Finite element analysis of combined fixation of Pauwels type Ⅲ femoral neck fracture with posteromedial bone defects of varying degrees using a medial support plate

Yusufu·Reheman; Mutalipu·Silamujiang; Alimujiang·Yusufu; Zhang Ziyi; Ran Jian

doi:10.12307/2026.733

Abstract：BACKGROUND:Pauwels type Ⅲ femoral neck fractures are often accompanied by different degrees of bone defect.The degree of bone defect and stability of internal fixation are key factors affecting fracture healing. OBJECTIVE:To simulate and compare the stability of different degrees of bone defects fixed by finite element analysis to provide experimental basis for actual clinical surgery. METHODS:Mimics 21.0,Geomagic and Solidworks software were used to construct a model of femoral neck fracture with Pauwels angle of 70° and four posteromedial bone defects of different degrees.Three internal fixation methods of hollow nail combined with medial support plate,femoral neck dynamic cross-fixing system combined with medial support plate,and femoral neck dynamic cross-fixing system alone were simulated to form 12 groups of fracture bone defect internal fixation model groups.The stress and displacement changes of femur,internal fixation,and femoral head of 12 groups of models were analyzed under the load of 3 ploid mass of 2 100 N. RESULTS AND CONCLUSION:(1)In all degrees of bone defects,the displacement and stress of the hollow nail combined with the medial steel plate were smaller than those of femoral neck dynamic cross-fixing system combined with the medial steel plate and femoral neck dynamic cross-fixing system fixation alone,regardless of whether the femur was fixed as a whole or internally.(2)With the increase of the volume of the posterior medial femoral bone defect,the displacement of the femur and internal fixation showed an increasing trend.(3)It is concluded that compared with femoral neck dynamic cross-fixing system combined with steel plate fixation,hollow nail combined steel plate fixation has more advantages in biomechanics,which is manifested as smaller displacement peak,more uniform stress distribution and lower stress concentration risk.Structural support reconstruction of the bone defect is extremely important for the treatment of femoral neck fractures with moderate to large bone defects.