RESUMEN
BACKGROUND: Fractures of the proximal radius need to be classified in an appropriate and reproducible manner. The aim of this study was to assess the reliability of the three most widely used classification systems. METHODS: Elbow radiographs images of patients with proximal radius fractures were classified according to Mason, Morrey, and Arbeitsgemeinschaft für osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) classifications by four observers with different experience with this subject to assess their intra- and inter-observer agreement. Each observer analyzed the images on three different occasions on a computer with numerical sequence randomly altered. RESULTS: We found that intra-observer agreement of Mason and Morrey classifications were satisfactory (kappa = 0.582 and 0.554, respectively), while the AO/ASIF classification had poor intra-observer agreement (kappa = 0.483). Inter-observer agreement was higher in the Mason (kappa = 0.429-0.560) and Morrey (kappa = 0.319-0.487) classifications than in the AO/ASIF classification (kappa = 0.250-0.478), which showed poor reliability. CONCLUSION: Inter- and intra-observer agreement of the Mason and Morey classifications showed overall satisfactory reliability when compared to the AO/ASIF system. The Mason classification is the most reliable system.