Inter- and intra-observer variability of the AO/OTA classification for sternal fractures: a validation study

Recently, a new classification system for sternal fractures has been published in the Journal of Orthopedic trauma by the Arbeitsgemeinschaft für Osteosynthesefragen (AO) foundation and the Orthopaedic Trauma Association (OTA). The aim of this study was to evaluate inter- and intra-observer variability of the AO/OTA classification for sternal fractures.

Twenty multidetector computed tomography (CT) scans of patients with sternal fractures were classified independently by six senior and six junior orthopedic trauma surgeons of two level-1 trauma centers. Assessment was done on two occasions with an interval of 6 weeks. The kappa value was calculated to determine variability.

The inter-observer variability of the AO/OTA classification for sternal fractures showed fair-to-moderate agreement (kappa = 0.364). There was no significant difference between junior and senior surgeons. Analyses of the separate components of the classification demonstrated that agreement was lowest for classifying fracture type within the sternal body (kappa = 0.319) followed by manubrium (kappa = 0.525). The intra-observer variability showed moderate agreement with a mean kappa of 0.414.

The inter- and intra-observer variability of the AO/OTA classification for sternal fractures shows fair-to-moderate agreement. The overall performance of the classification might be improved with minor modifications.

Diagnostic cross-sectional study (level I).