Reliability and reproducibility of classification of distal ulnar fractures using cone beam computed tomography...

Distal ulnar fractures (DUFs) remain under-investigated, primarily due to limited statistical power resulting from the low incidence. The present classification systems are difficult to use and are not validated for new radiological methods such as cone beam computed tomography (CBCT). We aimed to analyze the reliability and reproducibility of the 2 classification systems, Arbeitsgemeinschaft für Osteosynthesefragen foundation/Orthopaedic Trauma Association (AO/OTA) and Biyani, for fractures of the distal ulnar head and neck using CBCT images.

76 patients with DUF who underwent a CBCT scan during the years 2016-2022 were included retrospectively. The CBCT images were reviewed twice by 6 observers of different medical specialties and levels of experience. All fractures were classified according to AO/OTA and Biyani. The reliability and reproducibility of each classification system were analyzed using kappa value analysis.

The reliability was fair to moderate for AO/OTA, Light's ĸ 0.41 (95% confidence interval [CI] 0.38-0.45) and moderate for Biyani, Light's ĸ 0.45 (CI 0.42-0.49), and the reproducibility was substantial for both AO/OTA, mean ĸ 0.65 (CI 0.49-0.80), and Biyani, ĸ 0.69 (CI 0.60-0.79).

Both existing classification systems were perceived to be difficult to use and do not match existing fracture patterns. Using CBCT images, they both showed substantial reproducibility but not satisfactory reliability for clinical use.