Hip dislocation

Introduction to posterior dislocation of the hip The hip joint is an ankle joint consisting of the acetabulum and the femoral head. The acetabulum is deep and large. It can accommodate most of the femoral head. The two are close to each other, forming a vacuum, attracting each other, and the joint capsule and surrounding ligaments are stronger. It constitutes a fairly stable joint with a low incidence of dislocation. The anterior wall of the hip joint capsule has a strong patellofemoral ligament, the inner upper wall has a pubic capsular ligament, and the posterior superior wall has a sciatic sac ligament, but the inner and lower walls and the posterior wall The inferior wall lacks ligaments, which are relatively weak, and it is easy to dislocate from these two places. The simple hip dislocation without acetabular fractures is only the first two. Lateral dislocation is most common in clinical practice. basic knowledge The proportion of the disease: the incidence of the disease caused by trauma is about 0.04% - 0.07% Susceptible people: no specific population Mode of infection: non-infectious Complications: fractures femoral head fractures acetabular fractures traumatic arthritis

Causes of posterior dislocation of the hip

(1) Causes of the disease

Mostly caused by indirect violence.

(two) pathogenesis

Mostly caused by indirect violence, when the hip flexes, adducts and rotates the femoral shaft, the upper lateral side of the femoral head has beyond the posterior edge of the acetabulum, and the anterior border of the femoral neck is immediately adjacent to the acetabular rim, which is formed here. The lever of the fulcrum, when there is strong violence hitting the front of the knee (such as when the thigh on the other side of the car is placed on the other side of the thigh, suddenly braking, the passenger's knee hit the back of the front seat, etc.), the femoral shaft continues to rotate And adducted, the femoral head wears the posterior wall of the joint capsule due to the leverage, and the acetabulum is dislocated, forming dislocation. The sports occasionally dislocation after the hip due to human contact, such as football, when the ball is blocked. The knee and hip are slightly adducted. Suddenly, a violent action on the back of the humerus or pelvis can cause dislocation of the hip. The dislocation of the hip caused by a traffic accident is common in the collision of the fender against the knee or femur. Violence is transmitted to the hip joint through these anatomical structures, so the knee or femur injury is noticed and the hip dislocation is neglected. Due to the posterior dislocation of the hip with the femoral shaft fracture, the hip dislocation is missed, and the proximal dislocation is closed. Become a distraction for watching Outreach femoral shaft fractures, but you can find a detailed clinical examination dislocation of the hip external rotation deformity, and X-ray photographs the better to confirm the diagnosis.

Hip dislocation prevention

1. Have a reasonable way of living and working: usually drink milk (several times), get more sun, and add calcium if necessary. Labor intensity should be adjusted or the type of work that causes the symptoms to worsen should be replaced to eliminate or avoid adverse factors such as strenuous exercise.

2. Avoid excessive load: avoid excessive load on the affected joints, and obese people should lose weight. Patients with knee and hip involvement should avoid standing, squatting and squatting for long periods of time.

3. Choosing the right shoes: It is best for the elderly to wear shoes with soft belt heel. The height of the heel of the shoe is about 2cm higher than the forefoot of the sole. The soles of the elderly are slightly larger, and must have non-slip ripples to avoid falling. .

Complications of posterior dislocation of the hip Complications fracture femoral head fracture acetabular fracture traumatic arthritis

Fracture

Hip dislocation can be combined with acetabular fracture or femoral head fracture, and occasional femoral shaft fracture and hip dislocation occur simultaneously.

2. Nerve damage

In about 10% of patients with posterior hip dislocation, the sciatic nerve may be contused by the posterior, displaced femoral head or acetabular fracture block, causing paralysis of the affected side of the sciatic nerve. After dislocation, about 3/4 of the cases will gradually recover. If paralysis does not improve after hip dislocation, and there is a suspected large or comminuted acetabular fracture in the continuous compression of the nerve, early surgical exploration is required.

3. Avascular necrosis of the femoral head

Joint capsule tear and round ligament rupture, which are unavoidable due to hip dislocation, may affect the blood supply of the femoral head. Avascular necrosis occurs in 10% to 20% of cases, and changes can be seen on X-ray photographs around 12 months. It has been confirmed that early reduction can shorten the time of blood circulation damage of the femoral head, and it is the most effective way to prevent femoral head necrosis. The clinical manifestations are persistent inguinal discomfort and hip internal pain, and exercise is limited. If measures are taken, necrosis will continue to deteriorate. In the end, it will inevitably lead to severe traumatic arthritis. In severe cases, joint fusion and artificial joint replacement should be performed.

4. Traumatic arthritis

This is a late complication, which is an inevitable result of ischemic necrosis. It can also occur in patients with hip dislocation and articular surface fracture. Generally speaking, patients should avoid any excessive weight during 2 to 3 years after dislocation. Or reduce the incidence of traumatic arthritis.

5. Dislocation

Regardless of whether the procedure is reset or after a surgical reduction, there is a possibility of re-dislocation. Although the incidence is low, it should be vigilant.

Post-hip dislocation symptoms Common symptoms Hip dislocation hips can be touched up... Shock

There is a clear and quite serious history of trauma. Because the patellofemoral ligament on the anterior side remains intact, the affected limb is flexed, adducted and internally deformed. If the patellofemoral ligament is broken at the same time (this is less), the affected limb External rotation, pain in the affected part, joint dysfunction, elastic fixation, shortened limb, upper femoral head accessible to the buttocks, large trochanter above the Nelaton line, X-ray examination showing the femoral head at the hip The outer top of the cockroach.

Classification: Thompson and Epstein divide hip dislocation into 5 types

Type I: Dislocation with or without minor fractures.

Type II: Dislocation with isolated large fractures of the posterior border of the acetabulum.

Type III: Dislocation with comminuted fracture of the posterior border of the acetabulum, with or without large fractures.

Type IV: Dislocation with acetabular bottom fracture.

Type V: Dislocation with a femoral head fracture.

In addition, the injury caused by hip dislocation is strong, so there may be fractures of the ipsilateral femur, sciatic nerve injury and shock, and Dehne and Immermann collected 42 cases of ipsilateral Femoral fractures and dislocations, in 17 of 42 cases, until the hip joint function has been irreversibly lost 4 to 6 months after injury, dislocation is found, therefore, in the treatment of such injured patients should try to take X-rays The slice determines the ipsilateral or contralateral fracture or dislocation. The injury to the sciatic nerve is often transient or incomplete. Observed by Aufranc, Narton and Row, after the hip. About 27% of patients with dislocation have long-term signs of sciatic nerve involvement. 69% of these patients are transient, only 29% are persistent incomplete injuries. The most common sacral nerve breaks in the injury, shock caused by dislocation, should attract attention. In case of missing diagnosis and treatment.

Examination of posterior dislocation of the hip

No relevant laboratory tests. X-ray examination can confirm the diagnosis, except for fractures.

Diagnosis and identification of posterior dislocation of hip

Obvious history of trauma, flexion of the lower limbs of the affected side, internal rotation and shortening deformity, the large trochanter is above the Nelaton line, the buttocks can be licked and the femoral head is fixed. The affected limb is elastically fixed. X-ray can confirm the diagnosis and exclude the fracture. CT examination can make a diagnosis of bone fragments in the joint.

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