Importance of the posterior plate in three-column tibial plateau fractures: Finite element analysis and clinical validation

Abstract

Background The medial and lateral dual-plates fixation is considered as the standard method for most bicondylar tibial plateau fractures. Nevertheless, with the concept of the three-column developed, the importance of the anatomical reduction of the posterior column has been stressed. By recent clinical studies, it was advocated the fixation should direct at each sub-column, but it has not been proven by the experimental validation so far. Methods Finite element analysis and clinical case series study were contained in this paper. In finite element (FE) study, three experimental models were established: longitudinal triple-plates group (LTPG), oblique triple-plates group (OTPG) and dual-plates group (DPG). Three loading scenarios of a 60kg adult in the physiological walking gait were performed. The distribution of the deformation and the equivalent von Mises stress (VMS) in each structure was calculated for comparison. The comparative measurements including the maximum posterior column collapse (MPCC), the maximum total displacement of the model (MTD), the maximum VMS of cortical posterior column (MPC-VMS) and the maximum VMS located on each group of plates and screws (MPS-VMS).The clinical study evaluated the indicators between the groups with or without the posterior plate, including operation time, blood loss volume, full-weight bearing period, Hospital for Special Surgery Knee Scoring system (HSS), Rasmussen score and common postoperative complications. Results In the FE analysis, under all loading conditions, the MPCC was found significant less in LTPG and OTPG compared with DPG (reduced at least 38%), and the difference between the LTPG and OTPG was not significant. The largest MPC-VMS was found in DPG (reduced by 14% in LTPG and 2% in OTPG). The largest MPS-VMS was found in LTPG, followed by OTPG, and the smallest group was DPG, 40% increment was found in LTPG and 19% in OTPG at most. The MTD was found significant less in LTPG and OTPG (reduced by 35% and 42% at most in LTPG and OTPG). In the clinical study, 35 cases were included (14 cases in triple-plates group and 21 cases in dual-plates group). Among them, the operation time was 115.6 minutes and 100.5 minutes in the triple-plates group and the dual-plates (P < 0.05), the blood loss volume was 287.0 ml and 206.6 ml (P < 0.05), the full-weight bearing period was 14.5 weeks and 16.2 weeks (P < 0.05). At the final follow-up, the HSS score was 85.0 in the triple-plates group and 77.5 in the dual-plates (P < 0.05), the Rasmussen score was 24.1 and 21.6 (P < 0.05), there was one case superficial incision infection in triple-plates group. Conclusion The application of the supplementary posterior plate was beneficial to optimize the biomechanical stability and functional outcome in the three-column tibial plateau fractures.