Physical examination for hip disloation

Developmental dysplasia of the hip (DDH) is an abnormality in the hip joint that is usually present from birth. Simply, there is no contact between the acetabulum and the femur.

In a normal hip, the head of the femur is a smooth rounded ball and the acetabulum is a smooth cup-like shape. The head of the femur and the acetabulum are in close contact, a little bit like in an egg cup. 

In DDH, there is an abnormality either in the shape of the head of the femur, the shape of the acetabulum , or the supporting structures arounds them. As a result, the acetabulum and femur are not in close contact. It may be a mild abnormality where there is some contact between them. This is called subluxation. 

It may be a severe abnormality where there is no contact between them and this is called dislocation.

The Ortolani test: The examiner's hands are placed over the child's knee with his/ her tumbs on the medial thigh and the fingers placing a gentle upward stress on the lateral thigh and greater trochanter area. With slow abduction, a dislocation and reducible hip will reduce with a described palpable 'clunk'.

The Barlow Maneuver is done by guiding the hips into mild adduction and applying a slight forward pressure with the thumb. If the hip is unstable, the femoral head will slip over the prosterior rim of the acetabulum, again producing a palpable sensation oof sublaxation or dislocation.

• Doctor lays baby on its back. They will bend the baby's knees and turn the thighs outwards. Whilst doing this, the doctor feels for a clunk, which feels similar to when a light switch is turned on. If the doctor feels this, then it may indicate that there is a problem with the tip.
• If a baby is 4-6 months, an ultrasound may be done, this usually takes 10-15 minutes. The baby will be laid down and the sonographer will place a cold gen on the other side where the abnormality is suspected. 
• They will gently press into the hip area, moving the hand-held sensor. The sensor sends out sound waves and picks up the returning echos. Pictures of the inside of the baby's body will be displayed on screen.
• In children ages over 4-6 months, an x-ray is more helpful. Various measurements are taken on the x-ray picture of the pelvis and femur to determine whether a child has DDH.
• The child will lay on the table so that the hip is positioned between the x-ray machine and a photographic table. The plate will be underneath the child in the table.
• The x-ray takes a fraction of a second, however the child needs to lie still so that the x-ray is not blurred. As the x-rays hit the photographic plate, the plate will capture a snapshot of the image.
• The image will then be transferred to a computer so that it can be studies on a screen and printed out.

A klunk, feeling similar to a light switch being turned on indicating a hip problem.

When DDH is suspected in a newborn, the parents may be simply advised to return for a review examination in a few weeks. This is because the hip may be unstable at birth in many newborn babies because the tissues are soft and lax. 

In most babies, the hip will become stable by itself by two months, as the soft tissues tighten. Sometimes, a baby's hips an be relocated into the correct position just through examination.

Positive: A positive result will be a clunk being heard, indicating the child has hip dysplasia. Treatment will be needed.

Negative: The child has no abnormalities in the hip. No treatment is needed.

Importance: If a chid's DDH is not diagnosed and treated early, they may develop arthritis of the hip joint causing pain and reduced movement. The treatment of DDH gets more complex and with less chance of success once the child's bones have fully developed.