Threaded Needle Fixation

There are few reports on the treatment of intertrochanteric fractures with multi-needle internal fixation. In the past 10 years, multi-needle internal fixation in foreign countries has been mainly used for femoral neck fractures. Only Ender needles for intertrochanteric fractures have been used. Outside the Ender needle, there are mainly four internal fixations by a rectangular needle, three screw internal fixations and a double-needle crane internal fixation. Den-Harton's experiment emphasizes the center position of the femoral neck and head for a single needle such as a compression screw to maintain stress balance during loading, while multi-needle fixation is easier to overcome the balance of the fixation at the center of the neck. used the Singh index test to save the corpse femur, made Evans III a type intertrochanteric fracture, fixed by 4 moments of the Sterling needle, Knowles 4 needles, 140° steel plate and goose nail (nail plate) Test the load bearing and fatigue test on the mechanical test machine. As a result, the bearing capacity, tensile strength and fatigue resistance of the four-dimensional Needle were the best. Followed by the Knowles 4 needles, both superior to the angled steel plate and single nail-plate. Observation of the upper femur bone section showed. In 4 cases of the sigma-like needle, the trabecular bone of the femoral neck near the femoral moment is severely compressed compared with the lateral femoral cortex, suggesting that the femoral head and the internal fixation needle move simultaneously in the neck at the time of hip load, and the femoral moment is dense. The fulcrum is formed at the beam, the pin load arm is shortened, and the bearing capacity is strong. The horn-shaped plate and the goose nail are severely damaged by the trabecular bone at the lateral femoral cortex, indicating that the force point is outside and the load-bearing arm is long. Therefore, although the nail-plate type internal fixation structure itself has more needles Strong, but its biomechanical load performance is not good, the internal fixation nail together with the femoral head and neck, repeated load activity, the force point on the outer cortical corner of the inner stem of the internal fixation, prone to fatigue fracture. The lower two needles of the four teeth of the Sterling needle are moved along the upper trabecular bone of the femur, close to the femoral moment. When the hip is loaded, the lower needle can be the fulcrum of the femoral moment, which shortens the load arm. The Knowles needle inserted parallel to the long axis of the femoral neck is also 4 pieces. Because it is not close to the femoral moment, it can not form a short force arm, and its fulcrum is at the lateral cortex of the femur, so the biomechanical performance is worse than that of the Needles. Compared with the single nails, the internal fixation of the four-pointed Sterling needle has three characteristics: 1 through the femoral lateral cortical bone, the femoral moment and the solid part of the upper end of the femur at the pressure bone of the head, forming a Stable fixed system. 2 The lower needle is nearly parallel to the hip negative gravity line. The normal hip joint negative gravity line projection is 25° to the femoral shaft axis, and the lower needle is about 30° to the femoral shaft axis. When the weight is loaded, the shearing force of the fracture end is small, and the axial force is large, which is beneficial to the insertion of the fracture end, and enhances the stability and promotes the fracture healing. The 3 needles cross each other in the femoral head, increasing the anti-rotation ability, strengthening the stability, 3 screws, and highly inclined fixed intertrochanteric fractures. The same biomechanical characteristics are also observed. 4 needles increase the insurance factor. . If one needle is withdrawn, the other 3 needles will retain their biomechanical characteristics. Dai Kejun et al reported 1978 screw needle internal fixation. Threaded needle manufacturing method: The needle body of a 4mm diameter flat-head stainless steel squid needle is machined into a thread with m4×0.7 round dies, and three stainless steel sleeves with an inner diameter of 4.2 cm and a length of 5 to 7 cm and a metal grid 2 are prepared. Piece. Treatment of diseases: fractures Indication 1. For humeral intertrochanteric fractures, according to Evans classification, this procedure is applicable to type II, type IIIa, type IIIb, and type IV. 2. For type I fractures, although traction therapy generally does not occur in hip varus, there are still some occurrences. Therefore, in order to reduce the bedridden complications of patients and prevent hip varus, this surgery can also be used. Contraindications In the case of retrograde intertrochanteric fracture, the fracture line is obliquely descended from the small trochanter to the lateral femoral cortex. Because the fracture line is consistent with the direction of the pin, it is difficult to fix, so it is a contraindication for this method. As for indications and contraindications for general conditions, this procedure can be applied to most elderly patients with intertrochanteric fractures. There are severe heart, lung, liver and kidney dysfunction, which is a contraindication for surgery. Because the operation is performed under local anesthesia, there is no need for surgical incision, and there is very little blood loss. Therefore, those with mild or moderate heart, lung, liver and kidney dysfunction can generally be tolerated. Preoperative preparation 1. Whole body preparation, blood, heart, lung, liver and kidney function tests after admission, high blood pressure and diabetes cases can be controlled after several days of medication. 2. Local preparation, after the admission, the affected limbs were treated with tibial tuberosity or skin traction, and the affected limbs were kept in the middle rotation position and slightly outside the booth. After the whole body examination was completed, the operation was performed within 3 to 7 days after the injury. 3. 1 day before surgery, routine skin preparation. Surgical procedure 1. Reset: It is best to have a C-arm TV X-ray machine to perform resetting under fluoroscopy. First traction, after recovery under fluoroscopy, observe the normal neck angle, after the fracture line is completely reset, the lower extremity is rotated to the largest trochanter, the outer edge of the tibia is upward, the internal rotation of the foot is about 40°50°, the femur The anteversion angle is nearly disappearing and the limb is fixed. 2. Place a metal mesh on the front and the outside of the hip joint and place the hip side of the hip (or X-ray TV). If the reset is not satisfactory, you should make another adjustment. After the reset is satisfactory, select the best pin position on the X-ray film. The first needle on the anterior slice can be placed on the lateral femoral cortex at 12~14cm below the apex of the femur, so that it passes close to the medial cortex of the femur near the small trochanter and ends at 0.5cm below the cartilage of the femoral head. . On the lateral radiograph, it is at the center of the femoral shaft and the femoral head. Mark each of the above points on the skin of the anterior and posterior femoral sinus, remove the mesh, connect the lateral cortex of the femoral condyle through the proximal medial cortex to the tip of the femoral head and draw a straight line. 1-pin design line. After disinfecting the towel, poke a small hole in the skin of the needle. The sleeve is placed on the front of the threaded needle to expose only the tip of the needle. Puncture through the puncture hole to the needle insertion point of the femoral cortex. Squeeze the needle tail in a vertical position, make the needle tip into the cortical bone a little, in order to prevent the sliding displacement, install the hand drill, tilt the needle while drilling, and drill the percutaneous cortex, the small trochanter should be aligned in the positive position. Medial cortex. Lateral position on the centerline of the femoral shaft and head, continue to drill in. When the needle passes near the medial cortex of the femur of the small trochanter, the resistance can be increased. After that, it is measured in vitro with an isometric threaded needle, estimated to be subchondral. Stop at 0.5cm. After taking the positive side piece and confirming that the needle position is satisfactory, the second and third needles are drilled in the same way. The needle is inserted from the first needle up to about 2 cm per needle, and after the needle position is satisfactory, the sleeve is withdrawn. Press down the soft tissue around the needle, bite off the exposed part of the needle, poke the deep fascia and skin with a vascular clamp or towel pliers, cover the needle tail, and cover the sterile dressing.

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