Evaluation of the Intraobserver and Interobserver Agreements of the New AO/OTA Classification for Fractures of the Trochanteric Region and the Femoral Neck

Objective In the present study, we investigated the intra and interobserver agreement of the new Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification for fractures of the proximal extremity of the femur. Methods One hundred hip radiographs were selected from patients who suffered fractures of the trochanteric region or femoral neck. Four orthopedists, fellowship trained hip surgeons, and four orthopedic residents evaluated and classified fractures according to the new AO/OTA system on two separate occasions. The kappa (k) coefficient was used to evaluate intra and interobserver agreement in the different steps of the classification, namely: type , group , subgroup , and qualifier. Results Hip surgery experts obtained almost perfect intraobserver agreement of type , substantial for group and, only moderate, for subgroup and qualifiers. The residents had lower performance, with substantial agreement for type, moderate for group , and reasonable for subgroup and qualifier. In the specialists' interobserver evaluation, there was also a gradual decrease in the agreement between type (almost perfect) and group (moderate), which was even lower for subgroup and qualifiers. Residents had a substantial interobserver agreement for type , moderate for group , and reasonable in the other branches. Conclusion The new AO/OTA classification for fractures of the trochanteric region and femoral neck showed intra and interobserver agreements considered appropriate for type and group , with a drop in the subsequent branches, that is, for subgroup and qualifier. Still, in relation to the old AO/OTA classification, there was an improvement in the agreements for subgroup.