RÉSUMÉ
BACKGROUND:There is currently no anatomic locking plate suitable for the anteromedial platform,so the medial locking plate of the tibial plateau is usually placed forward to fix anteromedial compression fractures caused by hyperextension varus injury.Due to the inability of the locking screw to achieve vertical fixation of the fracture line,coupled with the influence of the patellar ligament,the clinical results are still unsatisfactory. OBJECTIVE:To compare the biomechanical performance of a new type of plate with traditional internal fixation methods in treating hyperextension varus tibial plateau fractures through finite element analysis. METHODS:CT data of 20 cases of hyperextension varus tibial plateau fractures were collected,and their morphological characteristics,such as medial posterior tibial slope,the medial articular fracture angle,surface area,and anterior cortical height were measured.A 24-year-old male volunteer with a height of 175 cm and a weight of 65 kg was selected,and his tibial CT data were imported into Mimics 21.0 software to generate a 3D model.Then,internal fixation models were imported into SolidWorks 2017 software.New type of plate,medial locking plate,posterior medial locking plate,and 6.5 mm hollow screws fixed data models were established based on the measured morphological data.Ansys 17.0 software was used to load stress on the four fixation models and compare their biomechanical performance. RESULTS AND CONCLUSION:(1)With the increase of axial load,the peak stresses of different internal fixation models approximately increased proportionally.At 500 N,the peak stress values were as follows:screw group(6.973 7 MPa)<new steel plate group(14.733 MPa)<medial locking plate group(16.445 MPa)<posterior medial locking plate group(25.199 MPa).(2)The peak stresses of the fracture block were as follows:at 500 N,screw group(3.657 9 MPa)<new steel plate group(4.510 8 MPa)<medial locking plate group(5.225 9 MPa)<posterior medial locking plate group(6.181 2 MPa).(3)With the increase of axial load,the displacement of the fracture block and internal fixation approximately increased proportionally,and the displacement distribution characteristics showed no significant changes.At 500 N,the steel plate displacement values were as follows:new steel plate group(1.030 7 mm)<medial locking plate group(1.503 mm)<screw group(2.096 5 mm)<posterior medial locking plate group(2.258 2 mm).At 500 N,the fracture block displacement values were as follows:new steel plate group(0.212 8 mm)<medial locking plate group(0.311 54 mm)<screw group(0.427 79 mm)<posterior medial locking plate group(0.454 98 mm).(4)It is concluded that in the treatment of hyperextension varus tibial plateau fractures,the stability and mechanics of the new steel plate are superior to traditional internal fixation methods.