DDH

Question 1

What is DDH?

Question 2

What is the spectrum of DDH?

Answer 2

1. Dysplasia
2. Subluxation
3. Dislocation
4. Teratologic hip
   5.

Question 3

What is the incidence?

Answer 3

• 1 in 100 of dysplasia
• 1 in 1000 of dislocation

Question 4

Risk factors?

Answer 4

• Females (6:1 ratio)
• Native americans (Rare in Africans)
• Firstborn
• Family history
• Maternal smoking
• Oligohydramnios
• Breech presentation

Question 5

What percentage are bilateral?

Question 6

What is the proposed etiology?

Question 7

What is a limbus?

Question 8

What are the secondary barriers to reduction?

Question 9

Physical exam findings in patients >3 months?

Answer 9

• Barlow
  
  • dislocates a dislocatable hip by adduction and depression of the flexed femur
• Ortolani
  
  • reduces a dislocated hip by elevation and abduction of the flexed femur
• Galeazzi
  *

Question 10

Physical exam findings in patients 3-12 months?

Answer 10

• Limited hip abduction
• Klisic sign
  
  • line from the long finger placed over the greater trochanter and the index finger over the ASIS should point to the umbilicus
  • if the hip is dislocated, the line will point halfway between the umbilicus and pubis

Question 11

Physical exam findings in patients >12 months?

Answer 11

• Trendelenburg gait
• Lumbar lordosis
  *

Question 12

Signs on X ray for dislocation?

Answer 12

• Hilgengreiner’s line
  
  • horizontal line through the right and left triradiate cartilage
  • femoral head ossification should be inferior to this line
• Perkin’s line
  
  • line perpendicular to Hilgenreiner’s line through a point at the lateral margin of the acetabulum
  • femoral head ossification should be medial to this line
• Shenton’s line
  *

Question 13

Signs on x ray for dysplasia?

Answer 13

• Acetabular index
  
  • angle formed by Hilgenreiner’s line and a line from a point on the lateral triradiate cartilage to a point on lateral margin of acetabulum
  • should be < 25° in patients older than 6 months
• Centre edge angle*

Question 14

What are the measurements on US imaging?

Answer 14

*

Question 15

Describe the US classification for DDH?

Answer 15

Graf Classification

Question 16

What are potential blocks to reduction identifiable on arthrogram?

Answer 16

1. Inverted labrum
2. Inverted limbus
3. Ligamentum teres
4. Pulvinar
5. Iliopsoas and capsule
6. TAL

Question 17

What is the non-op treatment of DDH?

Answer 17

• Non-op
  
  • Pavlik harness
    
    • <6 months and reducible hip
  • Closed reduction and spica casting
    
    • 6-18 months or failure of pavlik harness

Question 18

What are the operative options in DDH?

Answer 18

• Open reduction and spica casting
  
  • >18 months
• Open reduction and femoral osteotomy
  
  • Usually best in <4y
  • Used if changes on femoral side
• Open reduction and pelvic osteotomy
  
  • Best for >4y
  • Used if changes on acetabular side

Question 19

What are the risks of Pavlik harnessing?

Answer 19

• AVN
  
  • If abduction >60 degrees
  • due to impingement of the posterosuperior retinacular branch of the medial femoral circumflex artery
• Femoral nerve palsy
  
  • Flexion >90 degrees
• Pavlik disease
  
  • erosion of the pelvis superior to the acetabulum and prevention of the development of the posterior wall of the acetabulum due to prolonged positioning of dislocated hip in flexion and abduction