| It is normal practice in the UK to screen all babies for hip instability at birth as it is believed that treating a baby's unstable hip in the early weeks is better for normal hip development. Usually treatment involves holding the baby's legs apart in an abduction splint. However there is some uncertainty about when treatment should begin and how long treatment should last and which babies should be treated. It is believed that the use of ultrasound to image a baby's hips could inform doctors which baby to treat, when to treat and for how long, but there had been no large scientific study to see if ultrasound really worked or whether there were any unforeseen side effects. Treating babies unnecessarily increases the risk of complications due to splintage and the financial costs to both parents and the health service.
The aim of the study was to see if, following a clinical diagnosis of hip instability, using ultrasound reduced the usage of splints without doubling the risk of late treatment. It also looked at the relative costs of the treatment both to parents and the health service and the psychosocial implications. The psychosocial results have yet to be published so are not included in this article.
This was a randomised-controlled trial (RCT) which is a trial of an intervention where results are compared from two groups. Participants in one group (the intervention or experimental group) receive the intervention (in this case the ultrasound examination), and participants in the other group (the control group) do not. This is one of the most rigorous methods for comparing treatments. Participants in the trial are assigned to a group "at random" (rather like tossing a coin). 629 infants were enrolled from 33 centres in the UK. 314 children were allocated to the ultrasound group and 315 to the no-ultrasound group.
Babies were entered into the trial if their hips were thought to be unstable after the usual clinical examination of the hips at birth (the Ortolani-Barlow tests). Babies in the ultrasound group had an ultrasound before treatment started. Doctors treating children in the no-ultrasound group were not to use an ultrasound to guide the treatment. Apart from these differences both groups received the normal type of treatment as practiced in the hospital. Economic data (costs to both the health service and parents) were collected by questionnaires and published data from trusts, NHS and other studies; and psychosocial data was obtained by questionnaires.
The main aim of treatment is to give a baby a hip that is and remains pain free and functional throughout life. The study did not have the resources to do such a long term follow up, though the data has been tagged with NHS numbers should funding become available in the future. For this study the major clinical outcome was a normal x-ray at 12-14mths or 24mths if required. A secondary outcome was the amount of treatment required.
Fewer children in the ultrasound group had treatment (usually with splints) in the first two years than did those in the non-ultrasound group. (See chart) The most common splint was the Pavlik harness with the Aberdeen/Craig splint following. There was little difference between the two groups recording the number of babies needing surgery in the first two years of life (ultrasound group 7%, no-ultrasound group 8%). The results did not show a cost saving associated with the use of ultrasound, but did show a saving of up to £127 per patient for hospital costs. There was evidence that family costs were substantial especially when treatment was involved. The ultrasound group had slightly lower costs than the no-ultrasound group (but this was not statistically significant).
The findings of the Hip Trial have reduced the uncertainly about the effectiveness of using ultrasound to inform management of infant hip instability (DDH). The UK The National Screening Committee has recommend that ultrasound be used in the management of clinical hip instability. However the trial paper proposes that aspects of screening and management are still unclear. Notably that benefit or harm associated with the widespread use of ultrasound to screen infants with risk factors for DDH, but clinically stable hips, is not known. It also points out that ultrasound might be used as a primary screening test i.e. all babies have an ultrasound at birth. However this is not part of UK practice and in countries where primary screening has been introduced there has been up to a 10-fold increase in abduction splintage with all the attendant risks. It also points out that not enough is known about the effectiveness of abduction splintage and recommends that a large multicentre trial of abduction splintage is needed.
More reading:
Elbourne D, Dezateux C, Arthur R, Clarke N, Gray A, King et al on behalf of the UK Collaborative Hip Trial Group Ultrasonography in the diagnosis and management of developmental hi dysplasia (UK Hip Trial): clinical and economic results of a multicentre randomised controlled trial, The Lancet, Vol. 360, pp2009-2017. (December 2002)
This article was first printed in the steps magazine and externally reviewed by Diana Elbourne, Professor of Health Care Evaluation, Medical Statistics Unit, London School of Hygiene and Tropical Medicine, June 2003.
THE HIP TRIAL: psychosocial consequences for mothers of using ultrasound to manage infants with developmental hip dysplasia
F Gardner1, C Dezateux2, D Elbourne3, A Gray4, A King5 and A Quinn5 on behalf of the Collaborative Hip Trial Group
1 Department of Social Policy and Social Work, University of Oxford, Oxford, UK
2 Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, London, UK
3 Medical Statistics Unit, London School of Hygiene and Tropical Medicine, London, UK
4 Health Economics Research Centre, Department of Public Health, University of Oxford
5 National Perinatal Epidemiology Unit, University of Oxford
Correspondence to:
Dr Gardner
Department of Social Policy and Social Work University of Oxford,, Barnett House, Wellington Square, Oxford OX1 2ER, UK
Background: The hip trial aimed to assess clinical effectiveness, economic and psychosocial costs, and benefits of ultrasound imaging (US) compared with conventional clinical assessment alone to guide the management of infants with neonatal hip instability.
Objective: To report on psychosocial consequences for mothers and the developing mother-child relationship of US, and associations between abduction splinting and maternal psychosocial distress.
Design: Multicentre randomised controlled trial.
Setting: Thirty three hospitals in the United Kingdom and Ireland.
Participants, interventions: A total of 629 infants with neonatal hip instability randomised to US examination or clinical assessment alone before treatment decision. Questionnaires were completed by 561 (89%) mothers at 8 weeks and 494 (79%) at 1 year.
Main outcome measures: Anxiety, postnatal depression, parenting stress assessed by standardised questionnaires. Maternal concerns about hip problems were assessed using the Infant hip worries inventory.
Results: At 8 weeks, there were no differences between US and non-US groups of the trial in maternal anxiety (mean difference (MD) 1.2, 95% confidence interval (CI) 3.2 to 0.8), depression (MD 0.0, 95% CI 0.7 to 0.8), parenting stress (MD 1.2, 95% CI 2.8 to 0.4), or other measures. The same pattern was evident at 1 year. In an explanatory analysis, early splinting was associated with increased anxiety at 8 weeks (MD 3.8, 95% CI 1.7 to 5.9) and increased level of hip worries at 8 weeks (MD 6.8, 95% CI 5.6 to 7.9) and 1 year (MD 1.3, 95% CI 0.3 to 2.4).
Conclusions: Although early splinting is associated with maternal anxieties, US is not associated with any increase or reduction in psychosocial effects on mothers. Together with the clinical findings, this suggests that the use of US allows reduction in splinting rates without increased risk of adverse clinical or psychosocial outcomes.
Abbreviations: DDH, developmental dysplasia of the hip; EPDS, Edinburgh postnatal depression scale; NHI, neonatal hip instability; PSI, parenting stress index; STAI, Spielberger state-trait anxiety inventory
Keywords: abduction splinting; hip instability; maternal depression; psychosocial; ultrasound
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