hip-dysplasia

What is it?

Hip dysplasia is the most frequent skeletal malformation observed at birth and regards the loss of the correct position of the femoral head (upper part of the long bone of the thigh) inside the acetabular cavity (the “pocket” at the level of pelvis). It is mainly due to a delay of the development of the hip joint during the intrauterine life, probably caused by an alteration of the primary nuclei of growth (primary damage).

If not treated, it can evolve and for this reason it is also called developmental dysplasia of the hip

What are the causes?

The causes are still unknown. Several theories have been developed but so far none of them has a definitive scientific value. However, several risk factors exist reducing the space to perform various movements during intrauterine life predisposing to hip’s malformation (twins, oligoigramnios, breech presentation, fetal macrosomia).

Other risk factors are related to familiarity. It has been documented that in case of one parent with hip dysplasia the risk for the newborn is 12%, which increases to 36% in the case of dysplasia present in one parent and one sibling.

Does hip dysplasia only affect females?

In most cases the female sex is more affected (ratio females / males: 7/1) especially if first born. But males can also be affected.

Can dysplasia affect both hips?

Yes, dysplasia can be bilateral. In the case of monolateral dysplasia, the affected side is usually the left one.

How and when is the diagnosis made?

An accurate observation of spontaneous movements of the newborn, lower limbs leg length and skin pigs symmetry as well as the correct execution of the maneuvers of Ortolani and Barlow are fundamental for the diagnosis.

Clinical evaluations should be performed immediately after birth as well as in the following months / years of growth by pediatricians and/or pediatric orthopedic surgeons.

skin pigs asymmetry

What is hips ultrasound?

It is an extremely specific examination permitting visualization of bony and cartilagineous structures of the hip.

It is a harmless and non-invasive examination using the ultrasound to visualize neonatal hip, the same technique used for the visualization of the child during intrauterine life. The duration is a few minutes and it is performed in the outpatient clinic. The newborn is positioned on each side (lateral decubitus) with the parents’ help, and its execution is performed by positioning a probe covered by heated gel.

Up to what age can neonatal hip ultrasound be performed?

Neonatal hip ultrasound is recommended for all newborns of both sexes within the first 2/3 months of life. In case of risk factors it is recommended to be performed within the first 45 days of life.

Around the 5th to 6th month of life visualization of the hip is not possible due to the ossification of the growth nucleus of the femoral head. Therefore, an X ray of the pelvis should be performed for the morphological evaluation of both hips.

What is hip arthrography and when is it performed?

It is a minimally invasive examination performed in the operating room under slight sedation. It is a radiographic hip evaluation after the injection of a small quantity of contrast liquid (dye) that allows visualization of the cartilaginous (non-ossified) part of the joint, not visible on standard radiographs. It also permits the evaluation of the hip’s mobility, highlighting the presence of instability that could compromise the correct development of the joint.

Information obtained is useful to determine the type of morphological alteration of the hip joint and its stability for the decision of the best treatment (conservative or surgical) for each patient

Can hip dysplasia be treated early?

Yes. According to age and type/degree of dysplasia there are several types of early treatment

1. Harness: these devices permit the correct positioning of the femoral head inside the acetabular cavity. Duration of treatment depends on age and severity of hip dysplasia. Hip ultrasounds are performed every 5-6 weeks until normal hip’s morphology is observed.

The harness is well tolerated by the child, easy to use by the family and does not compromise the child’s growth

2. Pelvi-malleolus plaster (plaster pant): in case of dysplasia associated to instability. The plaster is useful to ensure the correct position of the femoral head inside the acetabular cavity. Pelvi-malleolus plaster is performed in the operating room under slight sedation. Hips radiographic and/or arthrography is also performed to evaluate the morphology of the joint, the degree of dysplasia, hip’s stability highlighting the best position where the femoral head is well placed inside the acetabular cavity. Its removal occurs after about 5-6 weeks in the operating room or in the outpatient clinic. Parents are immediately trained on how to keep the plaster in good condition and how to manage it (diaper’s change).

The plaster is well tolerated by the newborns and after removal spontaneous and painless mobility is observed immediately.

Are other controls recommended after treatment?

According to the morphological alteration of the hip after treatment observed during hip’s ultrasound and/or pelvis x ray, the pediatric orthopedic surgeon will decide future controls (clinical and radiographic) until puberty.

What can be done in case of untreated or not appropriately treated hip dysplasia?

Based on the clinical radiographic and/or arthrographic aspect, the pediatric orthopedic surgeon establishes the type of morphological alteration and decides the most appropriate treatment.

In case of instability but with a good morphological aspect of the joint, surgery to re-tension the articular caspula is recommended, followed by pelvi-malleolus plaster to guarantee the best position of the femoral head inside the acetabular cavity.

In case of bony deformities osteotomy can be performed at the level of the mal-developed bony part (periacetabular osteotomy in case of acetabular’s cavity defect; derotational, and/or shortening and/or varus osteotomy of the proximal femur, in case of femoral defect)

Is hip dysplasia invalidating?

Only if left to itself and not treated properly. All patients treated conservatively or surgically have a normal life without any limitations.