What Is Femoroacetabular Impingement?

The hip joint is a pestle and mortar joint, surrounded by tough ligaments and strong muscle flaps, so it is very stable. Only under the effect of indirect violence will dislocation through the weak area between the ligaments. Most of them are young adults and are injured by strong violence during work or in a car accident. Dislocation of the femoral head after the Nelaton line is posterior dislocation; anterior dislocation is the former. Twist, leverage or conducted violence can cause it. Conducted violence causes the femoral head to hit the bottom of the acetabulum, and the prolapse into the pelvis is a central dislocation.

Basic Information

English name: dislocation of hip joint
Visiting department: orthopedics

Multiple groups: Young adults
Common causes: Suffered strong violence
Common symptoms: Posterior dislocation of hip, anterior dislocation of hip, central dislocation

Causes of hip dislocation

Most were injured by the impact of strong violence.

Hip dislocation

In the femoral head, the weak area between the patellofemoral ligament and the sitting femoral ligament is often punctured and dislocated, resulting in tearing of the posterior joint capsule and round ligament.

2. Anterior hip dislocation

Mostly due to the extreme abduction and outward rotation of the hip joint, the lever formed by the greater trochanter abutting the acetabular margin causes the weak area between the femoral head to the patellofemoral ligament and the pubic femoral ligament to break through the joint and prolapse.

3. Center dislocation

When the violence is transmitted, the femoral head hits the bottom of the acetabulum, and the dislocation to the pelvis is a central dislocation.

Clinical manifestations of hip dislocation

Hip dislocation

The femoral head is mostly punctured by the weak area between the sacral ligament and the sciatic ligament, causing tears in the posterior joint capsule and round ligament. If the hip joint is exposed to conductive violence in a slightly outward booth, the posterior margin of the acetabulum is prone to fracture due to the impact of the femoral head, or the anterior and lower fracture of the femoral head. No matter where the fracture is, it will affect the stability of the joint, so the classification is mainly based on the condition of the combined fracture.

(1) Type dislocation is not associated with or combined with acetabular fractures;

(2) Type dislocation with massive fracture of posterior lip of acetabulum;

(3) Type III dislocation with extensive acetabular comminuted fracture;

(4) Type IV dislocation with femoral head fracture.

Hip swelling and pain, limited mobility after trauma, hip flexion, adduction, internal rotation, and short contraction deformity.

2. Anterior hip dislocation

It is far less common than posterior dislocation. Because the front is mainly for ligament maintenance, it should not be combined with fractures. Anterior dislocation suffers from hip extension and abduction spinal deformity.

3. Center dislocation

Short limb deformity and limited hip movement.

Hip dislocation examination

1. X-ray inspection

X-ray films are the most basic method for diagnosing hip dislocations and fractures. Most X-ray films of hip dislocations can be displayed correctly.

2.CT inspection

The correct diagnosis can be made for most hip dislocations. Compared with X-rays, it has the advantage of clearly showing the direction and degree of dislocation. More importantly, it can clearly and accurately show whether there are bone fragments in the hip The presence.

The biggest advantage of three-dimensional reconstruction of CT is that the surface of the joint is displayed three-dimensionally, the image is realistic, and the image can be rotated at any angle to obtain the best exposed part.

Hip dislocation diagnosis

There is a clear history of trauma, and pain in the affected area is limited. The affected limb was shortened, and the hip joint was deformed, adducted and deformed. The prosthetic femoral head can be felt on the buttocks. X-ray examination and CT examination can confirm the diagnosis.

Differential diagnosis of hip dislocation

Clinically, it is often necessary to identify the femoral neck fracture.

Complications of hip dislocation

The complications of hip dislocation, especially after congenital hip dislocation treatment, are mostly caused by rough manipulation and insufficient traction, surgical indications are not grasped, and factors that hinder reduction and improper fixation are not clear. Most can be avoided. Common complications are:

1. Redislocation is often not eliminated due to obstacles to reduction. X-rays appear artifacts, careless when changing plaster, too large anteversion angle or acetabular dysplasia, so it is easier to relocate even after resetting.

2. Complications such as ischemic necrosis of the femoral head are mainly due to rough manipulation or excessive surgical trauma, which damage the blood supply to the femoral head; strong extreme abduction during fixation; insufficient traction before reduction or adductor or iliopsoas muscles Unrelieved, excessive pressure on the femoral head after reduction and so on.

3. Hip osteoarthropathy is a late complication. Generally, it is more difficult to avoid similar complications in older children after surgery.

4. Femoral skull condyle separation, upper femoral fracture, sciatic nerve injury, etc. These are all caused by insufficient traction. Violence or too shallow anesthesia are used for reduction, which can generally be avoided.

Hip Dislocation Treatment

1. Simple dislocation treatment

(1) Generally, posterior dislocation of the hip joint can be reset manually, with few difficulties. The reduction method is stable and reliable with traction of hip and knee flexion along the femoral axis. Allis method is supine traction and Stimson method is prone traction. When resetting, the method should be slow, continuous use of traction, violent or sudden steering is strictly prohibited, and it is not allowed to forcibly reverse when there is resistance. If the traction method is invalid, you can use the rotating "?" Question mark method instead.

(2) When the anterior dislocation of the hip joint is pulled along the axis of the affected limb, the operator pushes the femoral head from front to back to move it toward the acetabulum, and adducts the lower limb to make it acceptable.

(3) Central dislocation should be reduced with bone traction for 4 to 6 weeks. If severe traumatic arthritis occurs late, artificial joint replacement or joint fusion can be considered.

2. Old hip dislocation

Because the acetabulum is filled with fibrous scars and the surrounding soft tissues are contracted, it is not easy to successfully reset. The treatment method can be decided according to the dislocation time, local lesions and the wounded. For severe articular surface damage, hip fusion or artificial joint replacement can be performed according to the occupation of the patient.

Prognosis of hip dislocation

Dislocation of the hip joint should be promptly diagnosed. Because there are a few dislocations associated with acetabular fractures, early reduction is easy and the effect is better. Older people, most of them need surgery reduction, the effect is relatively poor. In addition, improper treatment can cause ischemic necrosis of the femoral head and severely affect joint function.