Ultrasonography in the diagnosis and management of developmental hip dysplasia (UK Hip Trial): clinical and economic results of a multicentre randomised controlled trial

Diagnostic accuracy of static graf technique of ultrasound evaluation of infant hips for developmental dysplasia

INTRODUCTION

Ultrasound examination of infant hips is a widely used and accepted tool for the diagnosis and monitoring of developmental dysplasia of the hip. Its use and timing is still a focus of debate and its diagnostic accuracy has not been fully investigated.

METHOD

We have compared the ultrasound findings by the Graf technique with radiographic appearance (acetabular index) at 6 months of age.

RESULT

The negative predictive value of Ultrasound for DDH was 98% and was unaffected by the timing of the examination. The specificity and accuracy of the examination increased with age and was highest at 3 months of age.

CONCLUSION

Ultrasound examination of the infant hip by the static Graf technique is a safe and effective screening tool for the evaluation of DDH.

The success of management with the Pavlik harness for developmental dysplasia of the hip using a United Kingdom screening programme and ultrasound-guided supervision

We present the results of treatment of developmental dysplasia of the hip in infancy with the Pavlik harness using a United Kingdom screening programme with ultrasound-guided supervision. Initially, 128 consecutive hips in 77 patients were reviewed over a 40-month period; 123 of these were finally included in the study. The mean age of the patients at the start of treatment was five weeks (1 to 12). All hips were examined clinically and monitored with ultrasound scanning. Failure of treatment was defined as an inability to maintain reduction with the harness. All hips diagnosed with dysplasia or subluxation but not dislocation were managed successfully in the harness. There were 43 dislocated hips, of which 39 were reducible, but six failed treatment in the harness. There were four dislocated but irreducible hips which all failed treatment in the harness. One hip appeared to be successfully treated in the harness but showed persistent radiological dysplasia at 12 and 24 months. Grade 1 avascular necrosis was identified radiologically in three patients at 12 months.

Difficult-to-treat Ortolani-positive hip: improved success with new treatment protocol

BACKGROUND

The aim of this paper was to review the outcomes of treatment of dislocated but reducible (Ortolani-positive) hips.

METHODS

A comparative retrospective review was conducted of all patients aged younger than 6 months who presented for treatment of developmental dysplasia of the hip for two 10-year periods. The inclusion criteria consisted of a clinical evaluation documenting Ortolani-positive examination, no previous treatment, and an initial treatment with Pavlik harness only. Patients with insufficient follow-up, neuromuscular disease, provocative dislocatable hips, or dislocated but not reducible hips were excluded. In group 1 (1984-1994), treatment involved initiation of Pavlik harness and parental education at the time of initial diagnosis. Group 2 (1997-2007) was treated the same as group 1 with the addition of serial orthopaedic office-based ultrasound examinations and use of a hip abduction orthosis in hips remaining unstable after 3 weeks in the Pavlik harness. Records were assessed for successful achievement and maintenance of hip reduction, need for and type of further treatment, and development of avascular necrosis.

RESULTS

In group 1, the mean time of follow-up was 28 months. Forty-four (85%) of 52 hips were treated successfully. Eight patients required further operative treatment. In group 2, the mean follow-up to the final evaluation was 34 months. Forty-one (93%) of 44 hips were treated successfully. Three hips required further treatment. There were no documented cases of avascular necrosis in patients treated for orthoses only in either group.

CONCLUSIONS

In 1994, we presented a series of 52 Ortolani-positive hips (group 1) with a success rate of reduction of 85%. Now, our protocol for treating Ortolani-positive hips has evolved to include serial orthopaedic office-based ultrasound in all patients and use of a hip abduction orthosis in hips remaining unstable after 3 weeks in a Pavlik harness. Three previous studies at major centers reported successful reduction in only 63% to 71%. In group 2, our current success rate of 93% exceeds that previously reported by us and is significantly greater than these 3 previous studies (all P < 0.006). Furthermore, our current treatment module has decreased our rate of open reduction from 10% in group 1 to 5% in group 2. LEVEL OF RELEVANCE: Therapeutic study, level 3.

[Hip ultrasound screening in Germany. Results and comparison with other screening procedures]

General ultrasound screening programmes to determine DDH are still a matter of discussion due to a lack of evidence. To facilitate further discussions this review gives an overview of the international data and literature concerning the different screening policies taking into account the results of the German evaluation study from 1997 to 2002. General ultrasound screening programmes are established in Germany and Austria. The analysis of the German screening showed 535 cases of DDH with first operative procedure (age 10 weeks to 5 years) that were treated as inpatients: 66% underwent a closed reduction, 11% an open reduction and 23% an osteotomy of the acetabulum/femur. The number of children who had no ultrasound of the hip before diagnosis decreased from 22% in the first year to 8% in the last. The first ultrasound examination was without pathological findings in 12% of the cases. Capture-recapture estimates suggested that 52% of cases were reported, so that the incidence for first operation due to DDH was 0.26 per 1,000 live births in 1997. This is much lower than in other countries and 4/5 less than the time before screening with ultrasound in Germany. At most 42% of the cases might be preventable by an improvement of the screening programme, but at least 51% would not be prevented. The German ultrasound screening programme has proved to be effective. Improvement of economic efficiency is still possible. Therefore, the German programme with different screening times can be recommended.

Developmental dysplasia of the hip and occult neurologic disorders

Developmental dysplasia of the hip (DDH) is a neonatal condition with various causes. Neuromuscular dysplasia of the hip (NDH) is a sequel of neuromuscular disease, and generally presents later in childhood than DDH. Some evidence, however, supports a concept of a neuromuscular etiology of DDH: (1) a high prevalence of spinal dysraphism in DDH; and (2) abnormal sensory evoked potentials in 31% of DDH patients. To explore this suggestion we ascertained the presence of neuromuscular disease within a cohort of DDH patients, and asked whether the neuromuscular condition is the initial etiology of the dysplasia or a coincidental finding. We retrospectively reviewed patients presenting with DDH. Only those with an initial diagnosis of DDH and a subsequent diagnosis of a neuromuscular condition were assessed. Fifteen of 560 patients fulfilled the criteria, however the presence of true DDH within this group was minimal, as several cases emerged as early presenting NDH. We therefore believe it unlikely DDH has a substantial neurological etiology.

LEVEL OF EVIDENCE

Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Developmental dysplasia of the hip

In its severest form, developmental dysplasia of the hip is one of the most common congenital malformations. The pathophysiology and natural history of the range of morphological and clinical disorders that constitute developmental dysplasia of the hip are poorly understood. Neonatal screening programmes, based on clinical screening examinations, have been established for more than 40 years but their effectiveness remains controversial. Whereas systematic sonographic imaging of newborn and young infants has afforded insights into normal and abnormal hip development in early life, we do not clearly understand the longer-term outcomes of developmental hip dysplasia, its contribution to premature degenerative hip disorders in adult life, and the benefits and harms of newborn screening. High quality studies of the adult outcomes of developmental hip dysplasia and the childhood origins of early degenerative hip disease are needed, as are randomised trials to assess the effectiveness and safety of neonatal screening and early treatment.

Ultrasound in the diagnosis of developmental dysplasia of the hip in newborns. The European approach. A review of methods, accuracy and clinical validity

Based on soft evidence that ultrasound screening tends to reduce the rate of late developmental dysplasia of the hip (DDH) and the need for surgical interventions, different screening strategies including universal or selective ultrasound screening have been established in several European countries and centres during the last decade. We performed an extensive search for articles on ultrasound diagnosis of developmental dysplasia of the hip over the last 26 years. A few studies reported an adequate repeatability for the static [Graf, Morin, modified Morin (Terjesen)] and for the combined static/dynamic methods [modified Graf (Rosendahl)], while no such reports were found for the dynamic (Harcke) ultrasound techniques. The effect of newborn ultrasound screening on late DDH have been addressed in two randomised trials (RCTs), both concluding that both selective and universal ultrasound screening tend to reduce the prevalence of subluxed or dislocated DDH, thus without reaching statistical significance. Finally, several observational studies have shown that morphologically normal hips tend to remain normal with or without a co-existing instability, and 97% of sonographically immature hips tend to normalise spontaneously within 3 months. Two studies report on a similar pattern for mildly dysplastic, but stable hips. From the data available we suggest that selective ultrasound screening is worthwhile in areas with a high prevalence of late cases, given a well-organised, high-quality service can be provided.

Differences in risk factors between early and late diagnosed developmental dysplasia of the hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is common, affecting 7.3 per 1000 births in South Australia. Clinical screening programmes exist to identify the condition early to gain the maximum benefit from early treatment. Although these screening programmes are effective, there are still cases that are missed. Previous research has highlighted key risk factors in the development of DDH.

OBJECTIVE

To compare the risk factors of cases of DDH identified late with those that were diagnosed early.

METHODS

A total of 1281 children with DDH born in 1988-1996 were identified from the South Australian Birth Defects Register. Hospital records of those who had surgery for DDH within 5 years of life were examined for diagnosis details. Twenty seven (2.1%) had been diagnosed at or after 3 months of age and were considered the late DDH cases (a prevalence of 0.15 per 1000 live births). Various factors were compared with early diagnosed DDH cases.

RESULTS

Female sex, vertex presentation, normal delivery, rural birth, and discharge from hospital less than 4 days after birth all significantly increased the risk of late diagnosis of DDH.

CONCLUSIONS

The results show differences in the risk factors for early and late diagnosed DDH. Some known risk factors for DDH are in fact protective for late diagnosis. These results highlight the need for broad newborn population screening and continued vigilance and training in screening programmes.

Screening for developmental dysplasia of the hip: a systematic literature review for the US Preventive Services Task Force

BACKGROUND

Developmental dysplasia of the hip (DDH) represents a spectrum of anatomic abnormalities that can result in permanent disability.

OBJECTIVE

We sought to gather and synthesize the published evidence regarding screening for DDH by primary care providers.

METHODS

We performed a systematic review of the literature by using a best-evidence approach as used by the US Preventive Services Task Force. The review focused on screening relevant to primary care in infants from birth to 6 months of age and on interventions used in infants before 1 year of age.

RESULTS

The literature on screening and interventions for DDH suffers from significant methodologic shortcomings. No published trials directly link screening to improved functional outcomes. Clinical examination and ultrasound identify somewhat different groups of newborns who are at risk for DDH. A significant proportion of hip abnormalities identified through clinical examination or ultrasound in the newborn period will spontaneously resolve. Very few studies examine the functional outcomes of patients who have undergone therapy for DDH. Because of the high rate and unpredictable nature of spontaneous resolution of DDH and the absence of rigorous comparative studies, the effectiveness of interventions is not known. All surgical and nonsurgical interventions have been associated with avascular necrosis of the femoral head, the most common and most severe harm associated with all treatments of DDH.

CONCLUSIONS

Screening with clinical examination or ultrasound can identify newborns at increased risk for DDH, but because of the high rate of spontaneous resolution of neonatal hip instability and dysplasia and the lack of evidence of the effectiveness of intervention on functional outcomes, the net benefits of screening are not clear.

The significance of at-risk factors in ultrasound surveillance of developmental dysplasia of the hip. A ten-year prospective study

Of the 34,723 infants born between 1 June 1992 and 31 May 2002, the hips of 2578 with clinical instability or at-risk factors for developmental dysplasia of the hip were imaged by ultrasound. Instability of the hip was present in 77 patients, of whom only 24 (31.2%) had an associated risk factor. From the 'at-risk' groups, the overall risk of type-III dysplasia, instability and irreducibility was 1:15 when family history, 1:27 when breech delivery and 1:33 when foot deformity were considered as risk factors. Of those hips which were ultrasonographically stable, 88 had type-III dysplasia. A national programme of selective ultrasound screening of at-risk factors for the diagnosis of hip dislocation or instability alone cannot be recommended because of its low predictive value (1:88). However, the incidence of type-III dysplasia and hip dislocation or dislocatability in the groups with clinical instability, family history, breech position and possibly postural foot deformity as risk factors could justify a programme of selective ultrasound imaging.

Management of neonatal hip instability and dysplasia

The diagnosis and treatment of neonatal hip instability and dysplasia is controversial. Different countries have different algorithms and guidelines on which hips should be screened or treated. German speaking countries have introduced universal ultra sound hip screening programmes resulting in relatively high splintage rates in certain centres. Some Scandinavian centres have organised selective screening programmes with serial ultrasound observation of hip instabilities, leading to comparatively low splintage rates. Though most experts would treat clinical hip instability (confirmed by ultrasound evaluation), the natural history and epidemiology of dysplasia is less well understood. The treatment regimes for neonatal dysplasia are varied with wide differences in the rates of splintage. 'Late' dislocation may be secondary to prenatal dislocation (teratogenic), neonatal hip instability or to persistent major dysplasia of the hip. The term 'missed' dislocation should not be used as this suggests negligence on the part of the examiner, when this may not be the case. Which splint to use (rigid or dynamic), at what age, and for how long, are questions currently unresolved as no proper controlled trials have been undertaken. However, a sensible treatment algorithm can be advocated. Complications secondary to splintage are rare, though nerve damage, avascular necrosis of the hip, redislocation and skin problems have been described.

The effect of functional splinting on mild dysplastic hips after walking onset

Background

For treatment of Graf class IIb dysplastic hips at walking onset a treatment concept with abduction splints allowing patterns as walking and crawling under constant abduction control was investigated. However, as the splint still incapacitates child movements the research question remains whether the physiologically progressing maturation of hips can be significantly altered using such abduction splints for walking children.

Methods

Of 106 children showing late hip dysplasia, 68 children treated with the Hoffman-Daimler (HD-splint) abduction splint were compared with 38 children with neglect of the abduction treatment in this retrospective study. Radiographic analyses were performed measuring the development of the age dependent acetabular angle.

Results

The regression analysis for splint treatment showed a significant linear regression for both splint treatment and no splint treatment group (r² = 0,31 respectively r² = 0,33). No statistical difference between both treatment groups was apparent.

Conclusion

Considering the characteristics of this study, there seems to be no strong rationale supporting the use of an abduction device in growing children. As no significant difference between treatment groups is apparent, a future controlled prospective study on splinting effects can be considered ethically allowed.

Ultrasonography in screening for developmental dysplasia of the hip in newborns: systematic review

OBJECTIVE

To assess the accuracy and effectiveness of the screening of all newborn infants for developmental dysplasia of the hip (DDH) using ultrasound imaging, as is standard practice in some European countries but not in the United Kingdom, the United States, or Scandinavia.

DESIGN

Systematic review.

DATA SOURCES

Twenty three medical, economic, and grey literature databases (to March 2004), with no limitations of design or language; some references were provided by experts.

SELECTION OF STUDIES

Only diagnostic accuracy studies and comparative studies conducted in an unselected newborn population were eligible for the review. Two reviewers independently selected the studies and performed the quality assessment.

RESULTS

The review identified one diagnostic accuracy study, and this was of limited quality. In this study the reference standard was treatment up to age of 8 months or an abnormal ultrasound finding at age 8 months. Ultrasound screening had a sensitivity of 88.5% (95% confidence interval 84.1% to 92.1%), specificity of 96.7% (96.4% to 97.4%), a positive predictive value of 61.6% and a negative predictive value of 99.4%. Ten studies evaluated the impact of ultrasound in screening, but these too had various methodological weaknesses, limiting the reliability of their findings. Compared with clinical screening, general ultrasound screening in newborns may increase overall treatment rates, but ultrasound screening seems to be associated with shorter and less intrusive treatment.

CONCLUSIONS

Clear evidence is lacking either for or against general ultrasound screening of newborn infants for DDH. Studies that investigate the natural course of the disorder, the optimal treatment for DDH, and the best strategy for ultrasound screening are needed.

Assessing subgroup effects with binary data: can the use of different effect measures lead to different conclusions?

Background

In order to use the results of a randomised trial, it is necessary to understand whether the overall observed benefit or harm applies to all individuals, or whether some subgroups receive more benefit or harm than others. This decision is commonly guided by a statistical test for interaction. However, with binary outcomes, different effect measures yield different interaction tests. For example, the UK Hip trial explored the impact of ultrasound of infants with suspected hip dysplasia on the occurrence of subsequent hip treatment. Risk ratios were similar between subgroups defined by level of clinical suspicion (P = 0.14), but odds ratios and risk differences differed strongly between subgroups (P < 0.001).

Discussion

Interaction tests on different effect measures differ because they test different null hypotheses. A graphical technique demonstrates that the difference arises when the subgroup risks differ markedly. We consider that the test of interaction acts as a check on the applicability of the trial results to all included subgroups. The test of interaction should therefore be applied to the effect measure which is least likely a priori to exhibit an interaction. We give examples of how this might be done.

Summary

The choice of interaction test is especially important when the risk of a binary outcome varies widely between subgroups. The interaction test should be pre-specified and should be guided by clinical knowledge.

The hip trial: psychosocial consequences for mothers of using ultrasound to manage infants with developmental hip dysplasia

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.

Congenital abnormalities of the musculoskeletal system: Perinatal evaluation and long-term outcome

Many musculoskeletal malformations can be detected by prenatal US. Whether isolated or part of a syndrome, these anomalies can have a significant impact on the entire life of the individual. Nonfatal conditions may be subtle and become more recognizable in the second and third trimester. After delivery, radiography helps confirm the diagnosis. US, CT, and MRI all have a role in imaging the primary abnormality, the follow-up effects of treatment, and in monitoring for potential complications that may develop over time. Three-dimensional imaging has an increasing role, in US, CT, and MRI, both in the prenatal and postnatal periods.

Effect of ultrasound screening on the rate of first operative procedures for developmental hip dysplasia in Germany

BACKGROUND

Ultrasound screening for developmental hip dysplasia and early conservative treatment might prevent later hip operations. A national hip ultrasound-screening programme, undertaken during the first 6 weeks of life, was introduced across Germany in 1996 and was continued for 5 years. We assessed the rate of first operation on the hip during this programme.

METHODS

A national active surveillance programme of initial operations for developmental hip dysplasia was started in 1997 and continued for 5 years. Screening participation was assessed by a random digit dialing telephone survey. Cases were children aged between 10 weeks and 5 years at first operation, who had had no underlying disease leading to developmental hip dysplasia. Completeness of case ascertainment was validated with a capture-recapture study in a representative subsample. Calculated incidences were compared with previously established rates.

FINDINGS

About 90% of all children were screened. 147 cases in the first year, and between 81 and 105 for subsequent years were reported. Treatment included closed reductions 353 (66%), open reductions 61 (11%), and osteotomies 121 (23%). Developmental hip dysplasia was diagnosed by ultrasound before 6 weeks of age in 272 (55%) of cases, 64 (13%) were screened at the recommended time but had normal findings, 70 (14%) had delayed screening, and 89 (18%) were not screened. Capture-recapture estimates suggested that 52% of cases were reported. The corrected incidence for first operation was 0.26 per 1000 livebirths (95% CI 0.22-0.32).

INTERPRETATION

Ultrasound screening seems to prevent many, but not all, operations for developmental hip dysplasia. Rates of timely screening (ie, before 6 weeks of age) and training of doctors in ultrasound screening need to be improved.

Efficiency of alternative policy options for screening for developmental dysplasia of the hip in the United Kingdom

AIMS

To assess, using a decision model, the efficiency of ultrasound based and clinical screening strategies for developmental dysplasia of the hip.

METHODS

The additional cost per additional favourable outcome was compared for the following strategies: clinical screening alone using the Ortolani and Barlow tests; addition of static and dynamic ultrasound examination of the hips of all infants (universal ultrasound) or restricted to infants with defined risk factors (selective ultrasound); "no screening" (that is, clinical diagnosis only).

RESULTS

Ultrasound based screening strategies are predicted to be more effective but more costly than clinical screening or no screening. Estimated total costs per 100,000 live births are approximately pound 4 million for universal ultrasound, pound 3 million for selective ultrasound, pound 1 million for clinical screening alone, and pound 0.4 million for no screening. The relative efficiency of selective ultrasound and clinical screening is poorly differentiated, and depends on how infants are selected for ultrasound as well as the expertise of clinical screening examiners. If training costs less than pound 20 per child screened, clinical screening alone would be more efficient than selective ultrasound. Relative to no screening, each of the 16 additional favourable outcomes achieved as a result of selective ultrasound costs approximately pound 0.2 million, while each of the five favourable outcomes achieved through universal ultrasound screening, over and above selective ultrasound, costs approximately pound 0.3 million.

CONCLUSIONS

Policy choice depends on values attached to the different outcomes, willingness to pay to achieve these and total budget.

Performance, treatment pathways, and effects of alternative policy options for screening for developmental dysplasia of the hip in the United Kingdom

AIMS

To compare, using a decision model, performance, treatment pathways and effects of different newborn screening strategies for developmental hip dysplasia with no screening.

METHODS

Detection rate, radiological absence of subluxation at skeletal maturity and avascular necrosis of the femoral head, as favourable and unfavourable treatment outcomes respectively, were compared for the following strategies: clinical screening alone using the Ortolani and Barlow tests; the addition of static and dynamic ultrasound examination of the hips of all infants (universal ultrasound) or restricted to infants with defined risk factors (selective ultrasound); "no screening" (that is, clinical diagnosis only).

RESULTS

Universal or selective ultrasound detects more more affected children (76% and 60% respectively) than clinical screening alone (35%), results in a higher proportion of affected children with favourable treatment outcomes (92% and 88% respectively) than clinical screening alone (78%) or no screening (75%), and the highest proportion of these achieved without recourse to surgery (64% and 79% respectively) compared with clinical screening alone (18%). However, ultrasound based strategies are also associated with the highest number of unfavourable treatment outcomes arising in unaffected children treated following a false positive screening result. The detection rate of clinical screening alone becomes similar to that reported for universal ultrasound when based on studies using experienced examiners (80%) rather than junior medical staff (35%).

CONCLUSION

From the largely observational data available, ultrasound based screening strategies appear to be most sensitive and effective but are associated with the greatest risk of potential adverse iatrogenic effects arising in unaffected children.