Developmental Dysplasia of the Hip Flashcards
What is developmental dysplasia of the hip (DDH)?
A problem with the way the hip joint develops
When is DDH present from?
Usually present from birth, although it may develop later
When is the outcome for DDH excellent?
When diagnosed and treated early in a young baby
What happens if treatment for DDH is delayed?
It is more complex, and has less chance of being successful
Describe the head of the femur in a normal hip
It is a smooth, rounded ball
Describe the acetabulum in a normal hip
It is a smooth, cup-like shape
Where is the abnormality in DDH?
Shape of the head of the femur, the shape of the acetabulum, or supporting structures around them
What is the result of abnormalities in the femur, acetabulum, or supporting structures in DDH?
The acetabulum and the femur are not in close contact
What is the spectrum of severity of DDH, in terms of the relationship between the acetabulum and the femur?
It can be a mild deformity, where there is some contact between them (subluxation), or a severe abnormality where there is no contact (dislocation)
What are the risk factors for DDH?
- Female gender
- Family history
- Oligohydraminos
- First-born child
- Breech delivery
- Neuromuscular disorders
Give 2 neuromuscular disorders that increase the risk of DDH?
- Cerebral palsy
- Meningomyelocele
When is screening for DDH done?
It is part of the physical examination of the newborn and 6-8 week old babies
Does normal examination in the neonatal period does not preclude a subsequent diagnosis of DDH?
No
What are the clinical features of DDH in children under 3 months old?
- Asymmetry
- Positive Ortolani and Barlow test
Where may asymmetry be noted in DDH in under 3 month olds?
- Gluteal or thigh skin folds
- Limb length discrepancy
In what age group should you perform the Ortolani and Barlow tests?
Under 3 months
How is the Ortolani test performed?
You apply gentle forward pressure to each femoral head in turn
What do the results of the Ortolani test show?
Palpable movement suggests the hip is dislocated or subluxed, but reducible
How is the Barlow test performed?
You apply gentle backwards pressure to the head of each femur in turn
What do the results of the Barlow test suggest?
A subluxable hip is suspected on the basis of complete or partial displacement
Why are the Ortolani and Barlow tests only done in under 3 month olds?
They are useful in neonates, but become difficult by 2-3 months of age
What are the clinical features of DDH in 3-6 month olds?
- Unilateral dislocation
- Asymmetry of hip position
- Hip may be in fixed position
- Galeazzi sign
When might the hip be in a fixed position in DDH in 3-6 month olds?
If the hip is dislocated
How is the Galeazzi sign identified?
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
What does a positive Galeazzi sign indicate?
May signify hip dislocation
What are the clinical features of DDH in older children?
- Limited abduction when fully flexed
- May walk on toes on affected side
- Painless limp
What investigations are done in DDH?
- Dynamic ultrasound or hip ultrasound
- Pelvic x-rays
- CT and MRI scanning may be needed
What is the purpose of a dynamic ultrasound in DDH?
Assess hip stability and acetabular development in infants
When is hip ultrasound useful in DDH?
In children under 4.5 months
When are pelvic x-rays useful in DDH?
Older infants and children, once the femoral head ossification centre has developed
What is the limitation of CT and MRI scanning in DDH?
Require sedation
What happens to most unstable hips by 2-6 weeks of age?
They stabilise spontaneously
When does DDH require treatment?
Any hip that remains dislocatable or pathologically unstable by 2-6 weeks requires prompt treatment
What is the first line treatment for DDH in children younger than 6 months?
Bracing
How is bracing achieved in DDH?
With a dynamic flexion-abduction orthrosis, called a Pavlik harness
Should the Pavlik harness be left on at all times?
Yes
What is the purpose of the Pavlik harness?
It maintains hip reduction, and can be adjusted as the child grows and the hip stablises
What are the main risks of treatment with a Pavlik harness?
- Avascular necrosis
- Temporary femoral nerve palsy
When is surgery an option in DDH?
- In children whom non-operative treatment has failed
- In children diagnosed after 6 months of age
What is the most common surgical procedure used in DDH?
Closed reduction with adductor or psoas tenotomy
What must a closed reduction with adductor or psoas tenotomy for DDH be followed by?
3-4 months in plaster cast or abduction brace
What happens as a child gets older, with regards to management?
The older the child, the more likely an extensive procedure will be required
What more extensive procedure may be required in an older child with DDH?
Open reduction and soft tissue stabilisation of the joint, followed by a cast
What complications can result from surgery in DDH?
- Re-dislocation
- Stiffness
- Blood loss
- Avascular necrosis of capital femoral epiphysis
Why is DDH an important condition?
Because it is a major cause of childhood disability
What are the potential long term complications of DDH?
- Premature degenerative joint disease
- Low back pain
