“NEVER miss an opportunity to examine a baby’s hips” is sound advice for GPs, paediatricians and early childhood nurses in promoting the early detection of developmental dysplasia of the hip (DDH) in infants, according to paediatric orthopaedic surgeon, Associate Professor Nicole Williams.
Professor Williams was given this advice during her specialty training, and she now passes on these words to other clinicians.
“If [clinicians] just feel lots of babies’ hips and see what normal movement is and see what a stable and unstable hip feels like, then we get much better at detecting the [hips] that are abnormal and require early intervention,” Professor Williams told MJA InSight.
Professor Williams’ comments come as the MJA publishes a Narrative Review addressing evidence gaps in the screening, diagnosis and management of DDH internationally.
DDH is a spectrum of conditions ranging from mild acetabular dysplasia of a reduced and stable hip, to an irreducibly dislocated hip.
“When left untreated or missed during early screening, DDH can lead to debilitating long term issues, including early-onset osteoarthritis of the hip, pain, limping, and the need for a total hip replacement in early adulthood,” wrote the authors.
The authors of the review, who include the International Hip Dysplasia Institute (IHDI) study group, found insufficient evidence to support universal ultrasound screening, but recommended selective ultrasound screening for at-risk infants (breech presentations, family history, or history of clinical instability).
The authors also recommended that at-risk children with a normal initial ultrasound be followed up with an anteroposterior pelvis x-ray at 6, 12 and 24 months. However, they noted that this recommendation might be “excessive”, before solid prospective evidence was available, given the recommendation was based on level 3 evidence and expert opinion.
They also recommended brace treatment as a sensible first-line approach for infants under 6 months with dislocated hips, the most severe form of DDH, based on level 2 evidence indicating a 79% success rate.
In an MJA InSight podcast, lead author Dr Emily Schaeffer, a post-doctoral research fellow at Canada’s British Columbia Children’s Hospital and the University of BC, said that a lack of longitudinal data as well as variable diagnostic definitions had hindered the development of a consensus on DDH diagnosis and management.
“We are trying to look back at what’s been reported from retrospective, single-centre, small studies that really aren’t able to be compared because definitions aren’t fully reported in terms of … a dislocated hip versus an unstable hip,” she said.
The Narrative Review authors noted that the IHDI’s multicentre, international prospective study was seeking to address the many unanswered questions on DDH.
Associate Professor David Osborn, Clinical Associate Professor at the University of Sydney and senior neonatologist at the Royal Prince Alfred Hospital, said that there was room for improvement in Australia’s approach to DDH screening.
“There’s an eclectic mix of guidelines from different states, individual hospitals and health networks,” said Professor Osborn, who was an author of the 2013 Cochrane Review on DDH screening.
Professor Osborn said that many of the guidelines around Australia were in keeping with the American Academy of Paediatrics guideline that recommended repeated clinician examination of infants with consideration of ultrasound in high risk infants.
However, he said that the recommendation in the MJA Narrative Review for a follow-up x-ray in at-risk infants with an initial normal ultrasound screening result was “contentious”.
“A single article has led to this recommendation, so it is quite contentious and needs duplication through more research,” Professor Osborn said.
Associate Professor Peter Cundy, Associate Professor in the Discipline of Orthopaedics at the University of Adelaide, said that his group’s research had shown a breech birth to be protective against a late diagnosis of DDH.
“It’s well known that babies [with a breech presentation] are more prone to this condition, so when a doctor sees a breech baby, a little lightbulb goes on in their head that says ‘this baby could have DDH, so I will double-check and triple-check to make sure the hips are okay’,” Professor Cundy said.
“The effect of that has been that we don’t see breech babies presenting late with DDH.”
Professor Cundy said that this suspicion of DDH should extend to all babies.
“What we need is for GPs, paediatricians and well baby nurses to think ‘this baby could have DDH’ every time they see a baby, whether they [had a breech presentation], have a family history of DDH or are a normal baby,” he said. “We need to make more noise about this condition to make sure clinicians think about it and test for it. We believe the best test is still clinical screening with Barlow and Ortolani tests, but if there is doubt, then, yes, an ultrasound is appropriate after 6 weeks of age.”
Professor Williams said that she was concerned about recommendations that promote the selective screening of at-risk babies.
“We have been increasingly using [selective screening] in Australia, and we have found that our ability to detect dislocated hips [early] is going down, rather than up,” she said. “So, selective screening seems to be lulling us into a false sense of security.”
Professor Williams pointed to the South Australian research she co-authored with Professor Cundy and colleagues that found that between 1988 and 1996, 2.1% of infants with DDH were diagnosed at 3 months of age or older; then, between 2003 and 2009, 11.5% of cases were diagnosed at older ages.
“Back in the 1980s and 1990s – when we did do a very careful examination – we were very good at detecting dislocated hips clinically. And now that we are increasingly relying on ultrasound, I think people are assuming that babies with risk factors are going to get ultrasounds, and assuming that babies that don’t have risk factors are at very low risk, so they aren’t examining them carefully,” said Professor Williams, whose team is conducting a systematic review in an effort to inform future Australian guidelines.
Professor Cundy said that the well intended trend towards swaddling babies in the early 2000s may be partly responsible for a surge in late diagnosed DDH in the mid-2000s.
“Babies were wrapped to try to get them to sleep better, but it had the effect of arresting the natural development of the baby’s hip, causing many of these babies to present late with dysplasia,” he said.
Earlier hospital discharge of new mothers and babies may have also hindered the early detection of dysplastic hips, Professor Cundy said.
He said many babies now went home 12-18 hours after delivery limiting the examination opportunities in the neonatal period.
“We should encourage good clinical screening, we should encourage mothers not to wrap their babies’ lower limbs, and we should encourage baby-wearing [using baby-carriers that strap the baby across their parent’s chest, abducting the baby’s hips],” Professor Cundy said.
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