X-ray (radiography) of the hip joint in children

Problems in the work of the osteoarticular apparatus, unfortunately, affect people of any age. The child’s body has its own peculiarities in the structure of bones, which is why the fetus during its stay in the womb, as well as at the time of birth, pathologies of bones and joints can occur and develop – they are called congenital. These pathologies include hip dysplasia. Being detected in the early stages of life, this violation of the structure of the articular apparatus can be easily corrected, and does not entail any threat to health. However, if dysplasia is not detected in the first months of life the child, and not treat it, in severe cases, it can lead to even child’s disability. One of the effective methods for diagnosing dysplasia is radiography of the hip joints in children.

Radiography of the hip joints: the essence of the method

The classic X-ray examination is based on the ability of specific R-rays to pass through solid objects of different densities with different intensities. Radiation of this type was discovered at the end of the 19th century, and after 15-20 years it began to be used in medical institutions for diagnostic purposes.

The examination of the patient takes place using a special apparatus. The patient placed in the regionprojections rays, and fix the image, as if photographing the patient. Instead of photographic film, an X-ray film treated with a chemical composition containing silver bromide is used; instead of a camera, an apparatus with an X-ray tube producing R-rays is used.

The images obtained in this way are highly accurate and informative; bone formations and joints, in particular, hip joints, are especially well and clearly visible on them.

What is dysplasia and why to diagnose its presence

Out of a hundred newborn children, three are born with TBD joint dysplasia. A feature of the infant’s musculoskeletal system is the presence of more cartilage than bone. The bones of the baby do not yet contain enough calcium, they are more flexible than those of adults. Therefore, children’s fractures are not the most common phenomenon, while dislocations and subluxations are much more common in them.

Dysplasia is a congenital disorder anatomical structure and development of the hip joint. Pathology can cause a violation of its mobility and chronic hip dislocation. Accurate information about what exactly becomes the cause of its occurrence, doctors not yet. It is believed that the violation is formed in the fetus at 2-3 months of pregnancy. Perhaps this is facilitated by past infectious diseases, unfavorable environmental conditions, exposure to toxins and bad habits, such as drinking alcohol or smoking.

Another theory suggests that the formation of chronic subluxation of the TGJ joint is promoted by excessive accumulation of oxytocin, a pregnancy hormone that provokes the onset of labor. It is produced in the body of the future mother by the third trimester of pregnancy, and causes an increase in muscle tone in the fetus, which is why dysplasia develops.

The emergence of such a diagnosis is especially facilitated by residence fetus in the womb mothers with crossed legs.

The risk of developing pathology increases the incorrect location of the fetus in the womb, as well as the factor of hereditary predisposition.

In some children born with TBD joint dysplasia, its reduction occurs arbitrarily immediately after birth.

In fact, dysplasia is a discrepancy between the articular surfaces. If the child lies crossedother feet, the acetabulum and the surface of the femoral head are not in direct contact during development. Even normally, the joints and bones of the fetus are not particularly stable – this is due to the need to facilitate its passage during childbirth. However, with dysplasia, the development of the ossification points of the joint occurs with a delay, and the ossification nuclei are smaller than normal. Visually, their vertical-lateral displacement relative to the normal position is clearly visible. Also, dysplasia is characterized by a slowdown in the process of ossification.

The development of dislocations and subluxations of TGB joints is also possible during childbirth, since the joint in a newborn composed from cartilage, and the degree of conformity between the shape and size of the articular surfaces (joint congruence) is low. Head size femoral the bones do not correspond to the size of the acetabulum, the ligaments are not very elastic. All this contributes to the appearance of hip dysplasia in children.

If the pathology is not detected immediately after the birth of the child, it will be more difficult to work on its correction in the future. When the child begins to walk, dysplasia is manifested by lameness; there is also a noticeable difference in the length of the legs of the baby.

When a child reaches three or four years of age, curing dysplasia becomes much more difficult. In adulthood, it is no longer possible to correct the pathology. Moreover, due to the incorrect formation of the articular apparatus, a person may experience lameness, gait disturbances, and pain. Dysplasia increases the risk of hip fracture, and contributes to faster wear of the joint, which can lead to disability.

Stages of joint dysplasia

Depending on how the articular apparatus and its parts are susceptible to pathology, the following stages of dysplasia are distinguished:

• pre-dislocation: the mildest degree, when the head of the femoral bone can move inside the acetabular cavity, and the joint itself is characterized by instability;
• subluxation: the stage when they begin formthere are anatomical and morphological changes, the head of the femur moves away from the articular cavity, but remains within the limbus (a cartilaginous plate that prevents the head from moving upward);
• dislocation: in this case, the femoral head completely leaves the joint cavity, while the limbus shifts upward, the ligaments of the joint are stretched.

In what cases is an X-ray of the TBD of the joints prescribed for children?

Responsibility for the health of the child from the first days, except for the parents, is borne by the neonatologist and pediatrician. These wizards conduct the very first examination in the life of the baby. As for the orthopedist, parents together with the child should get to him no later than a month after his birth.

However, even before visiting an orthopedist, the parents themselves or the pediatrician during the initial examination may suspect dysplasia. This is possible with a severe form of pathology, if the femoral head completely comes out of the acetabulum. If dysplasia has not affected the articular apparatus so much, only a specialist of the appropriate qualification can determine it.

Signs that should alert parents and pediatricians:

• impaired mobility of the joint, difficulty in breeding the hips, to the point that the child cries when trying to take the leg aside;
• asymmetry of the inguinal and gluteal folds: on the side where the joint is affected by dysplasia, they are more pronounced;
• shortening of the leg, if the pathology is developed in only one joint;
• snap symptom: the head of the femur pops out of the cavity of the joint with a characteristic sound when the child bends the legs at the knee and hip joints.

Diagnosis of pathology can occur directly in the hospital, while the child is there with the mother after childbirth. Dysplasia can be detected by an orthopedist during the first appointment. In any case, if any of the physicians detects signs of dysplasia in a child, it becomes necessary to visually assess the degree of damage to the joint, its structure, the shape of its components and how they touch. For these purposes, the doctor sends the baby for diagnostic tests. Survey.

X-ray of the hip joints in children is not carried out in every case. Due to the fact that the procedure involves x-ray exposure of the patient, children under the age of three to four months are not recommended to have x-rays at all. An orthopedic doctor can prescribe preventive measures without x-rays, for example:

• the use of soft tires with a spreading mechanism;
• massage of the gluteal muscles;
• course of special medical gymnastics.

In each case, the doctor decides whether to send the child for an ultrasound of the joint, or for an x-ray. Some doctors are guided by the principle “any diagnosis is better than the absence of examination and treatment.” The implementation of x-rays is advisable if the benefit from the information received exceeds the likely threat to the health of the baby from radiation exposure. Otherwise, the doctor gives the small patient a referral for an ultrasound of the joint.

Risks and dangers of x-rays of the hip joint in a child

Until the onset of puberty, it is considered that the implementation of radiography for the patient is indicated only in exceptional cases. In addition, an interval of at least 6 months must be observed between procedures. More than twice a year, the appointment of an x-ray of the hip joint in children is not recommended.

Contraindications for radiography for a baby are:

• immunodeficiency and other disorders in the immune system;
• predisposition to oncological diseases;
• metabolic disorders;
• obvious atrophy of organs or muscles;
• diagnosed pathologies of the bone apparatus.

This diagnostic method can adversely affect:

• sex cells;
• bone marrow cells;
• eye lenses;
• epithelial cells that form the mucous membranes of organs and skin;
• organs of the endocrine system.

Despite this, the method of X-ray examination of the joints in children is still used by doctors. if necessary, as it is the most effective and objective of the existing ones. It is he who allows you to determine the presence of dislocation or dysplasia with an accuracy of up to 75%.

Preparation of the child and technique of the procedure

There is no need to carry out any specific preparatory measures before taking x-rays of the hip joints. For very young patients, you need to follow the usual sleep and feeding regimen. Babies older than a year or a year and a half can clearly and in general terms explain what will happen during x-rays, tell them that the upcoming procedure is painless, and you should not be afraid of it.

The child lies on his back during the x-ray. In this case, the patient’s legs should be extended evenly, they cannot be bent. In newborn children, the legs approach the body and move slightly inward.

If the child’s pelvis is firmly pressed by the cassette to the plane of the couch or table, his movements will not interfere with the fixation of the picture. The genitals are covered with a protective lead apron to prevent exposure to x-ray exposure.

If there are no contraindications to the use of anesthesia, the procedure can be performed by entering small patient under general anesthesia to ensure the accuracy and quality of the images.

The process of deciphering the results of the survey

After the doctor-radiologist receives x-ray images, he needs to interpret them and draw up a conclusion.

To decipher the results, there is a special technique called the Hilgenreiner scheme. It includes the following categories:

• acetabular angle;
• the Hilgenreiner line;
• the distance between the metaphyseal plates and the Hilgenreiner line, denoted by the letter h;
• the distance from h to the lower contours of the vestibular plate, denoted as d.

The acetabular angle is defined as the area between two planes – the line of epsilon cartilage and the tangent passing through along edges of the articular cavities.

The Hilgenreiner line is drawn horizontally through the Y-shaped cartilages along the lower points of the ilium.

The distance h is measured from the Hilgenreiner line to the middle of the metaphyseal plate of the proximal femoral bone. It can be used to track how much the head of the femoral bone is displaced in relation to the joint cavity.

Gap d shows the lateral displacement of the head compared to the acetabulum.

The scheme makes it possible to represent the joint in a three-dimensional projection. Even at the earliest stages, it makes it possible to detect most pathologies and developmental disorders of the joint.

For greater reliability, the scheme provides for additional indicators – the Calve and Shenton lines. The first of them connects the upper edge of the femoral neck with the outer edge of the ilium, and normally it should be continuous. If the line is interrupted, this may indicate a lack of integrity of the articular apparatus.

Shenton’s line is a continuation of the circumference of the acetabulum, in the form of a projection on the medial surface of the femoral neck. Its rupture means lateral-proximal displacement of the femur.

There are also auxiliary schemes for deciphering the radiograph of the TBD joint in children – the Reinberg scheme and the Ombredan scheme.

How the radiograph of the hip joint of a child is deciphered according to the Reinberg scheme

This imaging technique uses the median sacral line, a horizontal line passing through the tops of the Y-shaped cartilages and the centers of the ossification nuclei in the heads of the femur (line A), and a vertical line drawn through the upper-lateral prominence of the acetabulum (line B) . In addition, the determination of the normal state of the joint is associated with the location of the lower edge of the femoral neck – with the normal development of the joint, it crosses the lower contour of the inguinal bone.

Between the line B and the median sacral, an auxiliary line B1 is drawn, the length of which helps to assess the condition of the joint.

Dysplasia is determined if the proximal end of the femur is above line A and, as it were, outside of plane B.

What is the Ombredan scheme

In the process of examining the results of radiography, the doctor in the picture draws a horizontal line along the synostoses connecting the pubic and ilium bones. A vertically lowered perpendicular is drawn to the outer edge of the acetabulum of the joint. With this perpendicular, the articular cavity is divided into equal segments, in relation to which the compliance of the anatomy of the joint with normal indicators is assessed.

Norm and deviations in the picture of the hip joints

The resulting image of the joint, if it is in a normal state, visualizes the head femoral  bone located in the articular cavity, which has the form of a notch. In the center, the head is attached to the surface of the cavity by a round ligament and a joint capsule. From above, the head is held in a normal position with the help of a limbus – a cartilaginous plate. The entire articular apparatus is supported externally by the muscular corset of the thigh.

Dysplasia in the picture is characterized by a delay in the development of ossification. The ossification nuclei are small compared to the norm. Dislocation or subluxation can be detected by the lateral and vertical displacement of these nuclei, thanks to the use of the Ombredan, Reinberg, Hilgenreiner schemes.

Complementary and alternative ways of examining the state of the joints

In general, radiography of the hip joint in children provides enough information to determine the presence of dysplasia and the degree of its development. However, if the procedure was not so effective, necessary for an accurate diagnosis, the doctor prescribes a CT scan of the joint. This technique is also associated with the use of X-ray irradiation, but the dose of radiation exposure to the body from it is much less than from radiography. CT makes it possible to examine the deep structures of the articular apparatus, as well as the state of the articular surfaces. All bony structures appear more contrasted and saturated than on x-ray, but the difficulty is that the border of normal cartilage can be confused with the expansion of the joint space.

Even if the results of CT do not allow the doctor to objectively assess the condition of the joint and the degree of damage, arthrography may be prescribed – an x-ray of the joint with a contrast agent. Arthrography images visualize all parts of the joint apparatus, including the articular surfaces and their structure, as well as the joint space.

Ultrasound is still considered the most gentle way to diagnose a joint condition – a harmless and painless method that uses the properties of ultrasonic waves to display a picture of the state of internal organs, muscles, tissues, joints. During the first month of life, children are advised to have an ultrasound of the hip joints as preventive diagnostics. However, in terms of information content, ultrasound is to a certain extent inferior to x-rays.

The normal anatomy of the hip joints implies that the heads of the femur are related in size to the diameter of the articular cavity, have good mobility, and are sufficiently fixed in acetabular cavity with the help of ligaments, limbus and capsule, and when the limb moves in the joint, there are no extraneous sounds, for example, clicks, crunch.

Congenital abnormalities in the development of the joint are provoked by many factors, although there is no scientific justification for the objective causes of the appearance of dysplasia today.

Dysplasia is a mismatch in size and a violation of the congruence of the articular surfaces, a dislocation or subluxation of the femur, in which its head does not fit correctly into the acetabulum. Pathology not only impairs the mobility of the joint – if it is not detected in infancy, progressing into adulthood, it accelerates the wear and tear of the joint, and can cause disability.

In order to prevent such a development of events, you need to carefully monitor the presence of signs in the child that indicate a violation of the joint. Usually, an ultrasound scan is prescribed for newborns, but in difficult cases, doctors talk about the need to make an x-ray of the child’s hip joint. The method of examination makes it possible to diagnose dysplasia with a probability of up to 75%. Based on the available images, the doctor determines the level of development of articular dysplasia, and also develops treatment tactics.