Developmental dysplasia of the hip joint

Dysplasia of the hip joint ( hip dysplasia , dysplasia coxae congenita, congenital dislocation of the hip) is often a congenital malformation : the fossa of the hip joint is too small or insufficiently deep. Up to 4% of newborns suffer from it. In extreme cases, the head of the femur can partially or completely fall out of the socket. In these cases, we talk about subluxation , or dislocation, of the hip joint.

What causes hip dysplasia ?

Hip dysplasia is one of the most common congenital malformations . It is usually a developmental disorder of the hip, more precisely, the joint socket is too small and the head of the hip is therefore insufficiently covered. As a further consequence, so-called hip dislocation may develop .

• Hip dysplasia: the socket of the hip joint is not yet sufficiently developed.
• Hip dislocation: the head of the hip joint slips out of the socket.

If the head of the hip partially falls out of the socket, we speak of subluxation , if it falls out completely, we speak of luxation. Dysplasia contributes to this dislocation , on the one hand, and on the other hand, a faulty position of the neck of the femur .

Hip dysplasia can be caused by various risk factors . Hip dysplasia occurs equally often in both sexes, but hip dislocation occurs 5x to 7x more often in girls than in boys. Possible causes include lack of space in the uterus . Twins, children born earlier and children after caesarean section or after breech birth are affected more often. Hormonal factors during pregnancy and hereditary disposition also play a role .

Hip dysplasia is a congenital malposition of the hip and cannot therefore be prevented. However, the risk of dysplasia developing into dislocation can be reduced. Premature stretching positions in the hip joint are particularly disadvantageous. In order for the hip joint to mature, it must continue to maintain the flexion that a child would assume under normal circumstances in the mother’s womb. Therefore, it is recommended that a child after birth:

• wear in scarves
• wrap them so that the hip joint is bent,
• do not prematurely place the baby on the tummy.

What symptoms can occur?

Dysplasia of the hip joint itself usually does not lead to perceptible difficulties in newborns. However, if the developmental anomaly is not recognized and treated in time, hip dislocation may occur. Children cannot extend the affected leg sufficiently to the side. Other signs may include delayed walking, weight-bearing pain in the hernia or hip area, or bilateral lameness. As a late consequence , arthrosis of the hip joint, coxarthrosis , may occur in adulthood , because due to a small or completely missing roof of the fossa, there is an unfavorable transfer of weight from the thigh to the pelvis, and this also leads to premature wear of the hip joint.

Parents can recognize hip dysplasia under the given circumstances by external signs:

• the baby’s legs are of different lengths,
• the legs cannot be stretched evenly,
• the child’s buttocks are located at different heights.

Most of the time, these signs only appear when the luxation has occurred. In case of bilateral dislocation, there is no asymmetry, but in compensation, excessive curvature of the lumbar spine occurs in these children .

How is the diagnosis made?

A child’s hip joint can mature only by the end of the second year of life. Correct and timely diagnosis is the most essential prerequisite for successful treatment. Using a physical examination, a pediatrician can detect only part of the hip joint disease based on external symptoms. A special examination is a so-called Ortolani test. It consists in peeling, if the head of the hip joint falls out of the socket due to pressure and stretching in the first months of life. The diagnostic standard is an ultrasound examination of the hip . It does not hurt or burden the infant. In doing so, the ratio of the head of the hip joint and the hip socket is assessed and measured.

In the Czech Republic, the disease is targeted using the triple sieve method – 3 consecutive examinations. The first ultrasound examination of the hip in the first week of age is specified in the mother and child card . This examination usually takes place in the hospital after birth. After a home birth, parents can contact a pediatrician or orthopedist regarding this examination . A second ultrasound follows at six to nine weeks of age. In the event of an unusual finding, or during therapy , the joint must be regularly checked. Between the 12th and 16th a week after the child’s age, a clinical examination and ultrasound screening are performed again . If there is diagnostic confusion, an X- ray of the hip is added . If everything is normal, the child is removed from the register and further checks are no longer necessary.

As the ossification of the head of the hip joint and the iliac fossa progresses, the informative value of ultrasound decreases, because the ultrasound waves do not penetrate the bones . In order to assess the progress, it is therefore necessary to give priority to an X-ray examination from the second year of age .

How is the treatment?

Therapy should be started as soon as possible so that the hip joint can mature quickly and to shorten the treatment period as much as possible and to avoid surgeries or possible consequences at a later time (e.g. limitation of mobility, permanent pain, necessity of hip replacement). Depending on how hip dysplasia is developed, different measures come into play. The goal is to always keep your legs bent and slightly extended.

• Wide package: This can treat mildly developed diagnosed hip dysplasia already in the first weeks of life. For this, a towel folded to a width of about 15 centimeters is used and placed between the diaper and the clothes, or two diapers are used.
• Abduction Briefs: Abduction briefs (also called abduction stirrups or braces) consist of a shoulder belt, a body belt and padded leg bands. They are worn over clothing and should only be removed when changing diapers and bathing. This way, the legs are better fixed than with wide packaging.
• Pavlík stirrups: Pavlík stirrups consist of one chest belt and two leg belts. Their length must be measured and regularly checked by a pediatrician or orthopedist. They help to press the head of the hip in the right direction into the socket.
• Gypsum spike: Serves convalescence in severe cases. It usually extends from the lower rib cage to the infant’s legs and has a free space for a diaper.
• Hip surgery: It may be necessary for very severe hip dysplasias, if all conservative methods such as wearing abduction pants, stirrups, rails or plaster spikes have not brought the desired success, or when the defect was recognized late. The goal is that the head of the hip joint is better covered, so that the center of gravity of the body is distributed over a larger area. With the introduction of hip ultrasound in infants, there was a drastic decrease in the number of open hip surgeries, which is about 14 surgeries per 100,000 newborns.
• Correction of hip dislocation (dislocation): In case of dislocation, the hip must be dislocated again and then stabilized for a certain period of time to prevent further dislocation. This stabilization takes place either using stirrups or plaster spikes.

The duration of treatment depends on the age of the child at the beginning of therapy and the condition of the hip joint. It is often enough to put on abduction panties for three to six days. In most cases, with early treatment adjusted to the individual condition of the hip joint, its complete maturation occurs.

Who can I contact?

The diagnosis is determined either already in the newborn in the hospital, or later at the regular time by the pediatrician and orthopedist. These specialist doctors are also responsible for conservative treatment , i.e. for all non-operative measures. Operative procedures are always performed in a hospital.