Reliability of the 2018 Revised Version of AO/OTA Classification for Femoral Shaft Fractures

Background: The Arbeitsgemeinschaft für Osteosynthesefragen (AO) and the Orthopaedic Trauma Association (OTA) classification system for diaphyseal fracture has been recently revised to refine and enhance the accuracy of fracture categorization. This study aimed to investigate the interobserver reliability of the new AO/OTA classification and to compare it with the older version in femoral shaft fractures. Methods: We retrospectively analyzed 139 patients (mean age, 43.8 ± 19.5 years; 92 men and 47 women) with femoral shaft fractures who were treated from 2003 to 2017. Four well-trained observers independently classified each fracture following the previous and revised AO/OTA classification system. We calculated the Fleiss kappa for the interobserver reliability. Results: The previous classification showed the kappa value of 0.580 (95% confidence interval [CI], 0.547–0.613), and the revised version showed 0.528 (95% CI, 0.504–0.552). Both the old and the revised versions showed moderate reliability. Conclusions: Our study highlights the moderate interobserver reliability of both the previous and new AO/OTA classification systems for diaphyseal femur fractures. These findings emphasize the importance of standardized systems in clinical decision-making and underscore the need for ongoing education and collaboration to enhance fracture classification.