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| Patient's
Information |
| Developmental Dysplasia of the
Hip (DDH) |
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| Practice Guidelines for Early Detection
of Dislocated Hips |
| Developmental dysplasia of the hip (DDH)
includes frank dislocation, partial dislocation, instability
and inadequate formation of the acetabulum. The term "developmental"
is preferred over the term "congenital." Developmental
more accurately reflects the disorder because these abnormalities
may not be present at birth. The newborn screening surveys suggest
that dislocation of the hip may occur at a rate of 1.0 to 1.5
cases per 1,000 newborns. |
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| Risk Factors |
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The hip is at risk of dislocation in
the 12th gestational week, in the 18th gestational week, in
the final four weeks of gestation, when mechanical forces play
a role, and in the postnatal period. Oligohydramnios and breech
presentation are associated with an increased risk of DDH. Studies
suggest that as many as 23 percent of infants with breech presentation
are affected. Postnatally, positioning of the infant may play
a role.
The incidence of DDH is higher in girls, perhaps because females
are more susceptible than males to the maternal hormone relaxin,
which may contribute to ligamentous laxity. The left hip is
affected three times more often than the right hip, which may
be related to the left occiput anterior position of most nonbreech
infants. |
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| Clinical Features |
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| There are no pathognomonic
signs for a dislocated hip. Asymmetry of the thigh or
gluteal folds, limb length discrepancy and restricted
motion (especially abduction) can be signs of a dislocated
hip. The Ortolani and Barlow tests are useful for assessing
hip stability in the newborn. A palpable "clunk"
during either maneuver is considered a strongly positive
sign for dislocation of the hip. A dislocatable hip is
described as having a distinctive clunk, whereas a subluxable
hip |
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| is characterized by a feeling of looseness,
a sliding movement without the true clunks felt on the Ortolani
and Barlow maneuvers. By eight to 12 weeks of age, the Ortolani
and Barlow tests are no longer useful, regardless of the status
of the femoral head. At this age, capsule laxity decreases and
muscle tightness increases. The most reliable sign in the three-month-old
infant is limitation of abduction. Other features of DDH at
this age include asymmetry of the thigh folds, relative shortness
of the femur with the hips and knees flexed (called the Allis
or Galeazzi sign) and a discrepancy of leg lengths. |
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| Ortolani Test |
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| Path physiology: Femoral head which
is dislocated and displaced superiorly, posteriorly is reduced
with this maneuver. |
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| Barlow Test |
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| Pathophysiology: Unstable Femoral head
is dislocated with this maneuver |
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| Real-time ultrasonography is the most
accurate method for imaging the hip in the first few months
after birth. Ultrasonography provides visualization of the cartilage,
hip stability and features of the acetabulum. Ultrasonography
is identified as the technique of choice for clarifying a physical
finding suggestive of DDH, for assessing a high-risk infant
and for monitoring DDH. Radiographs are of limited value during
the first few months of life but are more reliable in infants
four to six months of age, when the ossification center develops
in the femoral head. According to the guideline, ultrasonography
and radiography are equally effective imaging studies for detecting
DDH in infants four to six months of age. |
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| Recommendations |
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| The accompanying algorithm gives an
overview of the recommendations for DDH screening in infants. |
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Female Infants. The
newborn risk of DDH is 19 per 1,000 in girls. If the newborn
examination is negative or equivocally positive, the hips should
be reexamined when the infant is two weeks of age.
Infants with a Positive Family History of DDH.
When the family history is positive, the newborn risk is 9.4
per 1,000 for boys and 44.0 per 1,000 for girls. When the newborn
examination is negative or equivocally positive in boys with
a family history, reevaluation of the hips at two weeks of age
is recommended. In girls with a family history of DDH, ultrasonographic
examination at six weeks of age or radiographic examination
of the pelvis and hips at four months of age is recommended.
Breech Presentation. The newborn
risk of breech presentation is 120 per 1,000 for girls and 26
per 1,000 for boys. When the newborn examination is negative
or equivocally positive in boys with breech presentation, reevaluation
of the hips should be conducted at regular intervals. In girls,
because of their absolute risk of 120 per 1,000, ultrasonographic
examination at six weeks of age or radiographic evaluation of
the pelvis and hips at four months of age is recommended. The
guideline also notes that there is a high incidence of hip abnormalities
in children born breech. For this reason, ultrasonographic examination
remains an option in all children born breech.
The hips must be examined at every well-baby visit (two to four
days for newborns discharged in less than 48 hours after delivery
and by one month, two months, four months, six months, nine
months and 12 months of age). |
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