High incidence of congenital dislocation of the hip in Northern Ireland

The epidemiology of developmental dysplasia of the hip in Japan: Findings from a nationwide multi-center survey

BACKGROUND

It has been reported that the national incidence of developmental dysplasia of the hip (DDH) has decreased in Japan. This is because of prevention activities after birth since around 1970. However, cases of late-diagnosed DDH have still been noted in some children's hospitals. There has been no recent survey of DDH in Japan. The purpose of this study was to investigate the current epidemiology of DDH using a comprehensive nationwide survey.

METHODS

A questionnaire was sent to orthopedic surgeons in 1987 facilities nationwide, who were asked to complete and return a survey card on each DDH patient treated between April 2011 and March 2013.

RESULTS

A total of 783 (39%) facilities completed and returned the card. Of these, 79% reported no cases of DDH-related dislocation over the 2-year period, while the remaining facilities reported 1295 cases. The characteristics of children diagnosed with DDH-related dislocation were as follows: girls (89%), left side involvement (69%), bilateral involvement (4%), positive family history (27%), first-born (56%), and pelvic position at birth (15%). Seasonal variation showed an increase in DDH incidence among those born in the winter. Overall, 199 cases (15%) were diagnosed at >1 year of age, and these included 36 cases diagnosed very late, at >3 years of age. The majority of the 199 cases of late diagnosis had received earlier routine screening at <1 year of age.

CONCLUSION

The characteristics of the children diagnosed with DDH nationwide were similar to past data from local regions. However, many children were diagnosed late (>1 year of age), particularly in the more populous regions. The findings identify a need for improved early routine screening for DDH in Japan.

Epidemiology of developmental dysplasia of the hip within the UK: refining the risk factors

PURPOSE

The epidemiology and risk factors for developmental dysplasia of the hip (DDH) are still being refined. We investigated the local epidemiology of DDH in order to define incidence, identify risk factors, and refine our policy on selective ultrasound screening.

METHODS

With a cohort study design, data were prospectively recorded on all live births in our region from January 1998 to December 2008. We compared data on babies treated for DDH with data for all other children. Crude odds ratios (ORs) were calculated to identify potential risk factors. Logistic regression was then used to control for interactions between variables.

RESULTS

There were 182 children born with DDH (with a total of 245 dysplastic hips) and 37,051 without. The incidence was 4.9 per 1000 live births. Female sex (adjusted OR 7.2, 95% confidence interval [CI] 4.6-11.2), breech presentation (adjusted OR 24.3, 95% CI 13.1-44.9), positive family history (adjusted OR 15.9, 95% CI 11.0-22.9) and first or second pregnancy (adjusted OR 1.8, 95% CI 1.5-2.3) were confirmed as risk factors (p < 0.001). In addition, there was an increased risk with vaginal delivery (adjusted OR 2.7, 1.6-4.5, p < 0.001) and post-maturity (OR 1.7, 1.2-2.4, p < 0.002).

CONCLUSIONS

One in 200 children born within our region requires treatment for DDH. Using both established and novel risk factors, we can potentially calculate an individual child's risk. Our findings may contribute to the debate regarding selective versus universal ultrasound screening.

LEVEL OF EVIDENCE

Prognostic Study: Level 1.

Problems of seating and mobility encountered by children with developmental dysplasia of the hip

The parents of 11 children who were either undergoing or had undergone treatment for 'late-diagnosed' developmental dysplasia of the hip were surveyed by questionnaire to discover the problems associated with activities of daily living. Within this survey, special emphasis was placed on the problems of seating and mobility. The results of the analysis show that there was a deficiency in the equipment available to cope with children in splintage and plaster; there was a need for products to help in seating, particularly with regard to enhancing mobility. This pilot study confirmed the need for focused research to provide such products and a definitive study has now been undertaken.

The demographics of developmental hip dysplasia in the Midwestern United States (Indiana)

BACKGROUND

Today's society is much more mobile than in the past. This increased mobility has resulted in different marriage/parenting groups. We wished to study the demographics of developmental dysplasia of the hip (DDH) in our area and compare/contrast our findings with those in the literature and specifically look for new findings compared to previous studies.

METHODS

A retrospective review of all children with DDH from 2003 through 2012 was performed. The age at first visit, gestational age, pregnancy number, gender, race, and family history of DDH was collected. Statistical significance was a p-value < 0.05.

RESULTS

There were 424 children (363 girls, 61 boys). Ethnicity was White in 80.8 %, Hispanic in 13.8 %, Black in 4.0 %, and Indo-Malay and Indo-Mediterranean in 0.7 % each; 66.8 % were unilateral; 14.2 % had a positive family history. The average gestational age was 38.1 weeks; 94.4 % were full term. The child was vertex presentation in 67.6 % and breech in 32.4 %; 52.8 % were delivered vaginally and 47.2 % by Cesarean section. The child was the first-born in 48.3 %. When compared to the birth statistics of our state, there was a higher proportion of Whites and Hispanics with DDH, and a lower, but not inconsequential, proportion of Blacks (p = 0.0018).

CONCLUSION

Mixing of gene pools and infant carrying methods (lack of swaddling or marked abduction) occurring with societal change likely explains the higher than expected proportion of DDH amongst those of Hispanic ethnicity and a lower than expected, but not rare, proportion in those of African ancestry.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

Seasonal variation in children with developmental dysplasia of the hip

BACKGROUND

It has been postulated that developmental dysplasia of the hip (DDH) is more frequent in infants born in the winter months. It was the purpose of this study to ascertain if there was any seasonal variation in DDH at the author's institution and compare/contrast our results with those in the literature using rigorous mathematical fitting.

METHODS

All children with DDH treated at the author's institution from 1993 to 2012 were identified. The month of birth was recorded and temporal variation was analyzed using cosinor analysis. Similar data from the literature was analyzed.

RESULTS

There were 424 children (363 girls, 61 boys). An additional 22,936 children were added from the literature for a total of 23,360. Pearson's Chi-square test demonstrated a non-uniform distribution in the month of birth for both our 424 children as well as the combined literature series in both the Northern and Southern hemispheres. Cosinor analysis of the 424 children demonstrated double peaks in mid-March and mid-October. For the entire 23,360 children, no seasonal variation was observed in 2,205 (9.4 %), a single winter peak in 16,425 (70.3 %), a single summer peak in 1,280 (5.5 %), and double peaks in the spring and autumn in 3,450 (14.8 %).

CONCLUSIONS

This study partly supports the hypothesis of tight clothing/cold temperature as one factor in the etiology of DDH with the tighter clothing/swaddling increasing the risk of DDH. However ~20 % of the DDH births demonstrated a non-winter peak. The single summer and double spring/autumn peaks, as well as in those series where no seasonal variation was noted, refutes the cold winter clothing hypothesis. Perhaps these different patterns in seasonal variation represent the heterogeneity of the genetic factors in DDH interacting with external factors (temperature and clothing) and internal factors (metabolic). Further study will be required to understand these different patterns in DDH seasonal variation.

LEVEL OF EVIDENCE

IV-case series.

The epidemiology and demographics of hip dysplasia

The etiology of developmental dysplasia of the hip (DDH) is unknown. There are many insights, however, from epidemiologic/demographic information. A systematic medical literature review regarding DDH was performed. There is a predominance of left-sided (64.0%) and unilateral disease (63.4%). The incidence per 1000 live births ranges from 0.06 in Africans in Africa to 76.1 in Native Americans. There is significant variability in incidence within each racial group by geographic location. The incidence of clinical neonatal hip instability at birth ranges from 0.4 in Africans to 61.7 in Polish Caucasians. Predictors of DDH are breech presentation, positive family history, and gender (female). Children born premature, with low birth weights, or to multifetal pregnancies are somewhat protected from DDH. Certain HLA A, B, and D types demonstrate an increase in DDH. Chromosome 17q21 is strongly associated with DDH. Ligamentous laxity and abnormalities in collagen metabolism, estrogen metabolism, and pregnancy-associated pelvic instability are well-described associations with DDH. Many studies demonstrate an increase of DDH in the winter, both in the northern and southern hemispheres. Swaddling is strongly associated with DDH. Amniocentesis, premature labor, and massive radiation exposure may increase the risk of DDH. Associated conditions are congenital muscular torticollis and congenital foot deformities. The opposite hip is frequently abnormal when using rigorous radiographic assessments. The role of acetabular dysplasia and adult hip osteoarthritis is complex. Archeological studies demonstrate that the epidemiology of DDH may be changing.

The normal centre-edge angle of Wiberg in the Chinese population: a population-based cross-sectional study

This study was designed to provide normal reference values for the centre-edge angle of Wiberg in the Chinese population by measuring 1494 radiographs according to the criteria of Tönnis. The mean angle was 23.1 degrees (4.7 degrees to 46.4 degrees) in childhood (four to nine years), increasing to 28.9 degrees (6 degrees to 48 degrees) in adolescence (10 to 18 years) and reaching 32.8 degrees (13.7 degrees to 58.8 degrees) in adults. The angle was positively correlated with age, increasing by a mean of 0.78 degrees annually before adulthood and by 0.070 degrees annually in adults. A relative upward tendency after middle age might contribute to degenerative changes. No gender difference was discovered. The change in the angle with age was similar to that observed in other ethnic groups, showing moderate differences in the average of individual age groups, but the ethnic differences are not sufficient to explain the variation of incidence of developmental dysplasia of the hip in different races.

The prevalence of dislocation in developmental dysplasia of the hip in Britain over the past thousand years

BACKGROUND

The aim of this study is to determine whether dislocation in developmental dysplasia of the hip (DDH) is changing in prevalence over time. This would allow us to see if modern improvements in diet, health, and obstetric care had any effect upon the likelihood of developing DDH.

METHODS

The material used was a large medieval skeletal collection excavated from Britain (6580 hips). The cemetery was in use from approximately AD 1100 to 1530.

RESULTS

The prevalence in the medieval series was found to be 2.7 per 1000.

DISCUSSION

This prevalence was comparable with published clinical series from 20th century Britain, with no statistical difference found on chi2 test.

CONCLUSIONS

It is concluded that hip dislocation secondary to DDH does not seem to be changing significantly in prevalence over the centuries, despite improvements in many other aspects of health over this time.

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.

Breech presentation and tossing a coin: heads or tails

Through a retrospective review of our own materials and data from peer-reviewed journals, among medical entities a greater probability than 0.5 was not found for breech presentation. Submitting the occurrence of breech presentation to the classical laws of probability means that each fetus in breech presentation has its 'pair' in cephalic presentation. Among medical entities with a probability of less than 0.5 for breech presentation, the group of fetuses in cephalic presentation consist of two subgroups: (1) fetuses which are by chance in cephalic presentation and whose number is identical to the number of fetuses in breech presentation, (2) fetuses which are in cephalic presentation because of the postural development. Likewise, introducing a medical entity with a small number of cases does not allow a conclusion to be drawn about a relationship between that entity and breech presentation.

Clinical screening for developmental dysplasia of the hip in Northern Ireland

PROBLEM

The incidence of late diagnosed developmental dysplasia of the hip requiring surgery in Northern Ireland is high. The reported incidence was 1.14 per 1000 children born during 1983-7.

DESIGN

Comparative retrospective study.

BACKGROUND AND SETTING

Clinical screening programme in Northern Ireland. Key measure for improvement: Reduced rate of operative intervention in children with developmental dysplasia of the hip detected after 6 months of age.

STRATEGIES FOR CHANGE

Increased emphasis on staff training, introduction of a centralised nurse led clinic to improve access to orthopaedic surgeons, and increased use of ultrasonography.

EFFECTS OF CHANGE

The incidence of developmental dysplasia of the hip diagnosed after 6 months in children born between January 1991 and December 1997 fell to 0.59 per 1000, presumably due to improved early detection. Nevertheless, 29 (16%) of the affected hips were not diagnosed when the child was first referred in the first 3 months of life. In addition, for 27 affected hips in children diagnosed after the age of 6 months there was a known risk factor (family history or breech delivery).

LESSONS LEARNT

Improvements to screening processes can reduce late incidence of developmental dysplasia of the hip. Further steps to improve detection in children with known risk factors and rate of detection at first referral could reduce late presentation further.

Developmental dysplasia of the hip practice guideline: technical report. Committee on Quality Improvement, and Subcommittee on Developmental Dysplasia of the Hip

OBJECTIVE

To create a recommendation for pediatricians and other primary care providers about their role as screeners for detecting developmental dysplasia of the hip (DDH) in children.

PATIENTS

Theoretical cohorts of newborns.

METHOD

Model-based approach using decision analysis as the foundation. Components of the approach include the following:

PERSPECTIVE

Primary care provider.

OUTCOMES

DDH, avascular necrosis of the hip (AVN).

OPTIONS

Newborn screening by pediatric examination; orthopaedic examination; ultrasonographic examination; orthopaedic or ultrasonographic examination by risk factors. Intercurrent health supervision-based screening. PREFERENCES: 0 for bad outcomes, 1 for best outcomes.

MODEL

Influence diagram assessed by the Subcommittee and by the methodology team, with critical feedback from the Subcommittee. EVIDENCE SOURCES: Medline and EMBASE search of the research literature through June 1996. Hand search of sentinel journals from June 1996 through March 1997. Ancestor search of accepted articles. EVIDENCE QUALITY: Assessed on a custom subjective scale, based primarily on the fit of the evidence to the decision model.

RESULTS

After discussion, explicit modeling, and critique, an influence diagram of 31 nodes was created. The computer-based and the hand literature searches found 534 articles, 101 of which were reviewed by 2 or more readers. Ancestor searches of these yielded a further 17 articles for evidence abstraction. Articles came from around the globe, although primarily Europe, British Isles, Scandinavia, and their descendants. There were 5 controlled trials, each with a sample size less than 40. The remainder were case series. Evidence was available for 17 of the desired 30 probabilities. Evidence quality ranged primarily between one third and two thirds of the maximum attainable score (median: 10-21; interquartile range: 8-14). Based on the raw evidence and Bayesian hierarchical meta-analyses, our estimate for the incidence of DDH revealed by physical examination performed by pediatricians is 8.6 per 1000; for orthopaedic screening, 11.5; for ultrasonography, 25. The odds ratio for DDH, given breech delivery, is 5.5; for female sex, 4.1; for positive family history, 1.7, although this last factor is not statistically significant. Postneonatal cases of DDH were divided into mid-term (younger than 6 months of age) and late-term (older than 6 months of age). Our estimates for the mid-term rate for screening by pediatricians is 0.34/1000 children screened; for orthopaedists, 0.1; and for ultrasonography, 0.28. Our estimates for late-term DDH rates are 0.21/1000 newborns screened by pediatricians; 0.08, by orthopaedists; and 0.2 for ultrasonography. The rates of AVN for children referred before 6 months of age is estimated at 2.5/1000 infants referred. For those referred after 6 months of age, our estimate is 109/1000 referred infants. The decision model (reduced, based on available evidence) suggests that orthopaedic screening is optimal, but because orthopaedists in the published studies and in practice would differ, the supply of orthopaedists is relatively limited, and the difference between orthopaedists and pediatricians is statistically insignificant, we conclude that pediatric screening is to be recommended. The place of ultrasonography in the screening process remains to be defined because there are too few data about postneonatal diagnosis by ultrasonographic screening to permit definitive recommendations. These data could be used by others to refine the conclusions based on costs, parental preferences, or physician style. Areas for research are well defined by our model-based approach.

Developmental dysplasia of the hip: a new approach to incidence

OBJECTIVE

The controversy over the incidence of developmental dysplasia of the hip (DDH) stems mainly from an ambiguity of criteria for defining a genuinely pathologic neonatal hip. In this study, we evaluate an algorithm we devised for the treatment of DDH, for its ability to identify those neonatal hips which, if left untreated, would develop any kind of dysplasia and, therefore, are to be included in the determination of DDH incidence.

METHODS

Clinical and ultrasonographic examinations for DDH were performed on 18 060 consecutive neonatal hips at 1 to 3 days of life. Newborns with skeletal deformities, neurologic/muscular disorders, and neural tube defects were excluded. Hips that featured any type of sonographic pathology were reexamined at 2 or 6 weeks, depending on the severity of the findings. Only hips in which the initial pathology was not improved or had deteriorated were treated; all others were examined periodically until the age of 12 months.

RESULTS

Sonographic screening of 18 060 hips detected 1001 instances of deviation from normal, indicating a sonographic DDH incidence of 55.1 per 1000. However, only 90 hips remained abnormal and required treatment, indicating a true DDH incidence of 5 per 1000 hips. All the others evolved into normal hips, and no additional instances of DDH were found on follow-up throughout the 12 months.

CONCLUSIONS

The implementation of our protocol enables us to distinguish two categories of neonatal hip pathology: one that eventually develops into a normal hip (essentially sonographic DDH); and another that will deteriorate into a hip with some kind of dysplasia, including full dislocation (true DDH). This approach seems to allow for a better-founded definition of DDH, for an appropriate determination of its incidence, for decision-making regarding treatment, and for assessment of the cost-effectiveness of screening programs for the early detection of DDH.

Surgery for congenital dislocation of the hip in the UK as a measure of outcome of screening. MRC Working Party on Congenital Dislocation of the Hip. Medical Research Council

BACKGROUND

Universal clinical screening for congenital dislocation of the hip to detect hip instability in neonates was introduced in the UK as a national policy in 1969, but its effectiveness is not known. We aimed to assess the extent to which surgery for congenital dislocation of the hip is the result of a failure of detection through screening or follows non-surgical treatment after detection by screening.

METHODS

We established a national orthopaedic surveillance scheme and used routine hospital data for inpatients for 20% of births in the UK (Scotland and the Northern and Wessex regions) to ascertain the number of children aged under 5 years per 1000 livebirths who had received at least one operative procedure for congenital dislocation of the hip from April, 1993, to April, 1994. Estimates of the incidence of operative procedures were adjusted for under-ascertainment by capture-recapture techniques.

FINDINGS

The ascertainment-adjusted incidence of a first operative procedure for congenital dislocation of the hip in the UK was 0.78 per 1000 livebirths (95% CI 0.72-0-84). Congenital dislocation of the hip had not been detected by routine screening in 222 (70%) of 318 children reported to the national orthopaedic surveillance scheme. In 112 (35%) children the diagnosis was made primarily as a result of parental concern. 67 (21%) children had previously received non-surgical treatment. In Scotland and the Northern and Wessex regions, 81 cases were notified to the national orthopaedic surveillance scheme, 62 cases were identified only through routine hospital data on inpatients, and an estimated 20 cases were not identified by either source, making a total of 163 cases. Thus, 81 (50%) of these 163 cases were identified by surveillance, 125 (77%) by routine data, and 143 (88%) by both sources.

INTERPRETATION

The incidence of a first operative procedure for congenital dislocation of the hip in the UK was similar to that reported before screening was introduced. In most children who received surgery, congenital dislocation of the hip was not detected by screening. Formal evaluation of current and alternative screening policies, including universal primary ultrasound imaging, is needed.

A national survey of screening for congenital dislocation of the hip

OBJECTIVE

To identify current screening and management practices for congenital dislocation of the hip (CDH), and determine the extent to which ultrasound imaging of the hips is practised throughout the United Kingdom and the Irish Republic.

METHODS

Postal questionnaire to paediatricians responsible for the routine neonatal care of infants in all maternity units in the UK and the Irish Republic.

RESULTS

Questionnaires were returned for 254 maternity units (92% response rate). By 1994, 69% of maternity units had access to ultrasound imaging of the hips, compared to 14% in 1984. Ultrasound imaging of the hip was not used for universal primary screening, but in 93% of units was undertaken for further assessment of infants with clinically detected hip instability or those identified as being at high risk of CDH, or both. Clinical screening of newborn infants was performed by junior paediatricians, but training with a 'Baby Hippy' hip simulator model was provided in only 37% of units. Treatment of clinically detected hip instability, initiated by an orthopaedic surgeon in 93% of units, varied widely in type and duration.

CONCLUSIONS

Ultrasound imaging of the hip is increasingly used in the UK for secondary, rather than primary, screening. Current recommendations are implemented to a variable extent nationally, and the existing wide variation in screening and management for CDH reflects a lack of research evidence to support current screening practices. The effectiveness of screening for CDH needs to be established.

Evaluating the national screening programme for congenital dislocation of the hip

In 1969 universal clinical screening for neonatal hip instability was formally adopted in the United Kingdom with the aim of detecting and treating children considered to be at high risk of congenital dislocation of the hip (CDH). However, clinical screening is associated with both false positive and false negative diagnoses and has never been evaluated in a randomised trial. The emergence of hip ultrasound provides renewed impetus to reconsider and formally evaluate screening for CDH. Ultrasound imaging of the newborn hip may be used as a screening test and to assess and manage infants with clinically detected hip instability. Universal primary ultrasound screening has been adopted in some European countries, but enthusiasm for this new technology has been tempered by the subsequent large increases in treatment and follow up. This paper reviews the existing evidence to support the different approaches to screening and describes the research agenda of the MRC working party on congenital dislocation of the hip. A randomised trial of screening is required to evaluate the policy options before ultrasound screening becomes widely adopted within the United Kingdom. The feasibility and acceptability of a trial need to be explored and key issues relating to trial design addressed.