1. Continuous bone traction should be performed for about 1 week before surgery for old dislocation.

2. Selection of exposure approach: The exposure approach for hip dislocation can be the anterolateral exposure approach or the posterior exposure approach. The former is in the supine position, and manual reduction is more convenient, but the dislocated femoral head is located behind the ilium and is relatively deep, making separation difficult. Posterior exposure is generally performed in the prone position, and exposure of the femoral head, sciatic nerve, and acetabulum is straightforward and easy; however, manual reduction is inconvenient. This difficulty can be overcome by changing the body position to a lateral or prone position. Therefore, anterolateral exposure may be considered for anterior dislocations and some fresh posterior dislocations that do not require exploration of the sciatic nerve or internal fixation of the acetabulum; or for patients with old posterior dislocations but with greater mobility of the femoral head. On the contrary, if there is posterior dislocation with sciatic nerve injury or large acetabular fracture, or if the dislocated femoral head is above the acetabulum and the range of motion is very small, the posterior exposure approach may be considered. 1. Position, incision and exposure: Use the anterolateral exposure approach (see lower extremity bone and joint exposure approach). The patient lies supine, and the waist, back and buttocks of the affected side are elevated to an angle of 20° to 30° with the operating table. An anterolateral incision is made, the proximal side is peeled off under the periosteum of the medial and lateral muscles of the iliac wing, the distal side is entered between the sartorius muscle and tensor fascia lata, and the rectus femoris muscle is turned downward, that is, it touches the front of the hip joint. When using posterior exposure, the patient should be placed in a lateral or prone position, so that the patient's abdomen and the operating table form a 45° angle. Make a posterior incision, split the gluteus maximus muscle, first explore the sciatic nerve, separate and protect it. The piriformis muscle, obturator internus muscle, superior and inferior medullary muscle tendons are cut off from the greater trochanter, and turned medially to reveal the dislocated femoral head.

2. Separate the femoral head and neck. Generally, when the hip joint is dislocated posteriorly, the femoral head penetrates the posterior joint capsule and is located behind and above the acetabulum. When the anterolateral side is exposed, the assistant gently turns the injured limb, and the surgeon uses his fingers to find out the position of the femoral head and its relationship with the surrounding tissues. After removing the hematoma for fresh dislocation, carefully look for the reasons that hinder the reduction. Generally, the displaced fracture fragment blocks reduction, or a large joint capsule becomes involved in the acetabulum. Old dislocation requires separation of surrounding adhesions along the femoral head and neck. First, if there are no cords in the neck, you can make a small incision in the neck, then close to the bone and gradually separate it toward the femoral head until the femoral head and neck are free. Pay attention when separating: ① Do not cut and peel off the joint capsule of the distal 1/3 of the femoral neck to avoid damaging the blood vessels supplying the femoral head and neck; ② Cut the joint capsule in a T-shape as much as possible to allow the joints attached to the acetabulum to The sac should be kept 0.5 to 1.0cm for repair. ③Avoid damaging the sciatic nerve. When dislocation occurs occasionally, the sciatic nerve is placed in front of the femoral neck. If a cord-like object is touched during separation, it should be carefully separated and identified, or stimulated with a needle. If there is no muscle contraction, to prevent injury. When the posterior side is exposed, since the sciatic nerve has been separated and protected, and the femoral head and neck are exposed relatively directly, the joint capsule can be incised under direct vision to gradually separate the adhesions around the femoral head and neck. If there is a fracture of the posterior superior edge of the acetabulum, the gluteus minimus can be peeled off subperiosteally upward to expand the exposure.

3. Clean the acetabulum and externally rotate the injured thigh so that the femoral head does not cover the acetabulum. Then remove the hematoma, granulation, scar tissue, small bone fragments, round ligaments, etc. in the acetabulum with a knife. , scissors or curette to remove all. Be careful not to damage the articular cartilage during removal.

4. Fracture treatment: Posterior hip dislocation and fracture often occur in three situations: ① Completely free small bone fragments should be removed. ② Femoral head fracture: It is often an avulsion fracture of the round ligament. The defect caused by it on the femoral head is not on the load-bearing articular surface. The round ligament should be removed together to avoid hindering the reduction of the femoral head. Even if the fracture fragment is a load-bearing articular surface, resection is better than reduction. Because the fracture fragment will definitely cause avascular necrosis after reduction, leading to traumatic arthritis. ③ Acetabular fracture: It is often a triangular fracture fragment on the posterior upper edge of the acetabulum, which is rotated and displaced laterally and anteriorly. After reduction, fix it with 1 to 2 screws. The screws should be positioned obliquely upward, pointing toward the midline of the iliac crest to avoid penetrating the joint.

5. After the reduction is to separate the adhesions between the femoral head and the neck and thoroughly clean the acetabulum, the assistant fixes the pelvis and flexes the hip for traction. The surgeon pushes the femoral head in the direction of the acetabulum with his fingers to achieve reduction. There is no difficulty. If it cannot be reset, the reason should be identified. Generally, scars and adhesions are not peeled off enough, or the femoral head is caught by the contracted joint capsule, and should be further released. At this time, it is important to avoid forced manual reduction or use the leverage of instruments such as dissectors to avoid fractures or damage to the articular cartilage surface.

6. Repair the joint capsule and suture. After reduction, a dedicated person will maintain the position. The joint capsule is trimmed and repaired with suturing whenever possible. After hemostasis, suture layer by layer. 1. After dislocation without fracture, skin traction or bone traction is performed for 4 weeks. Walking with crutches will begin after 4 weeks, and weight-bearing will gradually begin after 6 to 8 weeks.

2. Perform bone traction after dislocation complicated by fracture, and perform functional exercises of quadriceps contraction as soon as possible. 6 to 8 weeks after surgery, traction is performed and hip joint function is exercised. Those with femoral head fractures can only bear weight 12 weeks after surgery.