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Developmental Dysplasia of Hip
KEY FACTS
Terminology
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Definition: Spectrum of progressive hip abnormalities developing during infancy, including dysplastic acetabulum & femoral head malpositioning
Imaging
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Ultrasound is modality of choice for infants 0-4 months old
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Radiographs necessary after 4-5 months
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Proximal femoral epiphysis & acetabulum ossify, blocking ultrasound beam & limiting evaluation
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CT/MR used in limited circumstances
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Immediately after operative reduction
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Evaluation of long-term complications
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Clinical Issues
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Palpable click/clunk upon stress (Ortolani & Barlow), asymmetric skin or gluteal folds, leg length discrepancy
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Much more common in girls, breech positioning, oligohydramnios, Caucasians
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Treatment correlation with ultrasound
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Normal: α angle ≥ 60°, coverage ≥ 50%, no instability
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Immature hip (applies only to infants < 3 months of age): α angle 50-59°, coverage 45-50%, no instability
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Small risk of delayed developmental hip dysplasia (DDH); follow-up recommended to confirm normal development
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Mild DDH: α angle 50-59°, coverage 40-50%
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Infants ≥ 3 months usually treated with Pavlik harness to flex, abduct, & externally rotate hips
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Moderate DDH: α angle ≤ 50°, coverage ≤ 40%, any instability
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Treated with harness; repeat q4 weeks until normal
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Severe DDH: Gross acetabular dysplasia, dislocated hip
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No improvement in harness by 4 weeks → surgical hip reduction & casting required
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Delayed diagnosis/treatment can result in irreversible dysplasia requiring iliac osteotomy/shelving procedure
The US transducer is placed over the lateral hip with slight posterior obliquity
to obtain a coronal flexed image. Note the use of 2 hands (& the foot pedal to save images).
to obtain a coronal flexed image. Note the use of 2 hands (& the foot pedal to save images).
Coronal flexed US in the same patient shows the unossified femoral head
, the straight segment of the iliac bone
, & a line drawn along the acetabular roof
. The α angle is measured between these lines & should be ≥ 60⁰. The iliac line should cover the femoral head by ≥ 50%. Note the triradiate cartilage
& ischium
.
, the straight segment of the iliac bone , & a line drawn along the acetabular roof . The α angle is measured between these lines & should be ≥ 60⁰. The iliac line should cover the femoral head by ≥ 50%. Note the triradiate cartilage & ischium .
Frontal radiograph in a 6-month-old boy with a left hip “clunk” reveals severe left developmental dysplasia of the hip. The acetabular roof is quite steep
, & the ossified femoral head is small
with superolateral dislocation.
, & the ossified femoral head is small with superolateral dislocation.
Intraoperative arthrogram shows contrast outlining a dysplastic, mostly unossified left femoral head
. Note that the acetabular roof is quite steep
. The femur is dislocated from the severely dysplastic & shallow joint space
. This child required an osteotomy.
. Note that the acetabular roof is quite steep . The femur is dislocated from the severely dysplastic & shallow joint space . This child required an osteotomy.
TERMINOLOGY
Definitions
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Developmental dysplasia of hip (DDH): Spectrum of progressive hip abnormalities in infancy resulting in acetabular dysplasia with femoral head malpositioning
IMAGING
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