plate screw fixation

This kind of internal fixation is mostly used for long bone fractures, which is relatively reliable and has many clinical applications. However, the shortcomings are long incision, soft tissue separation and periosteal dissection. The blood flow at the fracture end is heavier and the healing is slower. Treatment of diseases: humeral shaft fractures Indication 1. The long bone or long oblique fold of the long bone of the extremities, manual reduction, external fixation failure or other reasons can not be manually reset, external fixation. 2. Multiple fractures of the whole body or multiple fractures of the bone, all of which are difficult to be treated by manual reduction or external fixation. It may be considered to be difficult to maintain the anterior fracture of 1 or 2, or to fix the fracture of the external fixation. Surgery. 3. When the fracture deformity is healed or not healed, it is necessary to perform surgical treatment (such as osteotomy, bone graft, etc.), and it is necessary to use the steel plate for internal fixation at the same time to restore the bone stent. 4. After the bone deformity orthopedic surgery (such as subtrochanteric osteotomy or femoral or humeral humerus), it can be fixed with prefabricated angled steel plates or pressed angled steel plates (such as enamel steel plates). 5. Some long oblique, spiral, butterfly-shaped comminuted fractures can also be fixed with compression screws and balance plates, which can effectively counteract the torsion, scissors and bending stress. 6. The comminuted fracture or defect of the metaphysis is to protect the graft bone and the broken bone piece to prevent compression and fix it with the pillar steel plate, which can play a bridging role to ensure the healing of the bone graft. Preoperative preparation 1. Steel plate requirements: The cross section of the steel plate should be curved, and it can be closely attached to the circular bone surface. The steel plate hole should have inclined depressions, so that the semi-recessed head can be embedded correspondingly to increase the fixing effect. It can reduce the protrusion of the screw head and cause pain. 2. Selection of steel plates: There are many types of steel plates. The type with good fixation effect should be selected according to the fracture site, shape and diameter of the bone. The steel plate is divided into two types: ordinary steel plate and pressure steel plate according to its performance. The latter has round holes (static pressure) and self-pressing steel plate (power pressurization) and a variety of special specifications steel plates. The following commonly used types of steel plates are as follows: Straight long steel plate: mostly used for long bone fractures. The length of the selected steel plate should be 4 to 5 times the diameter of the broken bone. Generally, 8 holes are used for the femur, 6 holes for the tibia, and 4 holes for the tibia. Angled pointed steel plate: mostly used for supracondylar fracture of the femur or intertrochanteric osteotomy. Angled steel plate: for long bone osteotomy. Rotor plate: used for internal fixation after intertrochanteric osteotomy of the femoral neck fracture. Trigeminal plate: for y- or t-shaped fractures of the ankle. Pressurized steel plate: It is thicker than ordinary steel plate. It is equipped with pressurized cortical bone screw. It can be pressurized and firmed by the pressure device or specially designed steel plate (automatic compression plate). 3. Screw selection: same as screw internal fixation. 4. Pressurizer: It consists of a presser hole, a hook and a pressure screw, and is equipped with a movable wrench and a drill guide (drill). Surgical procedure (1) Ordinary steel plate screw internal fixation 1. Placement of the plate: After the reduction of the fracture, according to the size of the plate, the local periosteum is removed, the fracture is placed behind the fracture, the plate is placed on the bone surface, and the fracture end is pressed together, and then the sliding part of the fracture holder is tightened. The fracture and the steel plate can be temporarily fixed together, but care should be taken to expose all the steel plate holes for drilling. 2. Drill and screw in the screw: first drill a hole in each end of the steel plate. The drill bit needs to be drilled vertically in the center of the steel plate hole. After drilling through the cortical bones on both sides, measure the diameter of the bone with a bone hole sounder, and add the thickness of the steel plate. Select the screw with the same length (except the nail tip) according to the length and screw it in the direction of the hole. Then drill the hole in each hole of the steel plate, screw in the screw, and tighten them in sequence. The method of drilling and placing screws is the same as "screw internal fixation". (2) Pressurized pressure plate steel screw internal fixation After the fracture was restored, the compression plate was placed and fixed with the bone holder, a hole with a diameter of 3.2 mm was drilled on the plate hole of the short fracture section about 1.0 cm from the fracture line, and the cortical bones were drilled through both sides. Use a sounder to measure the depth of the hole to select the appropriate length of the screw. Use a tap to tap the pattern of the bone hole and screw in the first cortical bone screw. After resetting and fixing the fracture end and the steel plate again, place the drill guide of the presser and drill a 3.2 mm bone hole. Adjust the presser so that the hook hooks the end hole of the pressure steel plate, and align the hole of the presser with the bone hole, and screw a common screw to fix the pressurizer. While maintaining the anatomical reduction, gently tighten the pressurizer with a cannula wrench to allow the two fold ends to be initially longitudinally pressurized. Then, a 40 mm long 3.2 mm diameter drill bit was drilled through the guide, the bone hole pattern was tapped with a tap, and the second and third cortical bone screws were screwed into the remaining two holes of the pressurized steel plate. Be sure to align the center of the steel plate hole when drilling. Be sure to protect it with tap sleeve when tapping, so as to prevent the tap from being damaged by the card or the surrounding soft tissue. Use a wrench to further tighten the pressurizer so that the fracture ends are tightly connected and the pressure can reach 40 to 50 kg. After pressurization, check whether there is displacement at the fracture end. If there is no displacement, use the same method to screw the 4th and 5th cortical bone screws on the plate with the pressurizer side. Finally, loosen and remove the presser and screw in the 6th short cortical bone to fix the cortical bone on the side to reduce stress and block. For short bevel fractures, the compression screw should be used to bend the fracture line through the plate hole to strengthen the fixation effect. (3) Automatic pressing steel plate screw internal fixation When using an auto-pressurized steel plate, do not use a pressurizer. Since the steel plate holes are designed and manufactured in two semi-cylindrical patterns. The principle is to use the principle of spherical sliding, that is, when the screw is screwed into the inclined cylindrical end, the screw head moves along the inclined bearing plane of the steel plate hole to the horizontal sliding plane, and the fracture end generates the centripetal horizontal movement, thereby generating pressure. effect. After placing the steel plate, drill the hole at the fracture end of the near fold, guided by the neutral guide drill, tap the threaded thread, screw the first cortical bone screw, but do not tighten, accurately reduce the fracture, and insert the hook into the plate hole to the distal end. Pull the steel plate so that the first screw is at the eccentric position of the steel plate hole. Then, at the fracture end of the far-fold segment, the eccentric guided drill (bearing guide drill) is used to guide the eccentric bore. The position of the drill hole should be as close as possible to the distal end of the steel plate hole. Screw the second cortical screw into the same method and tighten it. Tighten the first screw to bring the fracture end closer together and create a pressurizing effect. Then, screw in the remaining screws at the center of the plate hole or slightly eccentrically. (four) bone grafting Fractures more than 3 weeks after injury, especially in areas that are not easy to heal (such as the lower part of the humerus, the upper part of the ulna, the lower part of the humerus), bone transplantation should be performed at the same time as internal fixation to promote healing. complication 1. The reasons for the bending and fracture of the steel plate are mostly due to the fact that the external fixing or external fixing time is too short, and the limited fixing force of the steel plate is excessively dependent on the load or the movement, so that the steel plate is bent or broken. Once it should be re-operated, remove the steel plate and fix it separately. 2. Steel plate can not be taken out: Sometimes it is very difficult to remove the steel plate. The main reason is that the groove of the screw head is damaged, and the rotary chisel cannot function. The cortical bone around one end of the screw should be cut off a little thickness, and the steel plate should be pressed down with a wire cutter to expose a small number of screws. The screw can be screwed out with a wire cutter, then the steel plate is lifted, and the other screws are taken out in the same manner. 3. After the strong internal fixation with the pressure plate, the elastic modulus of the steel plate and the bone are very different, and the weight of the limb is mostly passed through the steel plate without passing through the bone under it, causing the bone to shrink at the fixed part of the steel plate. The junction of bone and atrophic bone is easily broken or re-fracture occurs after the plate is removed. Therefore, after the steel plate is out, it still needs to be properly protected for 3 to 6 months to avoid breaking. The fracture often occurs at the most distal nail hole of the plate. To prevent its occurrence, the most distal screw of the plate can pass through only one side of the cortical bone. In this way, the load-bearing stress of the limb can be avoided from being concentrated on the steel plate end, but the bone gradually transitions to the steel plate to buffer the sudden change of the elastic modulus between the bone under the steel plate and the normal bone.