Thomas
R M, Urquhart D S, Wefers B.
Neonatal Intensive Care Unit, Northwick Park Hospital, Watford Rd, Harrow, Middlesex HA1 3UJ
SMJ 2006 51(1): 57
Abstract
The
role of universal primary ultrasound screening for detection of developmental
dysplasia of the hip of the newborn remains controversial in Britain. Two
infants in whom ultrasonography was reported to show no evidence of
developmental dysplasia in the newborn period, but who later presented with
acetabular dysplasia and subluxation requiring surgery, are presented.
Case
Reports
Case
1
A
dislocatable left hip was detected on routine neonatal examination at 24 hours
of age. A consultant orthopaedic surgeon confirmed that the hip was Barlow test
positive on day 3 of life, but an ultrasound scan was reported to show no
evidence of hip dysplasia. A paediatric radiologist experienced in the scanning
of newborn hips performed the ultrasound scan, and a second experienced
paediatric radiologist reviewed the scans. At 4 months of age, both hips were
deemed to be clinically stable by the same orthopaedic surgeon, but left
acetabular dysplasia with subluxation was diagnosed on dynamic ultrasonography.
Adductor psoas tenotomy and closed reduction of the left hip was undertaken at 8
months of age. At 22 months, the child was walking and the radiograph showed
that the acetabulum was developing normally.
Case
2
A
dislocatable left hip was detected on routine neonatal examination at 28 hours
of age. Both hips appeared normal on static sonographic assessment, performed by
an experienced paediatric radiologist at 12 days of age, and reviewed by a
second radiologist. The infant was lost to follow up and re-presented at 8
months of age when the mother observed reduced movement of the right leg.
Dislocation of the right hip was confirmed radiologically. Adductor psoas
tenotomy and open reduction of the right hip was undertaken at 11 months of age.
At 20 months of age the child was walking, but there was some residual dysplasia
of the right hip on radiograph.
Discussion
The
success of routine clinical screening in reducing, but not abolishing late
presentation of developmental dysplasia of the hip is well documented (1).
A Medical Research Council working party review of primary screening in
the United Kingdom found that surgery was required for late diagnosed congenital
dislocation of the hip in 0.78 per 1000 live births, which represented 70%
children reported to the national surveillance programme (2). Other studies
evaluating the role of clinical screening have shown low rates of late diagnosed
congenital dislocation of the hip (CDH) requiring surgery and support
continuation of clinical screening (3, 4). An Australian population-based study
of clinical screening has shown a late detection rate of only 2 - 4 % (0.19 per
1000 live births) requiring surgery, and attribute their success to the quality
of the training of the testers and the organisation of the screening programme
(4). Some European countries,
notably Germany and Austria, have adopted primary neonatal ultrasound screening
of the hip following the publications of Graf (5). The high treatment rates for
hip dysplasia detected on routine sonographic screening in Europe have concerned
orthopaedic surgeons in Britain and North America. Dynamic tests of hip
instability increase the usefulness of ultrasound examination (6,7). Engesaeter
et al found that even in a group of 100 infants at high risk of hip instability,
only dynamic assessment of stability, but none of the standard sonographic
measurements of acetabular depth and femoral head cover, correlated with outcome
at 3 months of age (8).
There
has been no published population-based study to allow epidemiological assessment
including the incidence of late-presenting CDH, after apparently normal neonatal
ultrasound screening. Advocates of
hospital-based primary neonatal ultrasound screening of the hip in the United
Kingdom have demonstrated that late-presenting congenital dislocation of the hip
can be virtually eliminated, but such a screening programme requires a highly
dedicated team making extraordinary efforts to ensure that all neonates are
screened and followed up (9). Recent publications from a Medical Research
Council Working Party reporting on research initiated by the Department of
Health to assess the current screening programme in the United Kingdom and the
potential role of ultrasound screening, have explored various screening options
focussing on health outcomes and cost (10, 11). The authors have concluded that
it is not feasible to recommend a single national approach to this complicated
medical problem, particularly when local resources are so variable.
Clinical
guidelines and studies which aim to improve the outcome of this important and
disabling childhood condition by developing a more scientific basis for primary
screening should continue to include both clinical and sonographic evaluation.
Our cases serve to remind clinicians that long term follow up of all infants
with clinical signs of hip instability in the newborn period is mandatory, even
if the initial ultrasound scan is considered to be normal.
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