In this study, finite element analysis method was used to compare the biomechanical characteristics of femoral neck system (FNS) and three hollow screws combined with medial plate fixation of Pauwels type Ⅲfemoral neck fracture, so as to provide reference for the selection of clinical surgical options.

The CT scanning data of the healthy femur of a hospitalized patient with Pauwels III femoral neck fracture (male, 35 years old) were collected, and the CT data of the femur were used to establish the three-dimensional model of the femur by digital medical software. The femoral neck was simplified and segmented according to the angle of 60° fracture line, and the Pauwels III femoral neck fracture was simulated. In Solidworks 2017 software, the simulated internal fixation model was placed in the femoral model according to the corresponding clinical internal fixation size and surgical scheme, and it was divided into two models, FNS placement and three hollow nails plus medial plate placement. Finally, ANSYS software was used meshing, material assignment and data calculation. What was the difference in biomechanical stability between FNS and three hollow nails plus medial plate fixation.

The peak stress of femoral head were, a: 126.74 Mpa, b: 180.11 Mpa. The peak stress of internal fixation were, a: 143.17 MPa, b: 214.68 MPa. The peak displacement of femoral head were, a: 10.726 mm, b: 11.278 mm. The peak displacement of internal fixation were, a: 10.164 mm, b: 11.004 mm.

FNS for the fixation of the fracture end is better than that of the hollow nail and the medial plate, and the femoral neck system has the advantages of small incision and short timeconsuming in the operation process, which is a preferred surgical fixation method for femoral neck fractures.