ABC Classification System ： Establishment and Preliminary Evaluation of CT-based Classification for Distal Radius Fracture

Abstract

Objective Establish a new classification system of distal radius fracture based on computed tomographic (CT), and evaluate its reliability and reproducibility preliminarily, and provide a new theoretical reference for clinicians to use the clinical classification system. Methods The imaging data and clinical data of 204 inpatients with distal radius fractures during 6 years from January 1, 2014 to January 1, 2019 in orthopaedic department were analyzed retrospectively and classified based on CT. Three observers evaluated the image data of 48 randomly selected cases based on CT at different time nodes of T1 and T2. Cohen's kappa was used to calculate the consistency. Results Among 204 cases, there were 12 cases of type A, including 6 cases of type A1, 4 cases of type A2 and 2 cases of type A3. There were 6 cases of type B, including 2 cases of type B1, 2 cases of type B2 and 2 cases of type B3. There were 186 cases of type C, including 32 cases of type C1, 127 cases of type C2 and 27 cases of type C3. There was no significant difference in Disabilities of the Arm, Shoulder and Hand (DASH), Patient-Rated Wrist Evaluation(PRWE) and VAS scores among all types (P > 0.05). The results of interobserver reproducibility were kappa = 0.985, ICC = 0.984 in the first evaluation, kappa = 0.986, ICC = 0.986 in the second evaluation. The results of intraobserver reproducibility were O1 = 0.991, O2 = 0.991, O3 = 0.989 respectively. Conclusions The new classification system of distal radius fracture based on CT has theoretical and practical significance for incision selection, fracture reduction and internal fixation. ABC typing system is clear, comprehensive, easy to understand and remember. Moreover, it has higher interobserver reliability and intraobserver reproducibility than other systems reported at present.