Fractures of the femoral neck (femoral neck fractures)

Anatomy and blood supply

The hip joint is one of the largest joints in our body.
Due to the fact that man, as a result of evolution, stood on two legs, the hip joint is the main supporting joint and bears a significant load when walking, running, and carrying heavy loads. The shape of the hip joint can be imagined as a ball located in a deep round socket. The socket of the hip joint is formed by the pelvic bone and is called the acetabulum. It contains the head of the femur, which is connected to the body of the femur by a neck. Often the neck of the femur is called the “femoral neck,” but this is jargon. Somewhat below the femoral neck are bony prominences called the greater and lesser trochanters. Powerful muscles are attached to them. Around the joint there is a joint capsule, which contains ligaments that strengthen the hip joint. On the one hand, these powerful ligaments are attached at one end to the pelvic bone and at the other end to the femur. Another strong ligament (called the ligament of the femoral head, often called the round ligament) connects the head of the femur to the floor of the acetabulum.

The hip joint is covered by the muscles of the gluteal region in the back and the muscles of the anterior thigh in the front. The head of the femur, located in the acetabular cavity, is covered with articular cartilage. The articular cartilage in the hip joint averages 4 mm in thickness, has a very smooth whitish surface and a dense elastic consistency. Due to the presence of articular cartilage, friction between the contacting articular surfaces is significantly reduced.

A bone can only live when it receives blood. The blood supply to the femoral head is carried out in three main ways:

1. Vessels going to the bone through the joint capsule
2. Vessels running inside the bone itself
3. A vessel passing inside the ligament of the head of the femur. This vessel works well in younger patients, but in adulthood this blood vessel usually thins and closes.

When the neck of the femur is fractured (fracture of the femoral neck), not only the bone is damaged, but also the vessels are torn, and the bone fragment (the head and part of the neck of the femur), deprived of blood supply, can resolve and gradually disappear. This condition is called osteonecrosis or avascular necrosis of the head and neck of the femur. In addition, a bone fragment of the head and neck of the femur, deprived of blood supply, may not heal, i.e. a condition such as nonunion of a fracture or the so-called false joint will arise. The risk of nonunion after a femoral neck fracture is especially high in older people in whom the vessel running inside the femoral ligament is closed.

In elderly people, when the femoral neck or femoral head is fractured, the bone fragment is deprived of blood supply and the fracture may not heal at all.

You can learn more about the anatomy of the hip joint in a separate article on our website (click to go to the article on anatomy).

Causes of hip fracture

Before examining the causes, it is important to identify the factors that contribute to this type of injury:

• hormonal disbalance;
• deposition of cholesterol plaques on the walls of blood vessels;
• the presence of excess weight, which provokes an increase in the load on the musculoskeletal system;
• insufficiency/excess of physical activity;
• lack of coordination;
• inadequate daily diet.

The probable causes of this type of damage are:

• road accident;
• production situations;
• various types of falls.

Fracture rate and mechanism of injury

Femoral neck fractures are a serious medical problem. This is due to its high frequency (statistics show that this type of fracture accounts for 6% of all fractures) and the truly dramatic consequences that this fracture can entail. A hip fracture is 90% common among elderly people over 65 years of age; women suffer from these fractures three times more often than men. Unfortunately, even in developed countries, 30% of elderly patients die within a year of a hip fracture. This is due to the fact that if the patient does not undergo surgery, then he is forced to be bedridden for a long time, which in elderly patients has a catastrophically detrimental effect on health: concomitant diseases worsen, heart failure worsens, and pneumonia occurs against the background of reduced ventilation (the so-called hypoventilation or "congestive" pneumonia).

The causes of hip fracture differ greatly between younger and older patients. In older patients, fractures occur due to a decrease in bone strength, the so-called osteoporosis, which develops after menopause. Osteoporosis also develops in older men, but usually to a lesser extent. Bones susceptible to osteoporosis can break even with a normal fall out of the blue. Risk factors also include neurological diseases, impaired vision, cancer, malnutrition and reduced physical activity.

In young patients, fractures of the femoral neck (“femoral neck”) are associated with so-called high-energy trauma—road traffic accidents, falls from great heights, etc.

Diaphyseal fractures (damage to the shaft of the femur)

This type of fracture is the most severe injury of all types of injuries to the femur. In addition to the main reasons, it can be noted that athletes often receive it during intense training or competition. Symptoms of a diaphyseal fracture:

• severe pain, swelling and hematoma at the site of injury;
• deformation and shortening of the limb;
• pathological bone mobility.

To prevent the development of traumatic shock and blood loss, emergency assistance must be provided quickly. It consists of securely fixing the injured limb with a splint and administering painkillers.

Classification of fractures

In order to standardize approaches to the treatment of femoral neck fractures, several classifications have been developed. Each of them takes into account any fracture criterion that influences the further course of the disease and, accordingly, the choice of treatment method.

The course of the fracture line in the femoral neck is important for prognosis. The closer it is to the head of the femur, the less likely it is that sufficient blood supply to its head will remain. This increases the risk of avascular necrosis of the head (bone death) and nonunion of a femoral neck fracture. This risk especially increases in older people, whose blood supply is already reduced.

Types of fractures according to their anatomical location

• basicervical (located at the base of the femoral neck, fractures farthest from the head),
• transcervical (passing directly through the neck of the femur)
• subcapital fractures (located in close proximity to the head of the femur).

Left: subcapital fracture of the femoral neck, the fracture line runs just below the head. This option is the most unfavorable in terms of prognosis for fusion, since the head is very poorly supplied with blood. In the center: transcervical fracture of the femoral neck, the fracture line runs along the middle of the neck. Right: basicervical fracture, the fracture line passes at the very beginning of the femoral neck. Compared to the previous two options, it is more favorable in terms of prognosis for fusion.

However, it is important not only how the fracture line is located in the femoral neck, but also its angle. In particular, the more vertical the fracture line, the higher the chances that the fracture will displace and fail to heal. To describe fractures according to this criterion, the classification proposed by F. Pauwels in 1935 is used. The first degree corresponds to an angle of less than 30°, the second to an angle from 30 to 50°, and the third to an angle of more than 50°.

Various options for the fracture angle line (classification by F. Pauwels).

Garden's classification of femoral neck fractures is often used. It divides fractures of the femoral neck depending on the displacement of fragments into degrees - from I (incomplete fracture without displacement) to IV (complete separation of fragments).

Garden classification of femoral neck fractures.

It can be generalized that the more vertical the fracture line of the femoral neck is, the closer the fracture is to the head of the femur, and the older the patient, the higher the chance that the fracture will not heal.

Symptoms

A femoral neck fracture can be suspected by the typical mechanism of injury, characteristic clinical signs, and confirmed by x-rays.

Elderly patients, as a rule, report an accidental fall and bruise in the area of ​​the hip joint (the greater trochanter - a bony protrusion that can be felt along the outer surface of the thigh in its upper third).

In younger patients, fractures occur due to more severe injuries, such as falls from a height or car accidents.

At rest, the pain is mild. Pain in the hip joint intensifies when trying to move the leg. There is usually no bruising in the hip area. Tapping the heel causes pain in the hip joint and groin.

When the femoral neck is fractured, the leg can be shortened due to the displacement of bone fragments. In addition, the outer edge of the foot can lie on the surface of the bed (external rotation) - also due to displacement of fragments. In this case, the patient cannot independently remove the leg from this position. In addition, in the vast majority of cases, the patient cannot independently lift the heel from the surface of the bed. This symptom got its name - “sticky heel symptom.”

External rotation and shortening of the leg due to a fracture of the femoral neck - the foot of the left leg lies on the bed with its outer edge. You can also note the shortening of the legs.

An accurate diagnosis of a fracture of the neck of the femur (femoral neck) can be made using radiographs. In some cases, computed tomography may be needed to clarify the nature of the displacement of fragments.

Radiographs of various types of fractures

In some unclear cases, when standard radiographs raise doubts about a femoral neck fracture, the diagnosis can be confirmed using MRI or scintigraphy, but in the vast majority of cases they are not necessary.

Magnetic resonance imaging for a basicervical, almost intertrochanteric fracture of the femoral neck

Diagnostic procedures

The implementation of diagnostic procedures is carried out by a traumatologist. The patient can also contact a therapist with the symptoms of a hip fracture, however, the therapist will be required to refer the patient to a specialist.

To confirm the diagnosis, an x-ray examination is prescribed. If there is doubt, computed tomography and magnetic resonance imaging are additionally used.

A standardized diagnostic examination plan consists of items such as:

1. Studying the patient's complaints, collecting a detailed medical history.
2. Examination, determination of clinical manifestations indicating the presence of injury.
3. Purpose of instrumental research.

The diagnosis is made if there are x-ray results confirming damage to the bone tissue of the hip. To clarify the result, the examination is done in several projections, which makes it possible to detail the clinical picture.

It is worth noting that almost all diagnosed cases require surgical intervention, and therefore, a patient who comes with a problem of this kind is prescribed a full examination of the body, which makes it possible to identify somatic pathologies and assess the existing anesthetic and surgical risks.

Treatment Options

Approaches to the treatment of femoral neck fractures have changed along with the development of traumatology and surgical orthopedics. Initially, there were no alternatives to conservative treatment. The surgeon's arsenal included immobilization, i.e. immobilization of the joint with the help of various bandages and skeletal traction, which makes it possible to compare fragments during long-term implementation. All these methods slightly increased the chance of healing of the femoral neck fracture and were accompanied by a large number of complications. Gradually, techniques began to appear that made it possible to fix bone fragments. These methods, as they improved, found more and more supporters. Currently, the “golden” standard for the treatment of such fractures, with rare exceptions, is the surgical method.

Conservative treatment of femoral neck fractures can only be used if the patient has serious concomitant diseases, such as, for example, a recent myocardial infarction. Another exception is if for some organizational reasons it is impossible to perform the operation (for example, there is no equipment or a competent surgeon) and if the femoral neck is fractured without displacement, and the fracture line is located at an angle of less than 30 degrees, i.e. almost horizontally and such a fracture of the femoral neck does not tend to shift.

In general, conservative treatment of femoral neck fractures is a method of despair, and one must clearly understand that often surgery in elderly patients is aimed at saving lives, because being bedridden for many months, such patients gradually “fade away” and cases of death are not uncommon.

Possible complications with conservative treatment

The main complication of conservative treatment of fractures of the femoral neck (“femoral neck”) is nonunion of the fracture. As we have already noted, this occurs due to the fact that the head is often deprived of blood supply and the fracture of the femoral neck simply cannot heal.

Ununited fractures of the necks of both femurs after unsuccessful conservative treatment. Lysis has occurred, i.e. resorption of the femoral necks. Subsequently, with this variant of the course, lysis of the femoral heads will also occur.

The main reason for possible complications during conservative treatment of a femoral neck fracture is the patient’s loss of ability to move independently. Combined with advanced age, forced bed rest becomes fatal for many patients.

Elderly people on bed rest due to a hip fracture often develop congestive pneumonia, which is difficult to treat. Pneumonia leads to respiratory failure and can lead to the death of the patient.

When forced to stay in bed for a long time, elderly patients with hip fractures often develop bedsores, which are usually located in the sacrum and buttocks. Development of pressure ulcers, i.e. areas of tissue necrosis are associated with impaired blood circulation in them, caused by prolonged pressure on the skin and underlying tissues.

Patients with a hip fracture often experience various psycho-emotional disorders, including the development of psychosis and depressive states.

A serious complication of a femoral neck fracture is the development of deep vein thrombosis of the lower extremities, also caused by prolonged immobility of the patient, which occurs during both surgical and conservative treatment of femoral neck fractures. The danger of thrombosis is that blood clots formed in the veins can travel through the bloodstream to the lungs, causing pulmonary embolism, a fatal complication.

The most effective method of preventing or reducing the likelihood of all these complications is to quickly mobilize a patient with a hip fracture - the person needs to be put on his feet!

Thus, surgical treatment for hip fractures, which allows the patient to be activated, put on his feet and begin to walk with additional support on crutches or a walker, often saves the patient’s life and is carried out for health reasons. In young patients with hip fractures, surgery can reduce the likelihood of fracture nonunion, achieve better functional results, and more quickly return to their normal lifestyle.

Surgical treatment

Currently, there are several options for surgical treatment of femoral neck fractures. The choice of a specific technique depends on the patient’s age, concomitant diseases, and the patient’s general health.

This table provides approximate criteria that can guide a doctor when choosing a particular treatment method for fractures of the femoral neck. It must be borne in mind that each patient requires an individual approach, taking into account a much larger number of criteria, and this table shows only approximate and possible options.

Let us tell you in more detail about each of the possible treatment methods for a femoral neck fracture.

Reposition is the comparison of bone fragments. Before fixing bone fragments from a femoral neck fracture, they need to be compared. In some cases, in order to increase the chances of healing of a femoral neck fracture, the reduction is performed non-anatomically, i.e. do not restore the original, pre-fracture position of the bone, but the special one – i.e. the fragments are shifted so that the fracture becomes more “simple”. In particular, they try to give the femoral neck fracture lines a more “horizontal” position, which reduces the risk of displacement in the postoperative period. After reduction is completed, the fracture is fixed.

Special reduction, in which the displacement of fragments is given a more “horizontal” position

In young patients with femoral neck fractures, fixation is most often performed with three large screws. The screws can be cannulated, i.e. have a hollow channel inside it, like an injection needle. When using them, several thin metal wires are first inserted into the bone, the most well-positioned ones are selected, screws are placed on these wires and screwed into the bone, as if using a guide.

Osteosynthesis with three screws for femoral neck fractures in young patients. This introduction ensures the speed and accuracy of the operation. Screws inserted in this way compress the bone fragments between themselves, which increases the stability of fixation and the likelihood of fusion.

Fixation of fragments in a femoral neck fracture can be performed with more massive metal structures (compression femoral screw DHS, compression condylar screw DCS), but these are quite bulky fixators, and if only the femoral neck is broken, traumatologists prefer to use several separate screws.

Osteosynthesis of a femoral neck fracture with the DHS system (Dynamic Hip Screw)

The previously used fixation for femoral neck fractures using a bundle of thin pins and a three-blade nail is now practically not used as unreliable, and preference is unconditionally given to more modern and stable methods of fixation.

You can watch videos of rehabilitation exercises after osteosynthesis of the femoral neck on our website (click to go to the article on rehabilitation).

In cases where, after a femoral neck fracture, the risk of complications such as nonunion of the fracture, osteonecrosis of the head and neck of the femur (avascular or aseptic necrosis), which is more common in elderly patients, with significant displacement of the fragments, complex fracture of the femoral neck, optimal The treatment is hip replacement.

When hip arthroplasty is performed for a femoral neck fracture, only the neck and head of the femur are replaced (unipolar arthroplasty) or both the neck and head and the acetabulum are replaced (bipolar or total arthroplasty).

When both components of a joint (head and socket) are replaced, endoprosthesis replacement is called total. The components of the endoprosthesis can be fixed by hammering into the bone during surgery - the so-called cementless press-fit fixation. Subsequently, the bone grows into the porous surface or special grooves of the endoprosthesis. The cup of the endoprosthesis (the pelvic component that replaces the acetabulum), when fixed without cement, also has a porous coating for subsequent bone growth. The cup can be additionally fixed with screws.

The cementless fixation method is more preferable for young patients: it provides good fixation due to high bone density and is more favorable in relation to re-operation to replace the endoprosthesis. Although the service life of endoprostheses is constantly increasing due to technological developments, they still remain limited and young patients may require elective replacement of the endoprosthesis in the future.

Total (bipolar, i.e. both the femoral neck and the acetabulum are replaced) cementless endoprosthesis replacement for a femoral neck fracture. On the left is a postoperative radiograph. On the right is the appearance of a cementless endoprosthesis with a porous coating. One of the most common arrangements of a cementless endoprosthesis is presented, consisting of a cup, an insert made of high molecular weight polyethylene, a metal head and a leg.

In elderly patients with femoral neck fractures, fixation of endoprostheses is often chosen using a special polymer cement, which provides quick and reliable fixation even in the face of decreased bone strength and density, often observed in this group of patients. However, if concomitant diseases in an elderly patient with a femoral neck fracture are not critical, and the bone condition is good, then a cementless endoprosthesis can be installed.

Cemented endoprosthesis

The difference between cemented and cementless models of hip joint endoprostheses lies in the principle of their fixation. The cementless components of the endoprosthesis are covered with a porous or hydroxyapatite coating, installed into the bone using the “tight fit” method, and subsequently the bone grows into the surface of the implant. Cemented endoprostheses are fixed in the bone with special polymer cement, usually made from polymethyl methacrylate.

Cemented and cementless fixation of endoprosthetic legs

In patients with femoral neck fractures who are even more advanced in age, physically weakened, and who need to undergo a more sparing operation, only the neck and head of the femur are usually replaced, preserving their own acetabulum. This reduces the duration of the operation, reduces blood loss and improves the tolerability of the operation.

When choosing this method of treating a femoral neck fracture, unipolar (unipolar) endoprostheses can be used, the head of which is in direct contact with the surface of the cartilage of the glenoid cavity. This is the most gentle operation; it is performed on elderly patients in the most serious condition. The disadvantage of this operation is that direct contact of the head with the endoprosthesis leads to fairly rapid wear of the articular cartilage.

Its wear can be reduced by reducing friction between the cartilage and the head of the endoprosthesis. To do this, the head is made in the form of two hemispheres, nested one inside the other (like nesting dolls), and movements in such a joint occur between the hemispheres of the head, which reduces wear and destruction of the articular cartilage. Such endoprostheses are called bipolar.

Bipolar and monopolar hip replacements, used in elderly, weakened patients with femoral neck fractures and a high risk of complications - with this model, cup replacement is not performed, i.e. the cup of the endoprosthesis is not installed and the head of the endoprosthesis slides along the cartilage of the acetabulum

X-ray of the hip joint of a patient who underwent bipolar arthroplasty for a femoral neck fracture. The cup was not installed, the head of the endoprosthesis slides along the cartilage of the acetabulum

You can learn about how to prepare for endoprosthetics, what are the rules and features of the postoperative and rehabilitation period after hip replacement in a separate article on our website.

You can watch a video of rehabilitation exercises after hip replacement in another article on our website.

Complications of osteosynthesis

Avascular osteonecrosis (death of bone tissue of the head).

Like fracture nonunion, osteonecrosis is associated with the degree of initial injury and the degree of displacement of fragments. Osteonecrosis is observed in 11-19% of cases with displaced fractures. That is why, in case of displaced fractures, repositioning of the fracture should be performed as soon as possible, carefully, and completed with reliable fixation of the fragments, especially in young patients.

Failure of osteosynthesis

Failure of osteosynthesis (fixation of fragments using metal structures) can be caused by the following reasons: (1) infection in the fracture area (2) loss of fixation, (3) nonunion of the fracture, (4) osteonecrosis. If the fracture does not heal despite osteosynthesis, then eruption of metal structures or the so-called cut-off process usually occurs. If the operation is performed correctly and the rules of conduct in the postoperative period are observed, the likelihood of this complication is minimized.

Infectious complications after osteosynthesis of femoral neck fractures usually lead to significant dysfunction of the hip joint. The incidence of this complication is less than 1%. The risk depends on many factors, mainly on concomitant diseases (diabetes mellitus), bad habits (smoking, alcohol abuse).

Fractures of the femoral neck are intra-articular, that is, the fragments are washed by synovial fluid, which is normally contained in the joints and contains substances that prevent the germination of blood vessels and complicate the healing of the fracture. Accurate alignment of fragments (fracture reduction) and reliable fixation reduce the risk of fracture nonunion to an acceptable level. The average rate of fracture nonunion is approximately 8.9%. Displaced fractures requiring open reduction are accompanied by a nonunion rate of 11.2%. If reduction can be performed closed, the rate drops to 4.7%. For non-displaced fractures, this incidence is only 0.9%.

Non-union of a fracture may be due to insufficient blood circulation in the fracture area, inaccurate comparison of fragments and failure of osteosynthesis. The latter may be associated with the use of outdated methods that do not provide stable fixation of fragments, errors in performing osteosynthesis, low bone density, which does not allow stable fixation of fragments (metal structures “cut” through the bone, just like a knife passes through a piece of wet sugar). It is clear that if the bone tissue of the head dies, fracture fusion cannot occur in principle.

It is possible to accurately establish non-union of a femoral neck fracture one year after the fracture; it can be predicted with high probability within six months.

For fracture nonunion, the following treatment methods can be used:

1) repeated osteosynthesis (reosteosynthesis), 2) subtrochanteric osteotomy - intersection of the femur below its trochanters to change its geometry and redistribute loads 3) hip replacement - total or only the head of the femur 4) arthrodesis of the hip joint - surgery to eliminate it, aimed at fusion of the femur and pelvis.

Recovery in specialized centers

Immediately after the operation, many begin to look for where to undergo rehabilitation under the supervision of specialists in order to regain all lost functions after a hip fracture. For such tasks, special centers are suitable, where they offer a complete program:

• Exercise therapy according to timing with the use of simulators;
• massage under the supervision of a doctor;
• kinesitherapy;
• selection of physiotherapy methods;
• working with a psychologist.

Additionally, you can take a voucher for sanatorium treatment. Such measures are carried out at a later date and are recommended for almost all patients.