To compare the biomechanical stability of AO2.1 type intertrochanteric fractures treated with dynamic hip screw (DHS) and proximal femoral nail antirotation (PFNA) internal fixation.

Using the finite element analysis method, the normal femur, DHS fixed fracture model and PFNA fixed fracture model were established by Mimics software and Geomagic software respectively. The finite element analysis software was used to simulate the femoral weight (the maximum peak of the femur when standing on one leg). Femoral stress analysis, internal and external femoral stress, femoral head displacement and internal fixation stress and displacement were used to compare the effects of two internal fixation methods on femoral biomechanics.

The internal and external femoral stress of PFNA group was less than that of DHS group, and the internal fixation itself stress and displacement of PFNA group was also smaller than the DHS group.

In the treatment of AO2.1 femoral intertrochanteric fractures, the values of the internal and external femoral stress, femoral head displacement, internal fixation stress and displacement of PFNA are smaller than those of DHS group, and are closer to the normal femur; PFNA may have biomechanical advantages over DHS in the treatment of this type of fracture.