Single-position 5f milk m Guangdong Zhuhou Street alElecfro coffee brewing ishing* between the two to achieve good results through biomechanical research and clinical application, confirmed that Richard nail has static pressure and dynamic compression. Wang Fuquan et al reported that the nail has a flexural strength of 280 kg, which can transmit the various stresses of the femoral head to the upper and middle part of the femur. The solid cortical part can withstand the load of the human body, and the thick screw can be placed along the sleeve. The tube slides, and it is not easy to cause the nail tip to cut the bone to pass through the femoral head. When the weight is loaded, the proximal femur inner cortex is under compression, and the lateral cortical is subjected to tensile stress. Richard nails the lateral cortex by the telescopic plate, which mainly shares the tensile stress, so the nail has a tension band effect. Richard's strong internal fixation and dynamic compression function, while the fracture end absorbs and compresses, the nail can still exert pressure and firm internal fixation, which can allow patients to perform early functional exercise and lower ground activities. However, the nail is disadvantageous in that it cannot effectively prevent the rotational displacement of the fracture end, that is, the torsion resistance is poor. Fan Weimin 6 through experiments proved that the Richard nail anti-rotation strength is 3. *m, when the rotating torque reaches 3kg * m, the pin in the Richad nail sleeve slips off. For patients with severe comminuted femoral trochanteric fractures, due to Richard's poor anti-rotation effect, affecting the fracture fixation strength, it is not suitable for the use of Richad nails, and other internal fixations should be used.

2.3Richard nail plus cancellous bone screw internal fixation advantages In order to strengthen Richard's anti-torsion force, we took Richard nail and cancellous bone screw for internal fixation, which changed the proximal end of the fracture and only became a "point" fixed and became "face". The fixing is to avoid stress concentration, thereby greatly enhancing the anti-rotation ability and internal fixation. It has the following advantages: (1) Strengthening the rigid compression and dynamic compression of Richard nails, effectively controlling the proximal end of the intertrochanteric fracture, and strengthening the anti-torsion ability; (2) Continuous compression of the fracture block The end makes it close contact, strengthens the internal fixation, and can be applied to severely comminuted fractures between the femoral trochanter; (3) It can be used for early functional exercise and weight-bearing in the lower ground to reduce complications. In this group of patients, the patient was allowed to perform functional exercise after the operation. After 2 weeks, the patient began to walk under the abduction and did not carry heavy weight, and then gradually loaded according to the fracture healing condition until the weight was fully loaded. For patients with severe comminuted fractures, the weight-bearing time of the lower ground can be prolonged. No cases of disability and internal fixation failure due to long-term bed-ridden complications have achieved satisfactory results.

Points to note: (1) Most patients with intertrochanteric fractures are elderly, often complicated with serious medical conditions. The systemic condition should be checked before surgery, and the perioperative medical treatment should be emphasized, and surgery should be performed within 1 week; (2) Intraoperative fracture block should be dissected and reconstructed as much as possible. The fracture side of the fracture should be fixed and the bone graft should be performed as much as possible. The position of the compression screw in the femoral head should not be located at the upper limit of the femoral head in the fluoroscopic position of the C-arm X-ray machine. The lateral position should be in the center of the femoral head. If there is no C-arm X-ray machine, it is best to expose the front lower edge of the femoral head during surgery to grasp the direction and position of the nail under direct vision. Select a suitable angle sleeve steel plate, the angle is equal to or greater than the healthy side neck dry angle.

The length of the thick screw should be suitable, and the nail tip can reach 1.0cm below the head of the femur. Otherwise, the sleeve is prone to be too short, the compression is too long, and the femoral head is easy to wear. (3) After the operation, the hip muscles and quadriceps function can be practiced in the early stage of the bed. The post-operative activities should determine the activity time according to the patient's age, fracture type, and presence or absence of osteoporosis. Generally, about 2 weeks after surgery. Can walk abducted, but for severely comminuted fractures, patients with severe osteoporosis must extend the time to go to the ground.

The Richard nail and cancellous bone screw used in this group are all titanium alloy materials, and the surface of the body is easy to form a dense titanium dioxide film. It has strong corrosion resistance, low density, and the elastic modulus is similar to that of human cortical bone. Good compatibility, no need for secondary surgery to remove nails, reduce trauma and pain, reduce the economic and physical and psychological burden of patients, improve the quality of life, and accept for the majority of patients.

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