Two-dimensional and three-dimensional computed tomography for the classification and characterisation of tibial plateau fractures

Background: Complex tibial plateau fractures can be difficult to characterise on plain radiographs and two-dimensional computed tomography (2D CT). The present study evaluated whether three-dimensional computed tomography (3D CT) reconstructions can improve the reliability of complex tibial plateau fracture characterisation and classification. Methods: Forty-five consecutive intra-articular fractures of the tibial plateau were evaluated by six independent observers for classification according to standard systems and for the presence of six characteristics: (1) posteromedial shear fracture; (2) coronal plane fracture; (3) lateral condylar impaction; (4) medial condylar impaction; (5) tibial spine involvement; and (6) separation of tibial tubercle necessitating fixation. Two rounds of characterisation and classification were performed: the first classification after a combination of plain radiographs and 2D CT and the second one after 3D CT information were added. Results: 3D CT improved the average 'inter'-observer reliability of the Arbeitsgemeinschaft fur Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification (kappa 2D = 0.536, 95% confidence interval (CI): 0.481-0.591 vs. kappa 3D = 0.545, 95% CI: 0.478-0.612), the Hohl and Moore classification (kappa 2D = 0.668, 95% CI: 0.605-0.732 vs. kappa 3D = 0.746, 95% CI: 0.605-0.732) and of the Schatzker classification (kappa 2D = 0.545, 95% CI: 0.494-0.596 vs. kappa 3D = 0.596, 95% CI: 0.538-0.654). 'Intra'-observer reliability also improved non-significantly for all systems after the addition of 3D CT for individual observers. 3D CT did improve the 'intra'-observer reliability for the identification of the following fracture characteristics: coronal plane fracture (average kappa 2D = 0.700, interquartile range (IQR): 0.551-0.820 vs. average kappa 3D = 0.774, IQR: 0.692-0.847); lateral condylar impaction (average, kappa 2D = IQR: 0.675-0.901 to 1.000 vs. average, kappa 3D = 0.785, IQR 0.737-0.807); medial condylar impaction (average kappa 2D = 0.631, IQR: 0.537-0.670 vs. kappa 3D = 0.719, IQR: 0.679-0.895); tibial spine involvement average (kappa 2D = 0.621, IQR 0.545-0.678 vs. average kappa 3D = 0.705, IQR: 0.652-0.794); separation of tibial tubercle necessitating fixation (average kappa 2D = 0.332, IQR: 0.080-0.574 vs. average kappa 3D = 0.441, IQR: 0.325-0.681). The only improvement that was found to be statistically significant was for recognition of medial condylar impaction as the IQR did not overlap. 3D CT had limited influence on average 'inter'-observer reliability for the recognition of all specific fracture characteristics (kappa 2D = 0.488 vs. kappa 3D = 0.485, both moderate agreement for all fracture characteristics) but showed a non-significant improvement of the recognition of coronal plane fractures (fair to moderate; kappa 2D = 0.398, 95% CI: 0.273-0.523 to kappa 3D = 0.418, 95% CI: 0.262-0.574) and recognition of impaction of the lateral condyle (kappa 2D = 0.614, 95% CI: 0.467-0.760 to kappa 3D = 0.693, 95% CI: 0.538-0.849). Conclusions: The added value of 3D CT after 2D CT is limited and does not significantly improve reliability of characterisation and classification of tibial plateau fractures. (C) 2011 Elsevier Ltd. All rights reserved.