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.

https://downloads.hindawi.com/archive/2011/238607.pdf

The Epidemiology and Demographics of Hip Dysplasia

OBJECTIVE--To estimate the proportion of preventable congenital abnormalities in Hungary. DESIGN--Analysis of available Hungarian data-bases and of the effectiveness of primary, secondary, and tertiary preventive methods. SETTING--Databases of ad hoc epidemiological studies and of the Hungarian congenital abnormality registry. MAIN OUTCOME MEASURES--Prevalence at birth and prevalence after prevention in 73 congenital abnormality types or groups. RESULTS--Preventive methods are available for 51 (70%) of the 73 congenital abnormality types or groups evaluated. The birth prevalence of all congenital abnormalities could be reduced from 65 to 26 per 1000; thus 39 per 1000 (60%) are preventable. Without congenital dislocation of the hip, which is unusually common in Hungary, the preventable proportion of congenital abnormalities is 52%. CONCLUSION--Many congenital abnormalities can be prevented, but as they do not represent a single pathological category there is no single strategy for their prevention.

https://www.bmj.com/content/bmj/306/6876/499.full.pdf

What proportion of congenital abnormalities can be prevented

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 150 130 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 (⩾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.

https://fn.bmj.com/content/fetalneonatal/76/2/F94.full.pdf

Perinatal risk factors for developmental dysplasia of the hip

Introduction
Congenital dysplasia of the hip is an abnormal seating of the femoral head in the acetabulum, mainly caused by shallow acetabulum and lax joint capsule. Genetic factors play a considerable role in the pathogenesis of congenital dysplasia of the hip. The gene growth differentiate factor 5 (GDF5) has been implicated in skeletal development and joint morphogenesis in humans and mice. A functional single nucleotide polymorphism (SNP) in the 5'-untranslated region of GDF5 (rs143383) was reported to be associated with osteoarthritis susceptibility. As a key regulator in morphogenesis of skeletal components and soft tissues in and around the joints, GDF5 may be involved in the aetiology and pathogenesis of congenital dysplasia of the hip. Our objective is to evaluate if the GDF5 SNP is associated with congenital dysplasia of the hip in people of Han Chinese origin.

/pdf/association-of-a-single-nucleotide-polymorphism-in-growth-c7tgntv0op.pdf

Association of a single nucleotide polymorphism in growth differentiate factor 5 with congenital dysplasia of the hip: a case-control study

Only during the past 10 years has it been generally appreciated that congenital dislocation of the hip (CDH) can be found in the newborn child if looked for specifically within the first few days of life. Befor this, diagnosis was usually made only after the child started to walk. During the past decade there has been at least a fourfold increase in the number of infants attending for treatment. Previous epidemiological and genetic studies have mostly not included the group with neonatal diagnosis. There is, in fact, no certainty that they are both of the same aetiology, and the present survey was undertaken with the object of studying neonatal CDH (diagnosed during the first 4 weeks of life, usually in the first week) and late-diagnosis CDH (diagnosed after the first 4 weeks, usually many months or years later). Only primary congenital dislocation is considered here, not cases associated with arthrogryposis or paralytic dislocation secondary to spina bifida and cerebral palsy. An attempt has been made to establish the incidence, and to determine the family aggregation of cases, parental age, birth order, pregnancy history, season of birth, and social class. In addition, an investigation relating to familial joint laxity and to acetabular dysplasia in CDH has been carried out, but these clinical findings will only be summarized here and details reported in another paper.

https://jmg.bmj.com/content/jmedgenet/7/4/315.full.pdf

J H Koehn

Papers

Congenital hip disease in Utah: the influence of genetic and nongenetic factors.