Currently, the surgical methods for intertrochanteric fractures can be divided into extramedullary and intramedullary fixation, the former being represented by the powered hip screw (DHS) and the latter by the proximal femoral intramedullary nail (PFN), the DHS being more suitable for stable fractures and the PFN for unstable fractures with severe comminution. Because the biomechanical properties of the PFN system conform to the biological negative gravity line, it can bear most of the load passing through the proximal femur, especially the medial side, and the compressive stress in the femoral talar area is reduced to almost zero, and the force arm is shifted inward, significantly reducing the tensile and compressive stresses at the nail rod union, with little stress masking, which helps fracture healing. For patients with osteoporosis. The choice of an intramedullary fixation device is superior to the choice of a standard sliding-slot nail system. PFNA is widely indicated for all types of intertrochanteric fractures (AO subtypes A1, A2, A3) and high-grade subtrochanteric fractures, but not for fractures of the femoral head and neck. PFNA is a new and improved PFN system, which on one hand inherits the advantages of the original PFN with the same biomechanical characteristics, and on the other hand has innovations in the specific design, making the fixation more effective and easier to operate. (1) In contrast to PFN, PFNA replaces the traditional 2-screw fixation with a helical blade locking technique. The unlocked helical blade enters the bone by rotation when it is tapped in and acts as a filler for the bone, and the blade has a wide surface area and a gradually increasing core diameter (4.5-9 mm) to ensure maximum bone filling and ideal anchoring force. This is also true in patients with severe osteoporosis. When the blade is inserted and locked, the blade cannot rotate and is anchored tightly to the bone, making it difficult to loosen and withdraw. It is also suitable for fractures at the lateral femoral spiral blade penetration, which is more conducive to early weight bearing. (2) Secondly, PFNA requires only one spiral blade, which is suitable for patients with thin femoral neck and easy to operate. (3) PFNA has the following improvements in the main nail: ① The main nail is designed to be hollow, only a small incision is needed to allow the guide pin to enter the medullary cavity, and then the subsequent operation can be completed smoothly to place the main nail, which has a 6° external deviation angle to facilitate insertion from the tip of the greater trochanter into the medullary cavity; the main nail of PFN is solid, and the positioning of the nail point needs to be accurate, if the nail point is poorly positioned, the main nail often deviates from the center of the medullary cavity or the fracture is displaced, making insertion difficult, which can lead to the operation time. If the nail is not positioned correctly, the nail may be displaced from the center of the medullary cavity or the fracture may be displaced, resulting in difficult insertion, which may lead to prolonged operation time and increased trauma. Therefore, PFNA is simpler and less traumatic, which is in line with the principle of minimally invasive surgery. ②There is only one locking hole at the distal end of the PFN, and static or dynamic locking can be chosen. In the case of trans-rotor fracture, as the use of a vertically driven locking nail may damage the proximal locking, an obliquely driven locking nail must be used, and in the case of high subrotor fracture, a vertically driven dynamic locking nail can be chosen. ③ The main nail has the longest possible tip and groove design, which makes insertion easier and avoids local stress concentration, reducing the incidence of broken nails and re-fractures at the tail of the nail.