Comparative Analysis of Mechanism-Associated 3-Dimensional Tibial Plateau Fracture Patterns

Background: The association between tibial plateau fracture morphology and injury force mechanism has not been well described. The aim of this study was to characterize 3-dimensional fracture patterns associated with hypothesized injury force mechanisms. Methods: Tibial plateau fractures treated in a large trauma center were retrospectively reviewed. Three experienced surgeons divided fractures independently into 6 groups associated with injury force mechanisms proposed from an analysis of computed tomographic (CT) imaging: flexion varus, extension varus, hyperextension varus, flexion valgus, extension valgus, and hyperextension valgus. The fracture lines and comminution zones of each fracture were graphically superimposed onto a 3-dimensional template of the proximal part of the tibia. Fracture characteristics were then summarized on the basis of the fracture maps. The association between injury force mechanism and ligament avulsions was calculated. Results: In total, 353 tibial plateau fractures were included. The flexion varus type pattern was seen in 67 fractures characterized by a primary fracture apex located posteromedially and was frequently associated with concomitant anterior cruciate ligament (ACL) avulsion (44.8%). The extension varus pattern was noted in 60 fractures with a characteristic medial fragment apex at the posteromedial crest or multiple apices symmetrically around the crest and was commonly completely articular in nature (65%). The hyperextension varus pattern was seen in 47 fractures as noted by anteromedial articular impaction, 51% with a fibular avulsion and 60% with posterior tension failure fragments. The flexion valgus pattern was observed in 51 fractures characterized by articular depression posterolaterally, often (58.9%) with severe comminution of the posterolateral cortical rim. The extension valgus patterns in 116 fractures only involved the lateral plateau, with central articular depression and/or a pure split. The hyperextension valgus pattern occurred in 12 fractures denoted by anterolateral articular depression. A moderate positive association was found between flexion varus fractures and ACL avulsions and between hyperextension varus fractures and fibular avulsions. Conclusions: Tibial plateau fractures demonstrate distinct, mechanism-associated 3-dimensional pattern characteristics. Further research is needed to validate the classification reliability among other surgeons and to determine the potential value in the diagnosis and formulation of surgical protocols.