Screening for congenital dislocation of the hip by child-health nurses in Western Australia

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.

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.

Clinical practice guideline: early detection of developmental dysplasia of the hip. Committee on Quality Improvement, Subcommittee on Developmental Dysplasia of the Hip. American Academy of Pediatrics

Developmental dysplasia of the hip is the preferred term to describe the condition in which the femoral head has an abnormal relationship to the acetabulum. Developmental dysplasia of the hip includes frank dislocation (luxation), partial dislocation (subluxation), instability wherein the femoral head comes in and out of the socket, and an array of radiographic abnormalities that reflect inadequate formation of the acetabulum. Because many of these findings may not be present at birth, the term developmental more accurately reflects the biologic features than does the term congenital. The disorder is uncommon. The earlier a dislocated hip is detected, the simpler and more effective is the treatment. Despite newborn screening programs, dislocated hips continue to be diagnosed later in infancy and childhood,(1-11) in some instances delaying appropriate therapy and leading to a substantial number of malpractice claims. The objective of this guideline is to reduce the number of dislocated hips detected later in infancy and childhood. The target audience is the primary care provider. The target patient is the healthy newborn up to 18 months of age, excluding those with neuromuscular disorders, myelodysplasia, or arthrogryposis.

Decline in the incidence of late diagnosed congenital dislocation of the hip

INTRODUCTION

We reviewed the incidence of early and late diagnosed CDH over a 13 yr period in a single maternity with a well established follow-up program and a stable population base. In March 1991, all newborn infants were nursed in the lateral or supine position, having previously been nursed prone. In addition, a dedicated hip screener was appointed in October 1992. We wished to determine whether these changes could have led to a reduction in late diagnosed CDH.

METHODS

Babies with suspected CDH were seen by a single consultant orthopaedic surgeon within 1 week of birth. Splints were not applied until diagnosis was confirmed by the orthopaedic surgeon. The study period was from January 1983 to December 1995, inclusive.

RESULTS

37,383 babies were born during the study period, an average of 2,876 births per annum. The average rate of babies referred to the orthopaedic surgeon was 12.8 per 1,000 (range 5.5-28.2 per 1,000). The average incidence of babies splinted early was 7.19 per 1,000 (range 4.0-14.1 per 1,000) with no discernible increase or decrease over the yrs. In contrast, there was a clear reduction in the incidence of late diagnosed CDH; 42/24,713 births (January 1983-February 1992) compared to only 2/12,673 births (March 1992-December 1995; p < 0.0001. Twelve of the 44 infants (27 per cent) diagnosed with late diagnosed CDH were discovered by the policy of routine hip radiographs at 6 months of age of all babies born by breech presentation (2/12) or those with a positive family history of CDH in a first degree relative (10/12). Six others had a diagnosis of CDH confirmed by X-rays done at 6 months of age because of doubts about their examination in the newborn period.

CONCLUSIONS

Nursing infants in the supine or lateral position and the introduction of a single hip screener were associated with a reduction in the incidence of late diagnosed CDH. Routine hip radiographs of high risk infants at 6 months of age proved to be a valuable safety net in detecting a significant proportion of previously undetected infants with CDH.