A finite element analysis of fractures of extended tibial plateau

Objective To analyze the stress distributions under static loading and impact simulation in the process of tibial plateau fracture using finite element analysis, providing evidence for individualized diagnosis and treatment of tibial plateau fracture. Methods A healthy male volunteer was recruited. A 3D finite element model of a whole knee joint with ligaments, menisci and articular surfaces was generated using CT, MRI and 3D finite element software. The knee joint model was given the nature and parameters after reconstruction. According to the features of tibial plateau fracture, different operating conditions were designed. The stress distributions under static loading and impact simulation in the process of tibial plateau fracture were characterized by finite element analysis. Results Under static loads on the lateral condyle of the tibia, the stress was mainly concentrated on the front edge of the tibial plateau, especially the lateral stress. The stress on the medial condyle of the tibia was significantly increased, and the medial stress extended downwards to the tibial shaft. When the vertical stress moved towards outside, it extended from both sides of the internal and external condyles downwards to the tibia, and the value of lateral platform stress was slightly larger than that on the inside. In collisions, the stresses distributed on the neutral position were the same with the static loads. The stress on the medial condyle of the tibia was significantly increased, extending downwards the tibial shaft when it fell to the inside slope. When it fell to the outside slope, the stress on the tibial plateau was mainly distributed on most of the front edges of lateral and medial platforms, and the stress distributed on the fibula increased obviously. Conclusions The medial tibial plateau plays a major role in bearing stress loads. The stress is more concentrated on the lateral platform but distributed on a larger area of the medial platform, extending downwards the metaphysis. Therefore, small split fractures are likely to occur on the outer edge of the platform while fractures of a large fragment are likely to occur on the medial platform, even involving the metaphysis. Key words: Knee joint; Tibial fractures; Finite element analysis; Static load; Collision