Biomechanical analysis of anatomical intramedullary nails and proximal femoral anti-rotation-II intramedullary nails for the treatment of unstable intertrochanteric fractures (AO type 31-A2.2) in older patients

In AO type 31-A2.2 unstable intertrochanteric fractures, the biomechanical properties of the ZNN group were superior to those of the PFNA-II group in terms of axial stiffness and failure load. In the cyclic loading test, the axial displacement of the femoral head was similar in both groups. The finite element analysis showed a more favorable mechanical distribution for the ZNN group. The ZNN implant demonstrated favorable biomechanical characteristics under the specific experimental conditions tested in this study.