Injury pattern simulation and mapping of complex tibial plateau fractures that involve the posterior plateau with three-dimensional computed tomography

BACKGROUND: Tibial plateau fractures involving the posterior plateau (TPFIPs) are complex intra-articular fractures that are difficult to stabilize. Understanding the characteristics of these fractures together with the injury pattern is beneficial for surgeons to choose an optimal treatment strategy. However, the complicated morphology and injury patterns of TPFIPs are poorly characterized. The purpose of this retrospective study was to investigate the injury patterns and fracture characteristics of complex TPFs by applying three-dimensional (3D) simulation and fracture mapping methods. METHODS: In total, 171 TPFIPs were retrospectively reviewed, and the injury pattern was simulated and analyzed by applying a 3D method with Mimics software, which allowed matching of the fractured articular surfaces of the tibial plateau to the femoral condyle surface. The major articular fracture lines were mapped and then superimposed on a template. The tibial motion angle after fracture injury pattern simulation and the major fracture line angle were quantitatively analyzed, while the injury patterns and fracture characteristics were qualitatively analyzed. RESULTS: Four main injury patterns with distinctive fracture characteristics were observed in this study. In total, 72 TPFs exhibited extension as the pattern of injury with a split posterolateral fragment, and 61 fractures exhibited the flexion-internal rotation injury pattern; compression was the main feature of posterolateral fractures. Furthermore, 21 fractures exhibited the flexion-external rotation injury pattern, with a small posteromedial fragment, and 17 fractures exhibited the flexion-neutral injury pattern, with both parts of the posterior plateau fracture and anterior dislocation being observable. The major articular fracture line angles were significantly different between the four main injury patterns (85.92°, 46.79°, 148.26°, and 16.21°, median values, P<0.05). Two injury patterns, namely, flexion-internal rotation and flexion-external rotation, exhibited rotation in the axial plane (24.13°±8.33°, −15.13°±5.14°, P<0.05). CONCLUSIONS: In this study, a method involving a simulated injury pattern was developed and combined with evaluations of fracture characteristics, including two-dimensional (2D) and 3D analyses, to comprehensively describe both the morphologies and injury patterns of TPFIPs.