Developmental Dysplasia of the Hip
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Direct answer
Developmental dysplasia of the hip is a spectrum of abnormal development of the acetabulum and femoral head, ranging from a lax but seated hip to a fully dislocated one. Early detection is the aim, because treatment in the first months is simple and effective. The Ortolani and Barlow tests detect instability at birth, while ultrasound confirms the diagnosis in high-risk infants.
What you must remember
- Ortolani test: a reduction clunk as a dislocated hip, flexed and abducted, slides back into the acetabulum.
- Barlow test: adduction of the flexed hip pushes a dislocatable hip out of the socket, producing a clunk.
- Risk factors: female sex, first-born status, breech presentation, family history and oligohydramnios.
- Laterality: the left hip is more often affected, and bilateral disease is less common than unilateral.
- Ultrasound: the Graf method assesses hip morphology in high-risk infants, usually from about six weeks of age.
- Pavlik harness: a dynamic flexion-abduction brace used for infants under about six months, in which excess abduction risks avascular necrosis.
- Late presentation: a limp, Trendelenburg gait, leg length discrepancy and restricted abduction in a walking child, which usually needs surgery.
A graded pathway from newborn check to treatment
Screening aims to catch dysplasia before walking begins, when treatment is simple. Clinical tests are most useful in the first weeks, and the pathway then moves towards imaging and bracing.
- Newborn examination: perform Ortolani and Barlow tests on every neonate, and note limited abduction or asymmetric thigh creases.
- Risk assessment: infants with breech presentation or a family history should undergo ultrasound even when the examination is normal.
- Ultrasound confirmation: use the Graf method for hip morphology, typically from about six weeks, when the femoral head is measurable.
- Harness treatment: start a Pavlik harness for stable, dislocatable or dislocated hips under about six months, with repeat ultrasound to confirm reduction.
- Escalation: when the harness fails or the infant is older, arrange closed reduction under anaesthesia, or open reduction with or without a pelvic osteotomy.
- Follow-up: monitor acetabular development on repeat imaging until skeletal maturity, since residual dysplasia can persist.
Where the exam tries to catch you
Questions on this topic usually test the age at which each method works.
- Trap: relying on Ortolani and Barlow tests after several months of age Correct: the clunk fades as the hip becomes fixed, so older children are assessed by imaging and by limited abduction.
- Trap: forcing the hip into abduction to fit a harness Correct: excessive abduction can damage the blood supply to the femoral head, so the harness holds the hip within a safe range.
- Trap: dismissing a normal-looking newborn hip in a breech infant Correct: high-risk infants still need ultrasound, because dysplasia may be missed on examination alone.
Frequently asked questions
Which tests examine the newborn hip for developmental dysplasia?
The Ortolani and Barlow tests examine the newborn hip for developmental dysplasia. Ortolani detects a dislocated hip that reduces with a clunk on abduction, while Barlow detects a hip that can be dislocated by adduction. Both are most useful in the first few weeks of life.
Why must a Pavlik harness avoid excess abduction?
A Pavlik harness must avoid excess abduction because forced abduction can damage the blood supply to the femoral head and cause avascular necrosis. The harness is adjusted so the hip stays flexed and abducted within a safe range, and its position is checked with repeated ultrasound.
What is the Graf method used for in developmental dysplasia of the hip?
The Graf method is the standard ultrasound technique for assessing hip morphology in developmental dysplasia of the hip. It measures the bony and cartilaginous acetabular angles, allowing classification of hip maturity and stability, and is usually performed from about six weeks of age.
How does late developmental dysplasia present in a walking child?
Late developmental dysplasia in a walking child presents with a limp, a Trendelenburg gait, leg length discrepancy and restricted hip abduction, often noticed by parents. Radiographs confirm the diagnosis, and treatment often requires surgical reduction, sometimes with a pelvic osteotomy.