How to determine hip dysplasia in a child?

Definition

Hip dysplasia describes a spectrum of different pathologies in newborns and young children. This includes abnormal development of the acetabulum and proximal femur, as well as mechanical instability of the hip joint. As information accumulated, terminology changed. Initially, they often talked about congenital dislocation of the hip, but the pathology is not always identified at birth, developing in early childhood, so the definition of “congenital” was abandoned. It further became clear that the manifestation of pathology can be not only a dislocation, but also a number of other conditions, so that as a result, the modern term “dysplasia of the hip (or hip) joints” was formed.

Epidemiology

Estimates of the incidence of hip dysplasia are quite variable and depend on the means of detection, the age of the child, and diagnostic criteria.
It is estimated that dislocated hips or hips with severe or persistent dysplasia occur in 3 to 5 children per 1000. Historically, the incidence of hip dysplasia with dislocation is 1 to 2 per 1000 children. Mild hip instability is more common in newborns, with a reported incidence of up to 40%. However, mild instability and/or mild dysplasia during the neonatal period often goes away on their own, without the intervention of specialists. Infants with mild instability and/or mild dysplasia during the neonatal period, according to modern concepts, should not be included in the assessment of overall morbidity, otherwise a distortion occurs that significantly overestimates the overall assessment of the prevalence of pathology. In a prospective study published in Pediatrics, 9,030 infants (18,060 hips) were routinely screened for joint dysplasia by physical examination and ultrasound during the first to third days of life. Ultrasound abnormalities were found in 995 joints, with an incidence of 5.5%. However, when re-examined between two and six weeks of age without previous treatment, residual abnormalities were found in only 90 hips, which ultimately corresponds to a true incidence of dysplasia of 0.5%. It was these children who required further treatment. In other words, 90% of newborns with clinical or ultrasound signs of hip dysplasia improved spontaneously between two and six weeks of age to the point that they did not require medical intervention.

The incidence of hip dysplasia depends to some extent on ethnic factors. It is maximum among the Sami and American Indians (from 25 to 50 cases per 1000 births), and minimum in populations of African and Asian origin.

Both joints are affected in 37% of patients. Among unilateral cases, the left hip joint is more often affected than the right. The predominance of left-sided cases may be due to the typical position of the fetus in the uterus, in which the left thigh is pressed against the mother's sacrum.

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Etiology and pathogenesis

The development of the hip joint depends on normal contact between the acetabulum and the femoral head, promoting mutual induction.
Abnormal development may result from disruption of this communication as a result of a variety of genetic and environmental factors, both intrauterine and postnatal. By the 11th week of pregnancy, the hip joint is usually fully formed. The head of the femur is spherical and set deeply in the acetabulum. However, it grows faster than the socket, so that by the end of pregnancy the head of the femur is covered by less than 50% of the roof of the acetabulum. During the last four weeks of pregnancy, the femur is vulnerable to mechanical forces, such as adduction, that force the femoral head away from the central part of the acetabulum. Conditions that limit fetal mobility, including breech presentation, enhance these mechanical factors. All this leads to eccentric contact between the femoral head and the acetabulum. During the newborn period, ligamentous laxity makes the developing hip susceptible to other external mechanical forces. A fixed position with the hips extended, such as tight swaddling, can result in eccentric contact of the hip joint as the femoral head slides in or out of the acetabulum. If these factors persist, abnormal hip joint contact results in structural anatomical changes. If the head of the femur is not seated deeply into the acetabulum, the labrum may evert out and flatten, and the round ligament may elongate. Abnormal ossification of the acetabulum occurs and a shallow version develops.

Over time, hypertrophy of intra-articular structures occurs, including the labrum with a thickened ridge (neolimbus), round ligament, and fibrofatty tissue (pulvinar). Contractures develop in the iliopsoas and hip adductors, and the inferior capsule is retracted into the empty acetabulum, further reducing the likelihood of transition of the femoral head into the acetabulum. A false acetabulum can form where the head of the femur meets the side wall of the pelvis above the true acetabulum. Lack of contact between the head of the femur and the acetabulum inhibits further normal development of the hip joint. With or without complete hip dislocation, dysplastic changes may develop. The most common result is a shallow acetabulum with reduced anterior and lateral coverage of the femoral head. Asphericity of the femoral head, valgus angle of the neck and shaft, and persistence of excessive femoral anteversion may also be observed.

Risk factors

Dysplasia is more common among infants with certain risk factors (eg, female gender, breech presentation in the third trimester, family history, tight swaddling of the lower extremities).
However, with the exception of females, most infants with a confirmed diagnosis of hip dysplasia do not have any special risk factors that could be realized. Female.

The risk of dysplasia in girls is estimated at 1.9%. Hip dysplasia occurs two to three times more often in them than in boys. In a 2011 meta-analysis published in the European Journal of Radiology, which evaluated 24 studies and more than 556,000 patients, the relative risk of dysplasia for girls was 2.5 compared to boys.

The increase in incidence in girls is associated with a temporary increase in ligamentous laxity associated with increased sensitivity of female infants to the maternal hormone relaxin. However, some studies refute this hypothesis.

The increased incidence of dysplasia in girls is difficult to separate from the increased risk of this condition in breech presentation, which is also significantly more common in girls.

Presentation.

Breech and breech presentation during the third trimester are the most significant single risk factors for hip dysplasia in children. The absolute risk of dysplasia is estimated at 12% in breech girls and 2.6% in breech boys. In the already mentioned meta-analysis of risk factors, 15 studies (more than 359,300 patients) on breech presentation were reviewed, and the relative risk for breech presentation was 3.8. It is unclear in the literature whether the amount of time spent in the breech position or the point in the pregnancy timeline at which the fetus was breech affects the risk of dysplasia.

An increased risk of dysplasia is present regardless of the mode of delivery. However, reducing the time spent in the breech position through elective cesarean section may reduce the risk of clinically significant hip dysplasia. This was illustrated in a 2021 retrospective review published in the journal Paediatrics & Child Health, which found a reduction in the incidence of dysplasia among breech babies who were born by elective caesarean section (3.7% compared to 6.6% among babies born by caesarean section during childbirth, and 8.1% among children born vaginally).

Family history.

Genetic factors appear to play a role in the development of hip dysplasia in children. The absolute risk in infants with a positive family history is approximately 1 to 4%. In the aforementioned 2011 meta-analysis in the European Journal of Radiology, the authors examined four studies (more than 14,000 patients) on the topic and determined that the relative risk of a positive family history was 1.39. If one twin has dysplasia, the other twin has a higher risk of having dysplasia if they are monozygotic than if they are dizygotic (40% versus 3%).

Family members of children with dysplasia are also at increased risk of hidden acetabular dysplasia, which often develops before age 30.

Swaddling.

The incidence of hip dysplasia increases in populations that use diapers and cradleboards. These practices limit hip mobility and lock the hip into adduction and extension, which may play a role in the development of dysplasia. In a pilot study in rats, traditional swaddling during hip adduction and extension resulted in a higher incidence of dislocation and dysplasia than no swaddling.

The American Academy of Pediatrics (AAP), the Pediatric Orthopedic Society of North America (POSNA), and the International Hip Dysplasia Institute (IHDI) recommend “healthy hip swaddling,” also known as “loose swaddling,” that allows ample room for hip and knee flexion and free leg movement. Other factors. Several other factors associated with decreased range of motion or abnormal positioning have been found to be correlated with pediatric hip dysplasia, but a cause-and-effect relationship has not been proven. These include torticollis, plagiocephaly, adducted metatarsus, clubfoot, first labor, oligohydramnios, birth weight >4 kg, and multiple pregnancies.

Reasons for the formation of pathology

• hereditary predisposition;
• the influence of the hormonal background of the expectant mother on the fetus during pregnancy;
• small amount of amniotic fluid;
• breech presentation of the fetus;
• disruption of the process of tissue formation in the fetus;
• high fetal weight;
• some gynecological pathologies in the expectant mother, which limit the range of movements of the fetus in the womb;
• very small weight of the newborn (up to 2.5 kg). Source: M.S. Kamenskikh, V.D. Sharpar, N.S. Strelkov, A.V. Islentiev Comprehensive assessment of risk factors contributing to the development of hip dysplasia // Genius of Orthopedics, 2012, No. 4, pp. 58-61

Let's consider the three most important reasons of all listed.

Hereditary predisposition

If parents had dysplasia in childhood, then there is a 25% chance that their child will also have this pathology.

Disturbed process of tissue formation in the fetus

Already in the sixth week of pregnancy, the fetus has a kind of “bud” of the hip joint. Movements in it become possible by the tenth week. Therefore, it is extremely important that a pregnant woman at these stages avoids all harmful factors that could disrupt the process of proper development of the unborn child:

• radioactive exposure of any intensity;
• exposure to chemicals on the body, including some aggressive drugs;
• viral diseases in the first trimester of pregnancy (this is the most important factor!);
• bad ecology.

The effect of hormonal imbalance of the expectant mother on the fetus

If a pregnant woman has a high level of progesterone in her body, which is necessary for a problem-free birth (it relaxes ligaments, cartilage, joints), then this hormone enters the blood of the fetus, as it easily penetrates the placenta. Thus, softening and relaxation of the ligamentous apparatus will also occur in the unborn baby. The negative effect of progesterone is especially strong if the birth takes place in a breech presentation or the fetus is in an incorrect position during pregnancy.

Clinical stages

Dysplasia in children, depending on the severity of the process, can be divided into the following stages:
Dysplasia.

Violation of the shape of the hip joint, usually a shallow acetabulum, in which the upper and anterior edges are affected by the pathological process.
Reductive stage.
The hip is dislocated at rest, but the femoral head can be placed into the acetabulum through manipulation, usually flexion and abduction.
Subluxation.
The femoral head is in place at rest, but may be partially dislocated or subluxated on examination.
A joint with mild instability. Replaceable option.
The head of the femur is within the socket at rest, but easily extends beyond its limits not only during examination, but also simply when changing position.
Joint with instability. Subluxation.
The head of the femur partially extends beyond the acetabulum at rest, but always remains in contact with it.
Dislocation
. Complete loss of contact between the femoral head and acetabulum.

Symptoms and signs

Hip pathology does not cause pain in infants, so it is difficult to identify.

Parents may notice:

• The baby's hip makes popping or clicking noises that can be heard.
• In infants, you may notice that one leg is longer than the other.
• One hip or leg does not move the same way.
• The skin folds under the buttocks or on the thighs do not match.
• The child has a limp when he begins to walk.

  
  Coxa Valga in children

If you experience any of these signs, you should consult a doctor. In rare cases, the pathology causes pain or discomfort. The disease often goes undetected, and in most cases Coxa Valga does not cause any symptoms when it is affected bilaterally. But with a one-sided deformity, a waddling gait develops, a nagging pain occurs in the hip area, and gait is disturbed.

Classification according to ICD-10

ICD codes for pediatric hip dysplasia should be looked for in class Q65, congenital hip deformities. These include the following options: Q65.0. Congenital dislocation of the hip, unilateral Q65.1. Congenital dislocation of the hip, bilateral Q65.2. Congenital dislocation of the hip, unspecified Q65.3. Congenital subluxation of the hip, unilateral Q65.4. Congenital subluxation of the hip, bilateral Q65.5. Congenital subluxation of the hip, unspecified Q65.6. Unstable hip

• Predisposition to hip dislocation
• Predisposition to hip subluxation

Q65.8. Other congenital hip deformities

• Anterior displacement of the femoral neck
• Congenital acetabular dysplasia
• Congenital:

√ valgus position √ varus position
Q65.9. Congenital deformity of the hip, unspecified

Diagnostics

General inspection.
To make a diagnosis, a neurological examination and examination of the spine and legs are important, during which they look for associated hip dysplasia and other causes of hip instability.

• Neurological examination should include assessment of spontaneous movements of all four limbs and assessment of spasticity.
• The spine examination should include range of motion (looking for torticollis) and cutaneous findings of spinal dysraphism.
• Examination of the extremities should include examination of the foot for the presence of the metatarsal muscle.

Mobility assessment. Results vary by age:

• In infants less than three months of age, it is important to assess hip joint stability using the Ortolani maneuver. The Barlow maneuver, Galeazzi test, and Klisic test may also be helpful. There are usually no restrictions on joint abduction at this age.
• In children older than three months, an obvious discrepancy in leg length may be noticed (for unilateral cases). The Galeazzi tests for unilateral cases and the Klisic test may be considered better indicators of hip dysplasia than instability.
• In children who are able to walk, weakness of the hip joints on the affected side can be recognized by a positive Tredelenburg test (inability to maintain a horizontal position of the pelvis while standing on the ipsilateral leg), as well as the presence of Tredelenburg roll when walking.

Ultrasonography.
Ultrasound is the main imaging modality for assessing the morphology and stability of the hip joint when hip dysplasia is suspected. This is an important adjunct in the clinical assessment of children under 4–6 months of age. The main disadvantage of the method is that an experienced and trained diagnostician is required to accurately interpret the results. Ultrasound criteria for hip dysplasia have been established for both static and dynamic imaging of the flexed hip with and without a modified Barlow stress maneuver.

Radiography.

May be useful in diagnosing hip dysplasia in children 4–6 months of age. In younger infants, it is not very informative, since the head of the femur and the acetabulum have not yet ossified and therefore do not contrast in the photographs.

Other imaging methods. Computed tomography (CT) and magnetic resonance imaging (MRI) are not suitable for diagnosing hip dysplasia in children, but can be used to assess the quality of reduction after surgery. In this case, special pediatric protocols should be used for CT scanning, providing for a reduction in radiation exposure during the study.

Differential diagnosis.

The main pathology from which hip dysplasia in children should be distinguished is also accompanied by shortening of the limb:

• Proximal focal femoral deficiency, a rare congenital disorder that ranges from hypoplasia of the femoral head to absence of all but the distal femoral epiphysis.
• Coxa vara, defined by an angle of less than 120° between the femoral neck and diaphysis, resulting in elevation of the greater trochanter.
• Hemihypertrophy or hemihyperplasia (eg, Beckwith-Wiedemann syndrome).
• Sacral agenesis with limb deformity.

Pathology of the hip joints in children

Congenital hip dislocation is the most common congenital deformity of the musculoskeletal system. This malformation extends to all elements of the hip joint: the acetabulum, the head of the femur with surrounding muscles, ligaments, and capsule and consists in the underdevelopment of these tissues.

PATHOLOGY OF THE HIP JOINTS

Congenital hip dislocation is the most common congenital deformity of the musculoskeletal system. This malformation extends to all elements of the hip joint: the acetabulum, the head of the femur with surrounding muscles, ligaments, and capsule and consists in the underdevelopment of these tissues. Emerging congenital hip dislocation occurs in 5 per 1000 children. The incidence of congenital hip dislocation varies in different countries, as it depends on climatic conditions and national customs. Thus, in Georgia in some areas it reaches 9% per 1000 children due to the traditional tight swaddling of babies and is not found at all among the black population of Africa, in Korea, Vietnam and generally throughout the entire Indochina Peninsula, where, due to the hot climate, children are not swaddled tightly .

Unilateral dislocation is more common than bilateral dislocation. Moreover, according to various authors, the frequency of bilateral dislocation ranges from 20 to 50%. With unilateral dislocation, the left side is 1.5-2 times more common than the right side. In girls, congenital hip dislocation occurs 5 times more often than in boys.

Etiology and pathogenesis

There are a large number of different theories regarding the causes of hip dysplasia. Many of them are of historical interest and cannot explain the entire complex pathological process.

The etiological factors leading to deviations in the normal development of the hip joint and surrounding muscles are called the defect of their primary formation. Some authors see confirmation of this theory in the combination of congenital hip dislocation with other congenital deformities. Other authors consider the cause of congenital hip dislocation to be a delay in the development of the normal hip joint during the intrauterine life of the fetus. These developmental disorders are sometimes explained by fluctuations in vitamin balance, hormonal disorders and other reasons.

Depending on the period of antenatal life, the femoral head and acetabulum begin to develop without close contact with each other, and varying degrees of impairment appear. This assumption does not exclude a true malformation of the acetabulum and head, when a formed dislocation is detected already from the first days of the postnatal period. The extremely rare occurrence of such an anomaly corresponds to the rarity of detecting a true, formed dislocation in newborns.

Studies conducted jointly with the All-Union Institute of Obstetrics and Gynecology (M.V. Volkov, R.L. Gorbunova, I.P. Elizarova, 1966) showed that when examining mothers, most of them had either cardiovascular diseases (rheumatic heart disease), or toxicosis of pregnancy and nephropathy, accompanied by impaired protein and salt metabolism in both the mother and the fetus.

In 50% of all those examined, there was a breech presentation of the fetus. The relative predominance of breech presentation in cases of congenital dislocation of the hip joints makes it necessary to more carefully examine the development of the musculoskeletal system in children with this type of presentation.

The mechanism of the birth act and the nature of the obstetric aid (Tsovyanov's method and the classic manual aid) do not influence the occurrence of congenital joint pathology, since it was observed in 25 children born by cesarean section, subject to all the rules for fetal extraction. In addition, dislocation is also observed with cephalic presentation.

The pathogenesis of congenital hip dislocation is associated with previous pre-dislocation of the joint, characterized by hypoplasia of the acetabulum, its flattening, small size of the femoral head and its delayed ossification, anterior rotation of the upper end of the femur (antetorsion), anomalies in the development of the neuromuscular apparatus of the hip joint area. These changes are confirmed by pathological data: the femoral head in the first months of a child’s life is displaced outward and slightly upward. Gradually, with age, the upward and posterior displacement along the ilium increases, which is accompanied by stretching of the joint capsule. Displacement of the femoral head may be slight with subluxations and more pronounced with dislocations. Changes are observed in the shape and structure of the flattened cavity, reduced head and articular cartilage, articular capsule, ligaments and muscles.

The acetabulum is usually not only flattened, but also elongated, its superoposterior edge is underdeveloped, as a result of which the roof is sloping and there is no bone support for the femoral head on top. The flattening of the acetabulum increases due to the thickening of the cartilaginous layer of the bottom of the acetabulum and the development of connective tissue at the bottom. In older children, with the formation of a dislocation, these changes increase: the upper arch may completely disappear, the cavity takes on a triangular shape and becomes flatter; the femoral neck, which develops in the absence of support, is shortened, its neck-diaphyseal angle remains obtuse (135° instead of the normal 125°); the neck, deprived of support, rotates anteriorly.

The femoral head is smaller, deformed, and appears later. In 25-30% of children, according to F.R. Bogdanov and N.A. Timofeeva, there is a macroscopic change in the cartilage of the femoral head. When the leg is loaded with a dislocated hip, the roof of the acetabulum is even more flattened. Due to the upward sliding of the femoral head, a gliding groove is formed. The articular capsule undergoes dramatic changes; it stretches, following the head moving upward and backward, sometimes the head is soldered to the bag. The joint cavity is divided into three parts and has an hourglass shape. One part - the upper - surrounds the head, the second - a flattened cavity and remains unfilled; connective tissue develops in it. Between them there is a narrowed isthmus of the bursa, which prevents the head from moving from the upper to the lower section. The round ligament is either well or poorly expressed; after 3 years of age, in half of the cases it is absent.

Diagnostics and clinic

The outcome of the disease depends on the time when the diagnosis is made and treatment is started. It gets exponentially worse every month if no treatment is given. The diagnosis of congenital hip dislocation should be made in a maternity hospital. To do this, all children should be examined by the pediatrician of the children's room of the maternity hospital, and if in doubt, by an orthopedic consultant. In the first 3-4 weeks of life, and then again at the age of 3 months, an orthopedist examines all infants in a pediatric consultation.

The importance of diagnosing hip dysplasia in the first weeks of a child’s life is enormous, but recognition is often difficult and requires special experience and knowledge.

It is no coincidence that in recent years in Czechoslovakia, all children under 3 months of age have had an X-ray of their hip joints taken, so as not to miss the difficult-to-diagnose case of dysplasia in the hip joint.

Diagnosis of dysplasia in the first months of life

The group of hip dysplasias in young children includes diseases such as: congenital subluxation, congenital subluxation, congenital dislocation and radiologically immature hip joint.

In recent years, significant progress has been made in the early detection and early treatment of congenital dysplasia in children. A good basis for early diagnosis of diseases is a well-established relationship between orthopedists and obstetricians and pediatricians in maternity hospitals.

The simplest organizational form of early detection of congenital hip dysplasia is a systematic examination of all children born in the maternity hospital. Despite the fact that the clinic of dysplasia in the first days of a child’s life is extremely poor in symptoms, it is quite sufficient for, with a certain skill, to timely diagnose or suspect this disease.

To correctly assess the results of a clinical study, examination of a newborn must be carried out using a special technique.

• The most common symptoms of congenital hip dysplasia are:
• limitation of abduction in the hip joints;
• symptom of sliding or clicking (Marx-Ortolani symptom);
• asymmetry of the folds on the thigh and the posterior gluteal folds;
• visually detectable shortening of the lower limb;
• external rotation of the lower limb.

These symptoms must be looked for and found, since they are not always clearly expressed and to clarify them, certain skills are required in examining the child.

In a child lying on his back, there is limited passive abduction of the legs, bent at right angles at the hip and knee joints. This is the earliest and most permanent sign of congenital pathology. Abduction limitation increases over time. With normal hip joints, hip abduction will be almost complete; in the presence of dislocation or underdevelopment of the hip joint, this symptom always occurs. A sharp limitation of abduction is observed with a mature dislocation and a slight limitation with other dysplasias of the hip joint.

Limitation of hip abduction is possible with spastic paralysis, muscle contracture observed in newborns and in other joints, as well as with congenital varus deformity of the femoral neck. All these diseases must be excluded by examining the condition of all muscles and using x-rays of the hip joints. It is important to note that physiological muscle rigidity in a newborn is not permanent. At certain moments, it is possible to abduct the hips, which does not happen with dysplasia before the head is reduced.

A very important, earliest, but inconsistent symptom is the clicking symptom, or the symptom of sliding, described for the first time in 1934 by the Soviet orthopedist V.O. Marx, and independently of him the Italian orthopedist Ortolani. It is also called a symptom of instability (A.P. Biezin and K.A. Krumin). The essence of the symptom is that when the legs are abducted, the dislocation is reduced, which is accompanied by a click felt by the hand of the examining doctor. Sometimes this click can be heard from a distance. When the legs are brought to the midline, the femoral head re-dislocates, also accompanied by a clicking and shuddering of the leg. To identify this symptom, there is a special technique for examining a newborn, in which the doctor, bending both legs at the hip and knee joints, places the thumbs on the inner and the other fingers on the outer surfaces of the thighs. Slowly, avoiding forced movements, the doctor moves the hips evenly in both directions.

It should be noted that the Marx-Ortolani symptom usually disappears by the 5-7th day of a child’s life, but in some children, if muscle hypotonia is present, it may persist during the first months of life.

Asymmetry of folds on the thigh or an uneven number of folds may also indicate the presence of dysplasia. There are more folds on the dysplasia side, they are deeper than on the healthy side, and are located more proximally.

This symptom is not absolute and alone, without other data, cannot be taken into account, since it is observed only in 2/3 of patients and can occur in healthy children. When viewed from behind, the gluteal folds are not at the same level. This symptom is characteristic of unilateral hip dislocation. In addition, healthy children have deep symmetrical folds between the hips and torso at the back. The asymmetry of these folds or their absence indicates the presence of unilateral or bilateral dislocation.

One of the symptoms of hip dysplasia may be external rotation of the leg on the side of the dislocation.

It is clearly visible when the child is sleeping - mothers themselves pay attention to this symptom. Visible shortening of the lower limb, characteristic of high dislocations, can be observed not only with an obvious unilateral dislocation, but also with various dysplasias, even bilateral, but with different locations of the hips in height. It is difficult to determine the length and shortening of legs in infants using a measuring tape. The difference in leg length is judged by the different locations of the levels of the knee joints, bent and close to the stomach.

All of the listed symptoms may be observed together or only part of the symptoms may occur; in the latter case, it is better to suspect a congenital pathology of the hip joint and take an x-ray. A suspected but unconfirmed hip dislocation will only indicate the attentiveness of the doctor and will not cause harm to the child. The same disease can make a child severely disabled for life.

The X-ray method of examination plays a significant role in the diagnosis of hip dysplasia in newborns. During radiography, the child lies on his back with his legs extended and adducted in a position of some inward rotation, strictly symmetrically. The pelvis should fit snugly against the cassette. It is necessary to protect the genitals with a lead plate, which, if positioned correctly, does not interfere with radiography.

When X-ray diagnosing diseases of the hip joints, it should be taken into account that newborns do not have ossification nuclei of the femoral heads, and it must be remembered that the height of the femoral head is equal to the width of the femoral neck. The acetabulum is also cartilaginous and does not provide a contrasting shadow. When reading a radiograph, particular importance is attached to the condition of the upper edge of the acetabulum, the relationship of the upper end of the femur and the acetabulum. It is also important to take into account the location of the cartilaginous head - how much higher and lateral it is than its normal position.

In the presence of congenital dislocation of the hip, an oblique position of the upper edge of the acetabulum is noted, and the upper end of the femur, including the cartilaginous head of the femur, which is supposed but not yet visible on the radiograph, is located more outward, but in some cases (even if the child is not yet standing) higher than on the healthy side. Naturally, with bilateral dislocation, X-ray diagnosis can be difficult due to the inability to make a comparison with a healthy joint.

In these cases, special schemes proposed by Ombredan, Hilgenreiner, Erlacher, Putti, S.A. are used. Reinberg and others. Such diagrams, using certain lines, establish the normal arrangement of the elements of the hip joint and, accordingly, make it possible to determine the displacement of the femur in relation to the acetabulum and determine the degree of this displacement. Early radiographic symptoms of congenital hip dislocation were first identified by the eminent Bolognese orthopedist Putti. In 1927 he proposed the classic "Putti triad":

1) increased bevel of the roof of the acetabulum;

2) displacement of the proximal end of the femur outward and upward relative to the acetabulum;

3) late appearance and hypoplasia of the ossification nucleus.

These symptoms were later supplemented by other researchers. Putti's scheme for reading radiographs is of well-known interest.

Since the ossification nucleus of the femoral head appears normally at 4-6 months of age, and in case of dysplasia - later, by 9-10 months, then in children of the first months of life, when the head, in addition, is only lateral, but not above the cavity , it is advisable to use the Hilgenreiner scheme to evaluate the radiograph. A horizontal line is drawn through both Y-shaped cartilages (Keller's line); From the highest point of the femoral diaphysis, a perpendicular h is drawn until it intersects with the horizontal line. The distance from the base of the Y-shaped cartilage to the perpendicular h is called the d value. The length of the horizontal segment d is normally equal to 1.2-1.5 cm, as well as the length of the perpendicular h. With dislocation, the value of h decreases, ad increases. From the bottom of the acetabulum, a line is drawn tangent to the most peripheral part of the roof of the acetabulum; the resulting angle (index) is normally 27-30° in a newborn and approaches 20° in a 2-year-old child. In the presence of joint dysplasia and delayed development of the acetabulum, the index increases.

Hip dysplasia is characterized not so much by an absolute increase in this angle, but by the presence of a difference in the angles on both sides, clearly indicating a malformation of the pelvis.

The scheme proposed by S.A. Reinberg, used in older children. Three vertical lines are drawn: along the midline of the body, through the superolateral edge (roof protrusion) of the healthy acetabulum and at an equal distance from the midline on the side of the dislocation. Normally, the vertical line passes through the diaphysis of the femur, and in case of dislocation, it passes more medially. A horizontal line is also drawn through the Y-shaped cartilages. Normally, the femoral head is located medial to the vertical and below the horizontal line; in case of dislocation, it is located laterally and above these lines. In children in the second half of life, attention is paid to the Shenton line. Normally, the lower contour of the femoral neck passes into the upper semicircle of the obturator foramen, but with dislocation, the arcuate line is absent, since a ledge appears due to the higher location of the lower contour of the femoral neck.

The most widely used is the Ombredant scheme, which takes into account the position of the head in relation to the horizontal line (Keller line) and the location of the femoral diaphysis (Ombredant line) in relation to the vertical line.

Thus, certain skills make it possible to give a clinical and radiological assessment of the condition of the hip joints in children in the first weeks of life.

Diagnosis and clinic of congenital hip dislocation in children older than one year

When a child begins to stand and walk, diagnosing congenital hip dislocation is less difficult.

In children after one year, one of the first symptoms that makes one think about the presence of a congenital dislocation of the hip is a late onset of walking, although this is not an absolute symptom, but is more common in the presence of bilateral dislocation, when children take their first steps at 14-15 months. The gait is characteristic: there is either some kind of instability or lameness when walking in the case of a unilateral dislocation, or a waddling, duck-like gait in the case of a bilateral dislocation. However, patients do not experience pain - the child remains cheerful and spends the whole day on his feet. Children of this age retain some of the symptoms that are important for early diagnosis, only they manifest themselves more clearly. The limb where there is a dislocation is in a position of external rotation, which is also visible during sleep. There is a relative shortening of the limb on the side of the dislocation in the absence of absolute shortening.

The relative length of the limb is measured from the anterior superior iliac spine to the medial malleolus, the absolute length is measured from the greater trochanter. The tip of the greater trochanter is located above the Roser-Nelaton line, which connects the anterior superior iliac spine to the ischial tuberosity. On the side of the dislocation, abduction of the hip is also limited, but rotational movements in the hip joint are possible to a greater extent than normal (Chassignac's symptom).

An important classic sign of a mature dislocation is a positive Trendelenburg sign. Normally, when you lean on your healthy leg, the buttock on the other side rises; in the case of congenital dislocation, when supporting the dislocated leg, the buttock of the other side drops (regardless of whether there is a dislocation on this side or not).

Trendelenburg's symptom is a reflection of the condition of the gluteal muscles of the limb on the side on which the child is standing. With normal tone of these muscles, they tense and to create balance when standing on one leg, the opposite half of the pelvis rises (a negative symptom of an elevated buttock). When standing on a leg with a congenital dislocation of the hip, as in the first case, the torso also tilts to maintain balance in the same direction, but the gluteal muscles are not able to bring their attachment points closer together (the greater trochanter - the crest and wing of the ilium), the opposite half of the pelvis sinks under the weight of the body (a positive symptom of a drooping buttock). Thus, a positive Trendelenburg sign is a sign not only of congenital hip dislocation, but also of any pathology associated with weakened tone of the gluteal muscles on the standing side. Their tone is reduced with paresis or paralysis of the muscles (consequences of poliomyelitis), with the points of attachment of these muscles approaching each other (acquired dislocations and varus deformity of the femoral neck with a high position of the greater trochanter).

When the child is positioned on his back with his legs extended, it is easy to determine Dupuytren's symptom - when pressure is applied to the heel area, the mobility of the leg along the axis and its upward displacement are determined.

One of the clinical prognostic symptoms in children over 1 year of age is the symptom of hip reduction. In a horizontal position, lying on his back, the patient is pulled with one hand by the lower third of the thigh, the pelvis is fixed with the other hand and the descent of the greater trochanter is observed. This symptom makes it possible to judge the degree of fixation of the head and joint capsule in children who have not been treated for several years and have been loading a dislocated leg, and to decide on the choice of treatment method.

With a unilateral dislocation, the normal femoral head, being in the socket, is palpable at the level of the pulsation of the femoral artery, but on the sore side the head in this place is not palpable.

The final diagnosis in children over 1 year of age is made on the basis of radiographs of the hip joints. The image not only confirms the diagnosis, but also allows you to more accurately judge the degree of dislocation and the prognosis of treatment, as it gives an idea of ​​the changes that have occurred in the head, neck, cavity and its roof.

The radiography method for this disease has not only diagnostic, but also prognostic significance. In children 2-3 years old, when the question of choosing an open or closed method of reduction is being decided, it is advisable to take a photo while standing, lying down, and also when pulling the hip down with countertraction. With a deliberately chosen surgical method of treatment, these images make it possible to understand the choice of the surgical method and the types of techniques (for example, with pelvic osteotomy, you can decide which is more appropriate: the Hiari, Salter or Degas operation; when performing hip resection, you can clarify the size, level and shape of the resected section of bone etc.). Radiographs taken simultaneously in the midposition and in internal rotation are better than other methods in determining the presence of antetorsion and the degree of anteversion - anterior rotation of the neck.

It is important to note that in children older than one year and especially in adolescents, there is a pronounced deformity of the femoral neck with anterior rotation - anteversion, therefore, on direct radiographs of the joint in the middle position of the lower extremities, when in the supine position the patella is facing upward, the femoral neck has a false appearance in the shadow of the radiograph valgus form. An image in internal rotation usually reveals a well-defined, sometimes elongated femoral neck with a normal neck-diaphyseal angle. In this position, the head approaches the cavity and from its strictly profile picture one can see defects that are not visible on a direct radiograph - its true size, flattening, depressions on the head in the middle as a result of cartilage degeneration (often bicornuate form) due to unsuccessful attempts at reduction.

The atrography of the joint undertaken by some authors with oxygen or contrast liquids has only scientific significance, as it confirms morphological changes in the stretched bursa and joint cavity.

Differential diagnosis

Congenital dislocation of the hip in infants should be differentiated only from congenital shortening of the hip or some other rare developmental anomaly (complete underdevelopment of the proximal end of the femur), as well as from physiological or spastic muscle hypertension, which disappears or is overcome after a certain period of muscle tension.

Differential diagnosis in children over one year of age is carried out with all diseases accompanied by Trendelenburg's symptom, duck-like gait or limping gait. Among these diseases, two groups can be distinguished: 1) diseases that also cause dislocation syndrome (pathological dislocations of the hip after infantile paralysis, osteomyelitis and trauma), 2) diseases accompanied by varus deformity of the femoral neck (rickets, chondrodystrophy, deformity after Perthes disease, congenital varus cervical deformity, osteomyelitis and tumors of the femoral neck, chondrodysplasia and epiphysiolysis of the femoral head of various etiologies).

Paralytic dislocation of the hip after poliomyelitis is accompanied by a characteristic history, atrophy of the gluteal and femoral muscles, and on the radiograph is distinguished by osteoporotic bones without flattening of the acetabulum. Pathological dislocation of the hip after epiphyseal osteomyelitis is observed only in infants due to the accumulation of pus, and more often reactive fluid in the hip joint. A history of high septic temperature, the presence of fistula scars, and possible destructive changes in the head are characteristic of this disease. Diagnosis of rickets in cases of bilateral congenital dislocation of the hip is most common, since rickets also causes a duck's gait in cases of developing bilateral varus deformity of the femoral neck with a positive Trendelenburg sign, limited abduction of the hips and the location of the greater trochanter above the Roser-Nelaton line. The only clinical symptom indicating the absence of dislocation is the presence of the femoral heads at the level of the pulsation of the femoral artery and, of course, the presence of other signs of rickets. X-ray examination clarifies the diagnosis.

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Treatment

In the vast majority of cases, hip dysplasia in children stabilizes on its own soon after birth and does not require any special or separate interventions.
In rare cases, gradual progression of the disease, the appearance of chronic pain and accelerated development of osteoarthritis can be observed with age. The risk of such complications is uncertain, but it may be associated with the formation of a false acetabulum. The goal of treating hip dysplasia in children is to obtain and maintain concentric contraction of the joint, that is, the alignment of the geometric centers of the femoral head and acetabulum. In young children, concentric reduction provides an optimal environment for the development of the component parts of the joint; in older children, it can prevent or delay the development of osteoarthritis of the hip joint.

The optimal environment for the development of the femoral head and acetabulum is one in which the cartilaginous surface of the femoral head is in contact with the cartilaginous floor of the acetabulum. Both the femoral head and acetabulum have the ability to grow and change shape, which can lead to gradual resolution of the dysplasia over time (months to years) if concentric contraction is maintained. The upper age limit for acetabular remodeling is estimated to be 18 months to 11 years, with maximum acetabular remodeling occurring 4 to 6 years after reduction of a dislocated hip.

0-4 weeks.

Hip dislocation is rare in babies under four weeks of age, but joint weakness (mild instability) and/or a shallow acetabulum (dysplasia) is common. Management of infants less than four weeks of age depends on clinical findings and risk factors. At the same time, retrospective studies have not shown the benefits of starting the use of fixation devices as early as possible, so such children are managed observationally, with follow-up ultrasounds performed if necessary.

4 weeks – 6 months.

The use of various fixation devices is recommended: Pavlik stirrups, Aberdeen splint, von Rosen splint for infants under six months with a dislocated hip or persistently dislocated or subluxated joints. In this case, it is better to give preference to Pavlik stirrups, which are essentially a dynamic splint that prevents hip extension and limits adduction, which can lead to dislocation, but allows flexion and abduction. This position promotes normal development of the dysplastic joint, stabilizes subluxation, and usually results in a gradual reduction in the degree of dislocation, even if the joint does not return to normal on physical examination. It is not recommended to put double or triple diapers on a child, although this approach was previously practiced. It has proven to be not only ineffective, but also potentially harmful, as it can promote hip extension, which is detrimental to the normal development of the joint.

6–18 months.

If fixation devices are unsuccessful, surgical intervention may be attempted, such as open or closed reduction under anesthesia. In children older than six months, the success rate of restoration with Pavlik stirrups is less than 50%, and there is a higher risk of osteonecrosis (avascular necrosis) of the femoral head.

Orthopedists at most centers recommend treatment for hip dislocation soon after diagnosis. The result is influenced by the age of the child and the development of the hip joint at the time of treatment. In observational studies, the earlier the intervention is performed, the higher the success rate of closed reduction; The older the patient, the greater the likelihood of requiring open reduction and possible osteotomy of the femur and pelvis.

Possible consequences and complications

If hip dysplasia is not treated or properly diagnosed at an early stage, there is a possibility of some long-term problems.

• In the future, there is a risk of premature wear of the joints.
• Teens may experience pain and discomfort in the hip, and many young people develop osteoarthritis of the hip early on. Untreated hip dysplasia is the most common cause of early onset hip arthritis in young women.
• In addition, if the femoral neck is displaced, deformity in the knees or crooked legs develops compensatoryly.
• In most cases, the pathology leads to deformation of the legs. The legs may also be shortened, which can lead to significant limitations in movement and serious complications in daily life.
• This disease significantly reduces the quality of life. The patient suffers from severe pain in the hip area. They may take the form of pain at rest or pain with pressure. The muscles in the affected areas weaken, making physical activity impossible.
• Sports activities are strictly limited. Excessive stress can later lead to a femur fracture or sprain. In most cases, treatment of Coxa valga leads to a positive course of the disease, and the symptoms are relatively well eliminated.

Deviation is often discovered by chance. In most cases, this has virtually no pathological significance. However, an excessively large femoral neck angle leads to changes in the load in the joint area. Increased pressure is placed on the sensitive articular cartilage. As a result, at this stage the articular cartilage cannot be supplied with nutrients. Older people will be more likely to develop premature osteoarthritis. Coxa valga is one of the diseases called “pre-arthrotic deformity”.

Coxa valga in children is not a disease as such, but a condition that often goes unnoticed. The intervention of a doctor is mandatory and the appointment cannot be delayed.

Forecast

Long-term treatment outcome depends on the severity of the dysplasia, age at diagnosis and treatment, and the presence of a concentrically reduced hip joint. It is generally accepted that the earlier a patient is treated, the higher the likelihood of a good outcome, which emphasizes the importance of early diagnosis. Approximately 90% of neonatal hips with instability or mild dysplasia resolve spontaneously with normal functional and radiographic results. If hip dysplasia is diagnosed before six months of age, treatment with Pavlik stirrups can achieve and maintain hip contraction in approximately 95% of patients. Long-term follow-up is important to monitor residual dysplasia, which may occur in up to 20% of patients after successful treatment. Once the hip has been stabilized and the patient has recovered from any surgical procedures, annual or biennial follow-up is recommended until skeletal maturity is achieved. Residual dysplasia after treatment or undiagnosed dysplasia may progress to osteoarthritis. Most young people who have hip replacement due to dysplasia do not have

Conclusion

Hip dysplasia in children is a common pathology, but in the vast majority of cases it resolves on its own and does not require special medical intervention. In more complex cases, it may be necessary to wear various fixation devices for several weeks - until normal formation of the joint is completed - without requiring either casting or "strict" swaddling. In isolated cases, surgery may be required, and the earlier it is performed, the higher the chances of success. References
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