Developmental dysplasia of the hip (DDH)

Definition

• A spectrum of disorders ranging from complete dislocation of the femoral head to a reduced hip joint with acetabular dysplasia

Types:

1. Complete hip dislocation.

2. Partial hip subluxation.

3. Hip dysplasia (incomplete development).

Risk factors:

• family history - may reflect laxity of ligaments
• Race- common in white 
• Breech  presentation - Exaggerated positioning in acute flexion and adduction in utero may occur
• Female sex - the presence of maternal relaxin in the fetal circulatory system
• large fetal size 
• First born child

Galeazzi's test

• With the child is lying on a flat surface, flex the hips and knees so the heels rest flat on the table, just distal to the buttock . 
• A dislocated hip is signaled by relative shortening of the thigh compared with the normal leg, as shown by the difference in knee height level. 
• This test is almost always useless in children under 1 year of age and is negative if dislocation is bilateral.

Barlow's test

• This is a provocative test that picks up an unstable but located hip; it is unsuitable for a dislocated hip. 
• Thighs are gently grasped in the hand, with the thumb at the lesser trochanter and fingers at the greater trochanter . The hip is adducted slightly and gently pushed posteriorly with the palm. 
• Detection of "pistoning," or the sensation of the femoral head subluxating over the posterior rim of the acetabulum, is a positive finding.

Ortolani's test:

• This test detects hips that are already dislocated. 
• The flexed limb is grasped as in Barlow's test. The hip is abducted while the femur is gently lifted with the fingers at the greater trochanter. 
• In a positive test, there will be a sensation of the hip reducing back into the acetabulum. 

Clinical Manifestations

In newborn:

• We can diagnose DDH in this period by positive Ortolani’s test or Barlow’s test.
• Asymmetry of the skin fold may help, but its not specific. 
• Shortening of the limb at this age doesn’t exist.
• We cant use X-rays because the acetabulum and proximal femur are cartilaginous and wont be shown on X-ray.
• USG is the best method to Dx.

In the early childhood:

• Parents notice asymmetry of creases of groin, limitation of movement of affected hip or click every time hip is moved

In older children:

• Complaints of limping, waddling gait (bilateral DDH), Trendelenburg’s gait (unilateral DDH), lumbar lordosis, limitation of hip abduction, etc…

X-ray

Von Rosen view:

hips abducted 45º & medially rotated.

Anteroposterior.

We draw a line through the central axis of the femoral shaft.

        in normal hip ( ossific nucleus )will be inside the acetabulum.

        in dislocated hip it will be above acetabulum.

Delayed development of ossific nucleus / smaller

Horizontal line of Hilgenreiner:

   drawn between upper ends of tri-radiate cartilage of the acetabulum.

Vertical line of Perkins:

  drawn from the lateral edge of the acetabulum vertical to horizontal line.

4 quadrants:

Normal hip: the ossification center of the femoral hip lower medial quadrant.

Dislocated hip: upper lateral quadrant.

Acetabular index:

    angle between horizontal line of Hilgenreiner and the line between the two edges of the acetabulum.

    normal hip 20º-300 

    dilocated or dysplastic hip ≥ 30º

Shenton’s line:

    semicircle between femoral neck and upper arm of obturator foramen, in dislocated hip this line is broken.

Treatment:

The earlier the better. 

Exact treatment depends on patient age at presentation and degree of involvement

Goal is to:

1.Flex and abduct hips.

2.Reduce femoral head and maintaining it.

Reduction can be achieved by closed manipulation , traction followed by closed reduction and opened reduction  

 maintenance can be done using plaster cast(frog leg or Batchelor) or splint (von Rosen’s splint)

• Acetabular reconstruction procedure
• Salter’s osteotomy
• Chiari’s pelvic displacement osteotomy 
• Pemberton’s pericapsular osteotomy

• From (0-6 months)  

A dislocated hip at this age may spontaneously reduce over 2-3 weeks if the hip is held in a position of flexion. 

Reduction by closed manipulation and maintained with plaster cast or splint

• From 6 months -2 year

Gentle closed reduction of the dislocation under a general anesthetic and maintenance of a located position for 2-3 months in a hip spica cast usually stabilize the joint

• From the age of 2-6 years:

open reduction with osteotomy

• 6-10 years

No treatment for bilateral
Open reduction with reconstruction for unilateral

• After 10 years

Only indication for treatemnt is pain. If only one hip affected total hip replacement may be done.