A case-control study of congenital hip dislocation

To swaddle, or not to swaddle? Paleoepidemiology of developmental dysplasia of the hip and the swaddling dilemma among the indigenous populations of North America

OBJECTIVES

Clinical prevalence of developmental dysplasia of the hip (DDH) is high among modern indigenous populations of North America, yet no systematic study of the paleoepidemiology of this group exists. This study discusses the skeletal criteria, epidemiology, pathophysiology, and risk factors of DDH. A range of cases of DDH from an archaeological Native American population are described and the clinical and prehistoric prevalence of DDH among indigenous populations of North America are calculated and discussed within a biocultural perspective.

METHODS

Pelves of 390 adults from the Late Prehistoric (1490 B.P. ± 70) Buffalo site, West Virginia, were examined for DDH. Morphology of true and false acetabula was classified and other changes of the pelvis, lower limb, and spine were noted along with cranial deformation, providing evidence of infant restriction. Prevalence of DDH among living and archaeological indigenous peoples of North America were calculated and compared. Cranial deformation was assessed as evidence for swaddling.

RESULTS

DDH was identified in 18 adults from Buffalo, resulting in a minimum prevalence of 46.15 per 1,000, within the range reported in modern indigenous groups in North America. Most, but not all, of the DDH cases were associated with cranial deformation, but not all cases of cranial deformation were associated with DDH.

CONCLUSIONS

The etiology of DDH suggests that components of both genetic predisposition and swaddling practices have combined to create a high-risk environment for the development of DDH, contributing to high prevalence within archaeological populations, like Buffalo, and modern Indigenous groups of North America.

Joined at the hip? A paleoepidemiological study of developmental dysplasia of the hip and its relation to swaddling practices among indigenous peoples of North America

OBJECTIVES

Clinical prevalence of developmental dysplasia of the hip (DDH) is the highest among modern indigenous populations of North America, yet no systematic study of the paleoepidemiology of this group exists. This study discusses the skeletal criteria, epidemiology, pathophysiology, and risk factors for DDH. A range of cases of DDH from an archaeological Native American population are described, and the clinical and prehistoric prevalence of DDH among indigenous populations of North America are calculated and discussed within a biocultural perspective.

METHODS

Pelves of 390 adults from the Late Prehistoric (1490 BP ± 70) Buffalo site, West Virginia were examined for DDH. Morphology of true and false acetabula was classified and other changes of the pelvis, lower limb, and spine were noted along with cranial deformation, providing evidence of infant restriction. Prevalence of DDH among living and archaeological indigenous peoples of North America were calculated and compared.

RESULTS

DDH was identified in eighteen adults from Buffalo, resulting in a prevalence of 46.15, within the range reported in modern indigenous groups in North America. However, there is a significant difference between the DDH prevalence in prehistory and today in the target population.

CONCLUSIONS

Indigenous peoples of North America have the highest reported global prevalence of DDH today and in prehistory. The etiology of DDH suggests that components of both genetic predisposition and swaddling practices have combined to create a high-risk environment for the development of DDH, contributing to its high prevalence within archaeological populations, like Buffalo, and modern Native American/Aboriginal groups within North America.

Risk factors for developmental dysplasia of the hip: a meta-analysis

Early detection and subsequent treatment of developmental dysplasia of the hip (DDH) is thought to improve its prognosis. Frequently reported risk factors for DDH are a positive family history of DDH, female sex and breech presentation, but there is not a lot of systematic knowledge about DDH risk factors. We performed a systematic review and meta-analysis of the available evidence on DDH risk factors. We searched Medline, EMBASE and The Cochrane Library from conception up until October 2011 for primary articles on the subject. All studies reporting on potential risk factors for DDH that allowed construction of a two-by-two table were selected. Language restrictions were not applied. Two reviewers independently selected studies, extracted data and assessed study quality. The association between risk factors and DDH was expressed as a common odds ratio (OR) with a 95% confidence interval (CI). We identified 30 relevant studies reporting on 1,494,387 children; 26 studies were cohort studies and four studies used a case-control design. The risk of DDH was strongly increased in case of breech delivery (OR 5.7, 95% CI 4.4-7.4), female sex (OR 3.8, 95% CI 3.0-4.6) a positive family history of DDH (OR 4.8, 95% CI 2.8-8.2) and clicking hips at clinical examination (OR 8.6, 95% CI 4.5-16.6). This meta-analysis shows that infants born in breech presentation, female infants, infants with a positive family history and clicking hips at clinical examination have an increased risk for DDH. This knowledge can be helpful in the development of screening programs for DDH.

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.

Perinatal risk factors for developmental dysplasia of the hip

AIMS

To identify perinatal risk factors for developmental dysplasia of the hip (DDH) and define the risk for each factor.

METHODS

In this case control study, using logistic regression analysis, all 1127 cases of isolated DDH live born in South Australia in 1986-93 and notified to the South Australian Birth Defects Register were included; controls comprised 150130 live births in South Australia during the same period without any notified congenital abnormalities.

RESULTS

Breech presentation, oligohydramnios, female sex and primiparity were confirmed as risk factors for DDH. Significant findings were an increased risk for vaginal delivery over caesarean section for breech presentation (as well as an increased risk for emergency section over elective section), high birthweight (> or = 4000 g), postmaturity and older maternal age; multiple births and preterm births had a reduced risk. There was no increased risk for caesarean section in the absence of breech presentation. For breech presentation, the risk of DDH was estimated to be at least 2.7% for girls and 0.8% for boys; a combination of factors increased the risk.

CONCLUSIONS

It is suggested that the risk factors identified be used as indications for repeat screening at 6 weeks of age and whenever possible in infancy. Other indications are family history and associated abnormalities.