Bring Breech Babies Back at 6 Months for Hip Dysplasia Check

Fran Lowry

March 16, 2010

March 16, 2010 (New Orleans, Louisiana) — Breech birth is the main risk factor for hip dysplasia. These babies can appear normal on ultrasound screening at 6 weeks, but need radiographic follow-up at 6 months to rule out subsequent developmental dysplasia of the hip, according to new research presented here at the American Association of Orthopaedic Surgeons 2010 Annual Meeting.

"We used to think that if the ultrasound at 6 weeks was normal, then the baby was going to be ok and that you could just discharge those patients and not have them return," said Meghan Imrie, MD, now at the Lucille Packard Children's Hospital in Palo Alto, California. Dr. Imrie was formerly at the Rady Children's Hospital in San Diego, California, where this study was conducted. "We know that some of these children may have persistent dysplasia and we recommend that they be brought back for repeat screening," she told Medscape Orthopaedics.

The investigators retrospectively reviewed the clinical data and imaging studies of all breech infants who were referred for orthopaedic evaluation over a 5-year period.

They found that, of the 300 breech babies in their review, 27% had abnormal screening ultrasounds at 6 weeks. These babies were treated with a Pavlik harness.

The remaining 73% of infants with normal 6-week ultrasounds were brought back for another clinical and radiographic check at 4 to 6 months, in accordance with the Rady protocol, Dr. Imrie explained. Of these, 29% had evidence of dysplasia and were treated with a Pavlik harness.

The diagnosis of dysplasia after a normal ultrasound was based on both radiographic and clinical parameters. Of the hips that were treated with a Pavlik harness, 62% had acetabular indices at least 2 standard deviations from the age-corrected average, compared with 26% of hips not treated.

These data support breech as the most important risk factor for hip dysplasia, Dr. Imrie said. "We therefore recommend careful and longitudinal evaluation of these patients with a careful newborn physical examination, an ultrasound at 6 weeks of age, and an anteroposterior pelvis and frog lateral radiograph at 6 months, because the risk of subsequent dysplasia is too high to discharge patients after a normal ultrasound."

The development of a baby's hip is a very dynamic process and changes over time, Dr. Imrie told Medscape Orthopaedics. "Some of the hips with subtle dysplasia that we see on x-ray may normalize on their own. But some do not. At this time, we don't have a good handle on which hips will normalize and which will not."

If the hip dysplasia does not normalize, this can lead to arthritis and surgery in the teen and adult years.

"Our philosophy is that it's much easier to treat a baby with a harness for a few months when they are little than to risk a big surgery when they are older," she said.

Perry L. Schoenecker, MD, professor of orthopaedic surgery at Washington University in St Louis, Missouri, who moderated the session, told Medscape Orthopaedics that he thinks the paper is very timely, "because it tells us we need to be very vigilant for the child with a hip that is potentially unstable."

Rady Children's Hospital had a low threshold for treating these children, he added. "This is probably good. Over half of their patients had to have treatment, and although there are some patients who may not have needed it, the treatment is pretty innocuous. The investigators have a point when they say that it is probably better to err on the side of caution by treating a few children unnecessarily than to undertreat and have a more difficult problem later on."

Dr. Imrie and Dr. Schoenecker have disclosed no relevant financial relationships.

American Association of Orthopaedic Surgeons (AAOS) 2010 Annual Meeting: Abstract 396. Presented March 11, 2010.


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