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

BackgroundComplex 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.MethodsForty-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.Results3D CT improved the average ‘inter’-observer reliability of the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification (κ2D = 0.536, 95% confidence interval (CI): 0.481–0.591 vs. κ3D = 0.545, 95% CI: 0.478–0.612), the Hohl and Moore classification (κ2D = 0.668, 95% CI: 0.605–0.732 vs. κ3D = 0.746, 95% CI: 0.605–0.732) and of the Schatzker classification (κ2D = 0.545, 95% CI: 0.494–0.596 vs. κ3D = 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 κ2D = 0.700, interquartile range (IQR): 0.551–0.820 vs. average κ3D = 0.774, IQR: 0.692–0.847); lateral condylar impaction (average, κ2D = IQR: 0.675–0.901 to 1.000 vs. average, κ3D = 0.785, IQR 0.737–0.807); medial condylar impaction (average κ2D = 0.631, IQR: 0.537–0.670 vs. κ3D = 0.719, IQR: 0.679–0.895); tibial spine involvement average (κ2D = 0.621, IQR 0.545–0.678 vs. average κ3D = 0.705, IQR: 0.652–0.794); separation of tibial tubercle necessitating fixation (average κ2D = 0.332, IQR: 0.080–0.574 vs. average κ3D = 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 (κ2D = 0.488 vs. κ3D = 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; κ2D = 0.398, 95% CI: 0.273–0.523 to κ3D = 0.418, 95% CI: 0.262–0.574) and recognition of impaction of the lateral condyle (κ2D = 0.614, 95% CI: 0.467–0.760 to κ3D = 0.693, 95% CI: 0.538–0.849).ConclusionsThe added value of 3D CT after 2D CT is limited and does not significantly improve reliability of characterisation and classification of tibial plateau fractures.