Hip dislocation

Introduction to hip dislocation Dislocation of the hip is a serious injury because the hip joint is structurally stable and must have a strong external force to cause dislocation. Soft tissue damage is also severe at the time of dislocation, and often combined with other parts or multiple injuries. Therefore, the patients are mostly young adults with strong activities. Generally divided into three types: front, back and center dislocation. After dislocation, the femoral head was located on the Nelaton line (the anterior superior iliac spine and the ischial tuberosity line) before the dislocation. After the off-line is the posterior dislocation, the femoral head is squeezed to the midline, and the person who breaks the acetabulum and enters the pelvis is dislocated. Dislocation is the most common of the three types, and the injury should be treated as an emergency. The earlier the reduction, the better the effect. basic knowledge The proportion of illness: 0.012% Susceptible people: no specific population Mode of infection: non-infectious Complications: ischemic necrosis

Cause of hip dislocation

Violence (45%):

The posterior dislocation is due to the flexion of the hip joint, adduction, and violence from the long axis of the femur, which can tear the ligament, and the femoral head breaks through the joint capsule and causes dislocation.

Serious car accident (30%):

If the hip joint is in the outreach position, the femoral trochanter collides with the upper edge of the acetabulum, and as the fulcrum continues to abduction, the violence will impact along the long axis of the femoral head, and the anterior dislocation may occur, and the femoral head may stay in the closed hole or pubic iliac crest. For example, in the lower position, the legs are abducted, and when the cave is collapsed, the front dislocation may also occur.

Acetabular fracture (5%):

If the hip joint is in flexion and mild internal fixation, the same external force can cause the posterior margin of the acetabulum to fracture and the femoral head to dislocate backward. If the hip joint is in the middle or mild outreach position, violence can cause acetabular fracture, femoral head. Displacement along the fracture to the pelvic cavity is called central dislocation and is rare.

Hip dislocation prevention

The disease is caused by traumatic factors, pay attention to life safety, and avoid injury is the key to prevent this disease. Dislocation of the hip should be promptly treated. Because there are a few dislocations combined with acetabular fractures, X-ray film must be confirmed. Early reset is easy and the effect is good. Older, most of them have to be surgically reset, the effect is relatively bad. In addition, improper treatment can cause avascular necrosis of the femoral head, which seriously affects joint function.

Complications of hip dislocation Complications ischemic necrosis

Dislocation of the hip, especially after the treatment of congenital dislocation of the hip, is mostly rude and rude, the traction is not enough, the indications for the operation are not grasped, and the factors that hinder the reduction and improper fixation are not clarified. Most of them can be avoided. Common complications are:

(1) Re-dislocation often prevents the reduction factor from being eliminated, the X-ray appears illusion, careless when changing the plaster, the anteversion angle is too large or the acetabulum is poorly developed, so even after the reduction, it is easier to dislocate.

(B) the avascular necrosis of the femoral head is mainly due to rude or excessive surgical trauma, damage to the blood supply of the femoral head; strong abduction during fixation; insufficient traction or adductor muscle before reduction, waist The muscles are not loosened, the femoral head is over-stressed after resetting, and some reasons are unknown.

(C) Hip osteoarthrosis is a late complication, usually after surgery in older children, it is often difficult to avoid some complications after adulthood.

(4) Separation of femoral condyle, upper femoral fracture, sciatic nerve injury, etc. These are caused by insufficient traction, violent or anesthesia when resetting, etc., and can generally be avoided.

Symptoms of hip dislocation Common symptoms Flexion of the hips and external rotation of the joints and pain of the joints of the hips can be seen on the outside of the hips. Hemorrhagic episodes of the hips, soreness, discomfort, trochanteric pain, hip swelling, tenderness, depression, thighs or knees...

Symptoms:

1. Suffering from hip swelling and pain after trauma, limited activity.

2. After dislocation, suffering from hip flexion, adduction, internal rotation, shortening deformity.

3. Before dislocation, suffering from hip extension and abduction external rotation deformity.

4. Center dislocation, short limb deformity of the affected limb, limited hip activity.

Hip dislocation examination

The auxiliary examination method for this disease is mainly image examination, including the following methods:

1, X-ray inspection:

X-ray plain film is the most basic method for diagnosing hip dislocation and fracture. Most of the dislocation X-ray films can be correctly displayed. However, the hip joint structure is complicated and the front and rear structures overlap, although most hip fracture X-ray films Can determine the presence or absence of fracture, but it is difficult to show the exact extent of the fracture, the exact location, the exact direction of displacement and the relationship with the joint capsule, and the semi-dislocation of the femoral head, the posterior acetabular fracture, small fractures in the joint X-ray plain films such as fragments, dome fractures, and small avulsion fractures of the acetabulum or femoral head are easily missed.

2. Conventional CT:

Conventional CT can make a correct diagnosis for most hip dislocations. The advantage of X-ray film is that it can clearly show the direction and extent of dislocation. More importantly, it can clearly and accurately show whether there is broken in the hip joint. The presence of bone fragments directly determines the patient's treatment plan and prognosis. If the embedded intra-articular bone fragments cannot be detected and removed in time, the avascular necrosis rate of the femoral head and the traumatic arthritis are prolonged with time. The incidence has increased significantly.

3, 3D-CT :

The biggest advantage of CT 3D reconstruction is that it displays the surface of the joint stereoscopically, the image is realistic, and the image can be rotated at any angle to obtain the best exposed part, but 3D-CT also has some shortcomings:

1 In the three-dimensional reconstruction of the hip joint, 3D-CT may have a "false fracture" sign.

2 The spatial resolution of the 3D reconstruction is poor, and the details of the image are easily lost during the reconstruction process. The linear fracture (< 2 mm) with no obvious shift is not easy to display.

3 pairs of intra-articular broken bone fragments can also be missed.

Diagnosis and diagnosis of hip dislocation

diagnosis:

1. There is a history of obvious trauma.

2. Suffering from hip swelling, pain, and limited mobility.

3. Suffering from hip flexion adduction, internal rotation deformity, or abduction external rotation deformity.

4. X-ray film: visible dislocation, or combined with acetabular fractures.

Hip dislocation is clinically divided into three types: posterior dislocation, anterior dislocation, and central dislocation. The central type of dislocation is mainly caused by acetabular fractures due to pathological changes in the injured part. Therefore, it is often classified as a pelvic fracture. The distinction between anterior and posterior dislocation is based on the pre- and post-Nile's line of the femoral head. The incidence rate is 10 to 20 times that of the former dislocation.

Differential diagnosis:

Because the anatomical structure of the hip joint is stable, dislocation often requires strong external force. Therefore, multiple dislocations in other parts of the dislocation are also easy to be missed and misdiagnosed, especially in some complicated injuries, such as multiple fractures of the extremities and craniocerebral injury. , or ipsilateral femoral shaft fractures, and simple hip dislocation missed diagnosis, although misdiagnosed, there are few reports, clinically often need to identify with femoral neck fracture.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.