A retrospective evaluation of reliability and reproducibility of Arbeitsgemeinschaftfür Osteosynthesefragen classification and Fernandez classification for distal radius fracture

Abstract This is a retrospective evaluated. The objective of this study was to test the interobserver reliability and intraobserver reproducibility of fracture classification with Arbeitsgemeinschaftfür Osteosynthesefragen (AO) system and Fernandez system used by 5 senior orthopedic surgeons. Anteroposterior and lateral radiographs of 160 patients hospitalized for displaced distal radius fracture were examined. Independently, 5 orthopedic surgeons evaluated the radiographs according to 2 different distal radius classification systems (3 types of results). Three statistical tools were used to measure interobserver reliability and intraobserver reproducibility. The intraclass correlation coefficient and kappa coefficient (k) were used to assess both interobserver and intraobserver agreement of AO and Fernandez. Kappa value indicated poor agreement (<0), slight (0–0.20), fair (0.21–0.40), moderate (0.41–0.60), good (0.61–0.80), and perfect (0.81–1.00). The intraobserver reproducibility of AO system (9 types) and Fernandez system were moderate with a value of 0.577 and 0.438. The intraobserver reproducibility of AO system (27 subtypes) was 0.286. The interobserver reliability of AO system (9 types) was moderate with a value of 0.469 and that of Fernandez was moderate with a value of 0.435. The interobserver reliability of AO system (27 subtypes) was 0.299. Neither of the 2 systems can give us a satisfactory agreement between interobserver reliability and intraobserver reproducibility. In AO system, the interobserver reliability and intraobserver reproducibility of the 9 types decreased with the increase of subgroups.