Developmental Dysplasia of the Hip Flashcards

1
Q

What is developmental dysplasia of the hip (DDH)?

A

A problem with the way the hip joint develops

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2
Q

When is DDH present from?

A

Usually present from birth, although it may develop later

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3
Q

When is the outcome for DDH excellent?

A

When diagnosed and treated early in a young baby

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4
Q

What happens if treatment for DDH is delayed?

A

It is more complex, and has less chance of being successful

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5
Q

Describe the head of the femur in a normal hip

A

It is a smooth, rounded ball

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6
Q

Describe the acetabulum in a normal hip

A

It is a smooth, cup-like shape

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7
Q

Where is the abnormality in DDH?

A

Shape of the head of the femur, the shape of the acetabulum, or supporting structures around them

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8
Q

What is the result of abnormalities in the femur, acetabulum, or supporting structures in DDH?

A

The acetabulum and the femur are not in close contact

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9
Q

What is the spectrum of severity of DDH, in terms of the relationship between the acetabulum and the femur?

A

It can be a mild deformity, where there is some contact between them (subluxation), or a severe abnormality where there is no contact (dislocation)

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10
Q

What are the risk factors for DDH?

A
  • Female gender
  • Family history
  • Oligohydraminos
  • First-born child
  • Breech delivery
  • Neuromuscular disorders
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11
Q

Give 2 neuromuscular disorders that increase the risk of DDH?

A
  • Cerebral palsy

- Meningomyelocele

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12
Q

When is screening for DDH done?

A

It is part of the physical examination of the newborn and 6-8 week old babies

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13
Q

Does normal examination in the neonatal period does not preclude a subsequent diagnosis of DDH?

A

No

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14
Q

What are the clinical features of DDH in children under 3 months old?

A
  • Asymmetry

- Positive Ortolani and Barlow test

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15
Q

Where may asymmetry be noted in DDH in under 3 month olds?

A
  • Gluteal or thigh skin folds

- Limb length discrepancy

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16
Q

In what age group should you perform the Ortolani and Barlow tests?

A

Under 3 months

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17
Q

How is the Ortolani test performed?

A

You apply gentle forward pressure to each femoral head in turn

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18
Q

What do the results of the Ortolani test show?

A

Palpable movement suggests the hip is dislocated or subluxed, but reducible

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19
Q

How is the Barlow test performed?

A

You apply gentle backwards pressure to the head of each femur in turn

20
Q

What do the results of the Barlow test suggest?

A

A subluxable hip is suspected on the basis of complete or partial displacement

21
Q

Why are the Ortolani and Barlow tests only done in under 3 month olds?

A

They are useful in neonates, but become difficult by 2-3 months of age

22
Q

What are the clinical features of DDH in 3-6 month olds?

A
  • Unilateral dislocation
  • Asymmetry of hip position
  • Hip may be in fixed position
  • Galeazzi sign
23
Q

When might the hip be in a fixed position in DDH in 3-6 month olds?

A

If the hip is dislocated

24
Q

How is the Galeazzi sign identified?

A

The child is examined supine, with the hips and knees flexed to 90 degrees, and the heigh of each knee compared, and the height of each knee is compared. Unilateral femoral shortening is a positive Galeazzi sign

25
Q

What does a positive Galeazzi sign indicate?

A

May signify hip dislocation

26
Q

What are the clinical features of DDH in older children?

A
  • Limited abduction when fully flexed
  • May walk on toes on affected side
  • Painless limp
27
Q

What investigations are done in DDH?

A
  • Dynamic ultrasound or hip ultrasound
  • Pelvic x-rays
  • CT and MRI scanning may be needed
28
Q

What is the purpose of a dynamic ultrasound in DDH?

A

Assess hip stability and acetabular development in infants

29
Q

When is hip ultrasound useful in DDH?

A

In children under 4.5 months

30
Q

When are pelvic x-rays useful in DDH?

A

Older infants and children, once the femoral head ossification centre has developed

31
Q

What is the limitation of CT and MRI scanning in DDH?

A

Require sedation

32
Q

What happens to most unstable hips by 2-6 weeks of age?

A

They stabilise spontaneously

33
Q

When does DDH require treatment?

A

Any hip that remains dislocatable or pathologically unstable by 2-6 weeks requires prompt treatment

34
Q

What is the first line treatment for DDH in children younger than 6 months?

A

Bracing

35
Q

How is bracing achieved in DDH?

A

With a dynamic flexion-abduction orthrosis, called a Pavlik harness

36
Q

Should the Pavlik harness be left on at all times?

A

Yes

37
Q

What is the purpose of the Pavlik harness?

A

It maintains hip reduction, and can be adjusted as the child grows and the hip stablises

38
Q

What are the main risks of treatment with a Pavlik harness?

A
  • Avascular necrosis

- Temporary femoral nerve palsy

39
Q

When is surgery an option in DDH?

A
  • In children whom non-operative treatment has failed

- In children diagnosed after 6 months of age

40
Q

What is the most common surgical procedure used in DDH?

A

Closed reduction with adductor or psoas tenotomy

41
Q

What must a closed reduction with adductor or psoas tenotomy for DDH be followed by?

A

3-4 months in plaster cast or abduction brace

42
Q

What happens as a child gets older, with regards to management?

A

The older the child, the more likely an extensive procedure will be required

43
Q

What more extensive procedure may be required in an older child with DDH?

A

Open reduction and soft tissue stabilisation of the joint, followed by a cast

44
Q

What complications can result from surgery in DDH?

A
  • Re-dislocation
  • Stiffness
  • Blood loss
  • Avascular necrosis of capital femoral epiphysis
45
Q

Why is DDH an important condition?

A

Because it is a major cause of childhood disability

46
Q

What are the potential long term complications of DDH?

A
  • Premature degenerative joint disease

- Low back pain