X-rays are often done in children to identify hip dysplasia. According to statistics, this common disease occurs in every seventh child. Moreover, 80% of cases occur in girls. Dysplasia that is not treated before one year of age ultimately leads to disability. Detection of pathology before the age of 1 month of life leads to complete cure of the disease. However, the ability to recognize the disease in newborns is limited and requires the experience of a doctor. Therefore, hardware diagnostics is crucial for the outcome of the disease.
Congenital hip dislocation is an extreme degree of hip dysplasia
In Russia, an X-ray of the hip joint is a mandatory method for confirming or excluding the disease. Let's find out at what age children get joint x-rays. What can be seen in the picture in normal conditions and in cases of dysplasia. What alternative examination methods exist. Let's look into all these issues.
Causes
Confirmation of a violation of the primary anlage is evidenced by cases of combination of hip dysplasia with other congenital defects.
As for the second point of view, its supporters consider the cause to be the unfavorable influence of exo- and endogenous factors on the fetus.
This is confirmed by the study of the external environment in industrially polluted areas, where the percentage of dysplasia is much higher.
So, these two theories provide the basis for uncovering the etiology of congenital hip dysplasia.
Typical for hip dysplasia is hypoplasia of the acetabulum: it is small, flat, elongated in length, with varying degrees of increase in the bevel of the arch (beyond 30°).
As a rule, with hip dysplasia, the ossification nuclei of the femoral head appear late and its development is delayed.
The physiological torsion of the proximal end of the femur is disrupted: excessive (more than 10°) rotation (deviation) of the head and neck of the femur occurs anteriorly - antetorsion or, less commonly, backward retroversion with an increase in the neck-shaft angle.
With congenital dysplasia of the hip joint, there is always dysplasia of the muscles, capsule and ligaments.
A feature of dysplasia, in contrast to subluxation or dislocation of the hip, is that the head is always centered in the acetabulum.
At the present stage of medicine, obstetricians, midwives, and visiting nurses must undergo appropriate training in diagnosing congenital defects, especially dysplasia, congenital hip dislocation, torticollis and flat feet.
Symptoms
When testing passive movements in the hip joint, the doctor bends the legs in the hip and knee joints to a right angle, and then slowly begins to spread them and feels that abduction on one side becomes limited (for unilateral dysplasia) or notes that abduction of both hips is limited (for bilateral dysplasia ).
Thus, hip dysplasia is characterized by three symptoms:
- the presence of additional folds on the medial surface of the upper third of the thigh;
- asymmetry of folds;
- limitation of hip abduction.
These are not pathogmonic symptoms, not absolute, but relative, indicating the presence of disorders in the hip joint, although they also occur in healthy children.
X-ray control
X-ray monitoring, which is carried out after three months of age, after the appearance of ossification nuclei of the epiphysis of the femoral head, makes it possible to clarify the diagnosis. The data obtained are assessed according to the Hilgenreiner scheme.
The following radiological symptoms are characteristic of congenital dysplasia: sloping roof of the acetabular fossa, flat, shallow acetabular fossa; late appearance of ossification nuclei of the epiphyses of the head; the head is centered without lateroposition.
Hilgenreiner scheme
On an x-ray of the pelvis and hip joints, a horizontal line is drawn through the V-shaped cartilages (Kaper's line).
The second line - a tangent line - is drawn from the upper edge of the roof of the acetabulum parallel to the latter and connected to the Köhler line. An angle is formed, which should normally be no more than 30°.
Next, along the horizontal Köhler line, segment d is laid from the center of the bottom of the acetabulum to the inner edge of the ossification nucleus. Normally, this segment is 1–1.5 cm.
An increase in the length of the segment indicates the presence of a lateroposition of the head. The next line is drawn from the top point of the roof in the form of a perpendicular to the Köhler line and continues to the thigh.
This perpendicular divides the acetabulum into 4 sectors. The ossification nucleus of the femoral head should always be in the lower internal sector.
In addition, a perpendicular is drawn from the Köhler line to the ossification nucleus of the femur. The length of this perpendicular is normally 1.5 cm. This indicator indicates the absence of upward (proximal) displacement of the head.
In addition, the absence of intra-articular displacement of the proximal end of the femur is indicated by Shenton’s line, which runs along the internal contour of the femoral neck and smoothly, without rupture, passes to the superomedial contour of the obturator foramen.
Treatment
In addition, parents are taught to perform hip abduction exercises before swaddling. After 3 months of life, they must undergo X-ray control, make sure that there is dysplasia, and put on Pavlik stirrups .
Their advantage is that they provide free access for the child’s hygiene, allow active movements of the legs with the hip and knee joints fixed at a 90° angle with the gradual achievement of full abduction of the hips.
Depending on the degree of dysplasia, Pavlik stirrups are worn for 3–6 months. The criterion for removing the stirrups is the complete restoration of the roof of the acetabulum, the angle of which in the Hilgenreiner diagram should be no more than 30°.
Why is hip abduction therapeutic?
Firstly , when the hip is abducted at an angle of 90°, the head is centered and constant pressure on the roof of the acetabulum is eliminated, which allows the elements of the hip joint to form correctly.
Secondly , constant irritation of the joint capsule and muscle functioning during active movements improves microcirculation, which also has a positive effect on the process of further development of the acetabulum.
Contraindications for X-rays in children
According to the schedule, ultrasound of the hip joints is performed at 1 and 4 months
According to Russian medical standards, radiography is allowed for children from 3 months of age. During the newborn period, safe and accurate diagnosis can be made using ultrasound. In exceptional cases, x-rays are allowed at any age.
X-ray examination is not carried out in early childhood for many reasons:
- radiation exposure negatively affects the hematopoietic system and the development of nerve cells;
- Some older models of X-ray equipment are manufactured with a standard power that does not allow the radiation dose to be adjusted for children.
X-rays are contraindicated in children suffering from immunodeficiency due to bone marrow suppression. X-rays are contraindicated in a child suffering from juvenile idiopathic osteoporosis. For other categories of patients, if dysplasia is suspected, x-rays are a mandatory standard examination method.
Symptoms of congenital hip dysplasia
The most likely signs of congenital dysplasia of the hip joints in children of the first year of life are: external rotation and shortening of the lower extremities, asymmetry of the folds on the thigh, buttocks and in the popliteal region, a symptom of greater trochanter protrusion, a symptom of asymmetrical abduction of the hips, a symptom of excessive ablation of the hips, an increase in the volume of rotational movements, a symptom of slipping, a symptom of a non-disappearing pulse. As the child grows, a gait disorder is noted; if the hip is dislocated, lameness, body swaying, “duck gait,” and a positive Duchenne-Trendelenburg sign are noted.
The Hilgenreiner scheme, Ombredan and Shenton lines are of great help in diagnosing congenital pathology of the hip joints in children of the first year of life.
In 1925, H. Hilgenreiner determined the distance from the lateral protrusion of the femoral neck to the horizontal line connecting both Y-shaped cartilages (h), which is normally 10 mm (Fig. 24). The distance between the medial prominence of the femoral neck and the ischium (d) is normally 5 mm. The angle formed by the horizontal line connecting both Y-shaped cartilages and the line running along the edge of the cavity (acetabulum angle and acetabular index) is normally 25 o in children of the first year of life.
How are hip x-rays done in young children?
X-rays of the hip joint are done in infants in a supine position. In this case, the child’s legs are straightened and stretched lengthwise. It is unacceptable for them to be bent at the knees or hip joints.
X-rays of newborn children differ in that the legs are brought toward the body and slightly shifted inward.
When the pelvis is tightly pressed to the cassette, the baby’s movements do not interfere with filming. The genital area is covered with a lead apron to prevent reproductive dysfunction. To ensure the quality of the image, ideally the baby should be put to sleep before the session.
X-ray morphometry
It consists of drawing a horizontal line through both Y-shaped cartilages, then from the highest point of the femoral diaphysis, drawing a line perpendicularly until it intersects with the horizontal line. Normally, the length of this perpendicular (h) is 1-1.5 cm. The distance from the bottom of the acetabulum to the perpendicular (D) is normally also 1-1.5 cm. With dislocation, the distance (h) decreases and (D) increases. A tangent line is drawn from the bottom of the acetabulum to the most peripheral part of the roof of the acetabulum. The resulting angle (a) (acetabular index) usually does not exceed 30°, but in children under 3 months it is very variable (12°-38°). Therefore, this scheme is most suitable for assessing the condition of the hip joint in children older than 3 months.
A line (B) is drawn through the superolateral protrusion of the acetabulum parallel to a line drawn through the middle of the sacral vertebrae. Thus, the joint is divided into four quadrants. With dislocations and dysplasia, the center of ossification is determined in the outer quadrants. In children in the first days of life, the ossification point of the femoral head is absent, therefore, with dysplasia, a displacement of the proximal metaepiphysis outward from the vertical Ombredan-Perkins line is noted. This scheme is convenient for identifying dysplasia in children in the first days of life, especially since it is little affected by errors (small distortions) in placement.
Alternative screening for dysplasia
Ultrasound of the hip joints can detect all stages of dysplasia
A gentle method for diagnosing the hip joint in children is ultrasound. Ultrasound screening diagnostics of all newborns in the maternity hospital to detect dysplasia is being actively implemented throughout the world. Since 1992 it began to spread in Europe, and since 2007 it has been carried out in Russia. If screening diagnostics were not carried out in the maternity hospital, it is recommended to do this at the age of 1 month of life to identify dysplasia. The need for ultrasound at this age is dictated by risk factors - breech presentation of the child or previous illnesses of the mother.
To summarize the topic, let us recall that to identify the common disease dysplasia, an X-ray of the hip joint is taken. According to Russian standards in medicine, X-rays can be done at 3 months of age. However, early diagnosis before 1 month of age is important for the outcome of the disease. Therefore, if there are existing risk factors, it is recommended that newborns undergo an ultrasound of the joint. In other situations, children from the age of three months are given x-rays to detect dysplasia.