The main factors that cause the tendency to redisplace the fracture are:
1. Limb gravity: The weight of the injured limb is one of the important factors for fracture re-displacement. After the limb is fractured. The distance between the center of gravity and the fracture line can determine the size of the redisplacement tendency. The closer the center of gravity is to the fracture line, the smaller the tendency of re-displacement caused by eye gravity; the farther the center of gravity is from the fracture line, the greater the tendency of re-displacement. The weight of the limb cannot be changed, but its center of gravity moves with the extension and flexion of the limb.
It happens that the local external fixation of the small splint does not exceed the upper and lower joints of the fracture, and during flexion, the center of gravity is kept at a small distance from the fracture line. At the same time, this kind of external fixation device is very light in weight and hardly increases the weight of the limb. Both the upper and lower joints are fixed. The gravity of the limb below the joint at the distal end of the fracture is absorbed by the active joint, and the displacement of the fracture end is also greatly affected. reduce. Therefore, this external fixation device is currently the most ideal external fixation.
2. Muscle pulling force: The muscle contraction activity has a direct impact on the fracture re-displacement. At the same time, the fracture end can be maintained in the position after restoration through the coordinated movement of the muscle, which can be formed during the muscle relaxation and contraction activities. Longitudinal extrusion of the fractured ends, intercalation with each other. Therefore, using a small splint and a pressure pad to prevent the fracture from re-displacement by leveraging, relatively stabilizing the position of the fracture end and increasing mutual entrapment can not only control the brace movement (rotation, angulation, separation) that is not conducive to fracture healing, but also Preservation of movement favorable for fracture healing (opposite compression). Why the small splint external fixation device can receive a good fixation effect can be explained from the following aspects:
1. The upper and lower joints of the fractured part are not fixed. Most of the muscles of the limbs play the role of maintaining and fixing the muscles through 1-2 joints. Under normal circumstances, the upper and lower joints of the fracture cannot be fixed, but if necessary, super-joint fixation can be performed to control certain factors that can cause fracture displacement. Joint activity in one direction increases the relative stability of the fracture end and is conducive to fracture healing.
2. Control the rotation. If the forearm is fractured, due to the existence of the inherent rotator muscle group, it must be fixed in a neutral position with a sub-bone pad and a dorsal volar splint to control the rotational activity of the forearm to prevent rotational displacement.
3, to prevent the angle. The angulation of the fracture is caused by an imbalance of muscle tension on both sides. During fixation, the three-point extrusion of the pressure pad and the pressure pad placed on the splint is applied according to the direction of muscle tension to overcome the phenomenon of unbalanced muscle tension on both sides, which can prevent or correct angular deformity.
4. Longitudinal extrusion is tightly embedded. The external fixation device not only overcomes the re-displacement of the fracture, but also uses the internal power generated by muscle contraction to squeeze the longitudinal axis of the backbone, so that those with mild separation can insert the fractured ends into each other. , to increase the contact surface of the broken end, which is conducive to fracture healing.
5, to fully mobilize the patient's subjective initiative. First, explain the role of the local external fixation device to the patient, and under the guidance of medical staff, perform functional exercises that are conducive to fracture healing, which mobilizes the coordinated activities of the muscles and has a positive effect on promoting fracture healing.