CauseEtiology

There are basically three different causes of hip dysplasia: mechanical causes genetic causes hormonal causes

Mechanical causes
Genetic causes
Hormonal causes

ClinicSymptoms

The patient’s medical history (medical anamnesis) should be focused on the risk factors mentioned above. Other important questions are when the first running attempts were made. Whether a limp was noticed.

Whether asymmetries exist in the area of the buttocks. Whether increased hollow back formation is noticeable when standing. If the hip joint is dislocated, the femoral head is higher.

In the case of a unilateral dislocation, therefore, asymmetry of the gluteal folds occurs. However, it is not permissible to conclude that every wrinkle asymmetry must necessarily be a hip dislocation. In the case of a bilateral luxation, there is no asymmetry because both hips are dislocated.

However, compensatory hip dislocation in these children leads to increased hollow back formation (hyperlordosis). (see: Hip dysplasia in children)During the examination of the hip joint, the stability of the hip joint is especially checked. Special attention is paid to the stability and dislocation of the joint.

Especially the examination method according to Ortolani should be mentioned here. In this type of examination, an attempt is made to dislocate the hip joint by applying external pressure on the femoral head or at least to place it on the edge of the pelvis. By changing the position of the femoral head, the examiner now tries to make the femoral head jump back into the acetabulum, which can be perceived as a clearly perceptible snap or click.

This phenomenon can be seen as a positive Ortolani sign. In a healthy hip joint, the Ortolani sign cannot be triggered. The examination is problematic in the case of a hip luxation (femoral head is not in the socket), which does not return to the socket.

The Ortolani sign cannot be triggered in this case either. Critics of this examination method complain that the femoral head could be damaged by the snap. The ultrasound of the infant’s hip is the most important diagnostic tool for the diagnosis of hip dysplasia in an infant.

Since large parts of the hip joint are not yet bony, but only cartilaginous, the X-ray image has only limited significance with regard to early diagnosis. Ultrasound (sonography) of the hip joint, on the other hand, can make soft tissue structures of the joint visible. The cartilaginous part of the acetabular roof and the femoral head can be well assessed by sonography with regard to dysplasia.

It should be performed routinely at U2 and U3. The method of ultrasonic examination of the infant hip was developed by the Austrian Professor Dr. Graf (Stolzalpe) in the early 1980s. The advantage of this method is that it is free of any radiation exposure (no X-rays).

It can therefore be repeated as often as desired. Furthermore a dynamic examination is possible. This means that the hip joint can be examined under motion and the behaviour of the femoral head to the acetabulum can be assessed under motion.

With increasing ossification of the femoral head and acetabulum, the informative value of the ultrasound decreases. Since the ultrasound waves cannot penetrate the bone, an ultrasound examination for hip dysplasia assessment can be carried out until the end of the first year of life, after which x-ray examination is superior. Professor Graf developed two measuring angles for the evaluation of the acetabular roof as an assessment aid.

Using the acetabular roof angle alpha and the cartilage roof angle beta, the degrees of dysplasia can be assessed, taking into account the age of the child, and forms of therapy can be derived from this. Hip type 1a ? >60° | ?

<55° | none necessary Hip type 1b | ? >60° | ? >55° | none necessary, control hip type 2a | ?

50-59° | ? >55° | none or wide wrap Hip type 2b | ? 50-59° | ?

<70° | spread treatment hip type 2c | ? 43-49° | ? 70-77° | spread treatment by hip flexion splint hip type 2d | ?

43-49° | ? >77° | abduction treatment with secure fixation hip type 3a | ? <43° | ?

>77° | hip luxated, reduction (spherical) and plaster fixation hip type 3b | ? <43° | ? >77° | hip luxated, reduction and plaster fixation, additional cartilage structure disorders in the acetabular roof detectable Hip type 4 | ?

<43° | ? >77° | hip luxated, reduction (spherical reduction) and plaster fixationAn X-ray is rarely taken before the first year of life. It is absolutely necessary for surgical planning.

As a rule, a so-called pelvic overview x-ray (BÜS) is made. The pelvis with the hip joints is X-rayed from front to back (a. p. = anterior – posterior). The position of the femoral head and acetabulum is assessed on this X-ray.

Different measured values are also important here.Important are especially here:

Ménard – Shenton – Line
The pantile roof angle = AC – angle according to Hilgenreiner
The CE – angle (center – corners – angle) according to Wiberg
The CCD – angle (Centrum – Collum – Diaphysis – Angle = Femoral neck – Shaft – Angle)

The Ménard – Shenton – line represents the extension of the inner part of the femoral neck and the lower pubic branch (symphysis). This should result in a harmonious, almost semi-circular structure. Cf.

the blue arc in the child’s x-ray to the right of a healthy hip joint If this line appears interrupted, stepped or not round, it is suspected that the femoral head is not located centrally in the socket. The cause may be hip dysplasia or hip luxation. In the case of more severe hip dysplasia (type 2d -4), the femoral head must first be brought back into the acetabulum (reduction).

The Pavlik bandage, for example, is suitable for this. It is fixed in the hip joint and in this position by a very strong flexion. All procedures have in common, however, that the fixed position of the femoral head can lead to a circulatory disorder.

As a result, parts of the femoral head can die off and permanently affect the function of the hip joint. Fixation If the reduction result cannot be maintained, fixation with splints and plaster may be considered. The so-called fat white plaster is frequently used.

In this case, the hip joint is flexed by 100 – 110° and spread out by approx. 45°. As a rule, this type of plaster is well tolerated by children.