reliability in both anteroposterior radiographs with and without traction, while the rest of the groups with lower level of experience obtained a lesser reliability.

Conclusion: Our study found that the internal rotation traction x-ray did not improve the reliability of the new AO/OTA classification for pertrochanteric fractures, as assessed by inter- and intra-observer agreement, in either the overall group or in groups divided by experience level.

Keywords: AO/OTA classification; Hip fracture; Inter-observer; Intra-observer; Reliability; X-ray.