Femoral neck fracture

Introduction

Introduction to femoral neck fracture

A femoral neck fracture is a femoral neck fracture caused by osteoporosis, degeneration of the hip muscle group in the elderly, unresponsiveness, or severe trauma. Femoral neck fractures often occur in the elderly. As people's life span increases, their incidence is increasing. Especially with the aging of the population, it has become a serious social problem. There are two major problems in the clinical treatment of fracture nonunion and avascular necrosis of the femoral head. So far, many unresolved problems remain in the treatment and results of femoral neck fractures.

basic knowledge

The proportion of illness: 2.2%

Susceptible population: mostly occurs in the elderly, the incidence of women is higher than that of men

Mode of infection: non-infectious

Complications: pelvic fracture joint dislocation shock ischemic necrosis traumatic arthritis femoral head necrosis

Pathogen

Causes of femoral neck fracture

Causes

External force factor (35%):

Due to the degeneration of the hip muscles in the elderly, the response is slow, can not effectively offset the harmful stress of the hip, and the hip is subjected to large stress (2 to 6 times weight), the local stress is complex and variable, so no need for much violence, If you slip on the ground, fall from the bed or suddenly twist the lower limbs, even in the absence of obvious trauma, fractures can occur.

Osteoporosis (20%):

The decrease in the strength of osteoporotic bone, combined with the nourishment of the vascular pores in the upper neck of the femoral neck, can weaken the biomechanical structure of the femoral neck and make the femoral neck fragile. Osteoporosis is one of the two basic factors that cause fractures in the elderly.

Accident (35%):

The young and middle-aged femoral neck fractures are often caused by serious injuries such as car accidents or falling from heights.

Pathogenesis

Femoral neck fractures occur mostly in the elderly, and the incidence of women is higher than that of men. Because the elderly have different degrees of osteoporosis, and female activities are relatively less than men, osteoporosis occurs earlier due to physiological metabolism, so even Injuries are not serious, and fractures can occur. Atkin (1984) 84% of patients with femoral neck fractures have varying degrees of osteoporosis. When Barth et al. performed artificial joint replacement for patients with femoral neck fractures, the medial femoral cortex was removed. Histological observation showed that compared with the control group, the bone unit was found to be significantly reduced, and the Harvard tube was widened. Frangakis studied the relationship between femoral neck fracture and osteoporosis in elderly women, and found that 50% of bone minerals were found in 65-year-old women. Below the fracture threshold, 100% of bone minerals in 85-year-old women are below the fracture threshold. It is generally believed that although not the only factor, osteoporosis is an important factor in the femoral neck fracture, and even some scholars It is believed that the femoral neck fracture of the elderly can be regarded as a pathological fracture. The degree of osteoporosis is the comminution of the fracture (especially the posterior lateral femoral neck powder). After the solid) and the fixed or not has a direct impact.

Most of the elderly patients with femoral neck fractures are mildly traumatic, and young people with femoral neck fractures are mostly caused by severe trauma. Kocher believes that the injury mechanism can be divided into two types: 1 when the fall is caused by direct impact, and 2 limbs are externally rotated. In the second mechanism, the femoral head is relatively fixed due to the anterior joint capsule and the patellofemoral ligament, the femoral head rotates backward, and the posterior cortex hits the acetabulum and causes a neck fracture. In this case, the posterior lateral bone often occurs. Cortical smashing, the violence caused by the femoral neck fracture in young people is much greater, the violent extension of the femoral shaft directly upwards, often accompanied by soft tissue injury, fractures often smash.

Prevention

Femoral neck fracture prevention

At present, there is no effective preventive measure for this disease. The prevention of this disease is mainly focused on preventing the occurrence of complications. It mainly advocates early non-invasive reduction, follows the early non-invasive anatomical reduction, and selects reasonable and effective internal fixation equipment and methods. Reduce local blood supply damage, improve blood flow, promote early healing of fractures, restore and establish blood vessels across the fracture line, and quickly participate in the repair of necrotic bone to avoid the occurrence of femoral head necrosis.

Complication

Femoral neck fracture complications Complications pelvic fracture joint dislocation shock ischemic necrosis traumatic arthritis femoral head necrosis

The common complications of this disease are as follows:

1. General complications of early or late orthopedics:

Including pelvic fractures, joint dislocation, visceral injury, other fractures, major bleeding, shock and so on.

2. Special complications:

Including femoral neck fracture non-healing, avascular necrosis of the femoral head, traumatic arthritis.

At the same time, the fracture may damage these blood vessels, causing necrosis of the femoral head, or the fracture does not heal.

The most common and serious complications are nonunion and femoral head necrosis.

1. Delayed healing and non-union Femoral neck fractures have not fully healed within 6 months after treatment. Delayed healing should be diagnosed. The incidence of nonunion after femoral neck fracture and age, fracture displacement, fracture line position and bone The severity of loosening is related to the severity of loosening. Many patients may be re-displaced. According to the survival of the femoral head, blood grafting or joint replacement should be performed. Head necrosis or existing displacement should be artificial joints. Replacement.

2. The avascular necrosis of the femoral head has healed, the femoral head necrosis has not been severely deformed, and the patients with mild clinical symptoms do not have to rush to surgery, so that they can maintain normal life and prevent excessive weight and exercise. Many patients can be in stock. After avascular necrosis of the bone, it still maintains normal life and light work for many years. Patients with osteoarthritis symptoms can take traditional Chinese medicine or non-steroidal anti-inflammatory drugs. After the pain and dysfunction are obviously aggravated, total hip arthroplasty should be considered.

Symptom

Symptoms of femoral neck fracture Common symptoms Joint swelling and pain Joint pain, hip flexion and external rotation, joint swelling, linear fracture

Symptom

Older people complain of hip pain after falling, do not dare to stand and walk, should think of the possibility of femoral neck fracture.

2. Signs

(1) Malformation: The affected limbs have mild hip flexion and external rotation deformity.

(2) Pain: In addition to spontaneous pain in the hip, the pain is more obvious when moving the affected limb. When the affected limb is heeled or the large trochanter is beaten, the hip is also painful, often under the midpoint of the inguinal ligament. tenderness.

(3) Swelling: There are many intracapsular fractures of the femoral neck fracture. There is not much bleeding after the fracture, and there is a thick muscle group surrounded by the joints. Therefore, the swelling is not easy to see in the appearance.

(4) dysfunction: displaced fracture patients can not sit up or stand after injury, but there are some cases of non-displaced linear fractures or inset fractures, still able to walk or ride a bicycle after injury, for these patients In particular, do not miss the diagnosis of a non-displaced stable fracture into a displaced unstable fracture due to missed diagnosis. The affected limb is shortened. In the displaced fracture, the distal end is displaced by the muscle group and displaced upward, and the affected limb becomes shorter.

(5) The ipsilateral large trochanter is elevated, which is manifested in: 1 horizontal trochanter above the iliac-ischial nodule line (Nelaton line), the horizontal distance between the 2 large trochanter and the anterior superior iliac spine is shortened, shorter than Jian side.

Examine

Femoral neck fracture examination

The diagnosis of the hip requires a lateral X-ray examination, especially for linear fractures or insertional fractures. X-ray examination is also indispensable for the classification and treatment of fractures. Some undisplaced fractures should be noted. The fracture line can not be seen on the X-ray film taken immediately after the injury. At that time, CT, MRI examination, or 2 to 3 weeks later, the fracture line was clearly revealed due to the absorption of some bone in the fracture. Therefore, In clinically suspected femoral neck fractures, although there is no fracture line on the X-ray film, the fracture should still be treated according to the insertion fracture. After 3 weeks, the film is reviewed again. Another easily missed condition is multiple injuries, which often occurs in this case. Young people, due to some obvious damage such as femoral shaft fractures, cover the femoral neck fracture, so the patient must pay attention to the hip examination.

First, in the inspection, the body can be found to have a large trochanter on the affected side, which is manifested in:

1. The large trochanter is above the sacral canal nodule;

2. The horizontal distance between the large trochanter and the anterior superior iliac spine is shortened, shorter than the temporal side, and the X-ray photograph can be clearly diagnosed, especially the hip joint and the lateral position, which can determine the fracture type, location, displacement and The choice of treatment method.

Second, the auxiliary examination of this disease is more X-ray examination, according to the shape of the femoral neck fracture is divided into embedded and dislocation fractures, the fracture line of these two types of femoral neck fracture can be expressed as dense lines and / or translucent lines, dense The fracture line indicates overlapping trabecular bone at the two fracture ends, while the translucent fracture line means separation between the two fracture ends.

1. There is no obvious dislocation of the embedded femoral neck fracture. Usually, the femoral neck is blurred and the dense fracture line is visible. The local trabecular bone is interrupted. The local cortical bone has small angulation or depression. The external rotation of the femoral shaft is small, and this type of fracture is obvious. It is a relatively stable fracture. Due to the different external force during the fracture, the femoral head can undergo different degrees of adduction, external rotation, anterior or posterior angulation, such as the presence of an angulated deformity at the insertion end, or a fracture. The slope of the line is large, the fracture end is separated, or the external femoral shaft is obvious, indicating that the fracture is unstable.

2, dislocation-type femoral neck fracture is more common, also known as adduction femoral neck fracture, two-fold end rotation and dislocation, femoral head backwards fracture end forward angle, femoral shaft external rotation upward dislocation, fracture line separation obvious.

Diagnosis

Diagnosis and diagnosis of femoral neck fracture

Traumatic history, hip pain, unable to stand walking, typical hip flexion, knee flexion and external rotation deformity, the affected side of the large trochanter above the Nelaton line, the horizontal distance between the large trochanter and the anterior superior iliac spine Shortening, X-ray film and CT examination can establish a diagnosis.

In the differential diagnosis, the main cause of this disease is to differentiate from the intertrochanteric fracture.

Injury postures of intertrochanteric fractures and femoral neck fractures, the clinical manifestations are roughly the same, the two are easy to be confused, should pay attention to differential diagnosis, in general, intertrochanteric fractures due to local blood supply is rich, swelling, obvious ecchymoses, pain More severe, more severe than the femoral neck fracture; the former's tender point is mostly in the large trochanter, the latter's tender point is mostly in the lower part of the midline of the ventral ligament, X-ray film can help identify.

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