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

Molecular mechanisms and genetic factors contributing to the developmental dysplasia of the hip

The most prevalent hip disease in neonates is developmental dysplasia of the hip (DDH). A timely and accurate diagnosis is required to provide the most effective treatment for pediatric patients with DDH. Heredity and gene variation have been the subject of increased attention and research worldwide as one of the factors contributing to the pathogenesis of DDH. Genome-wide association studies (GWAS), genome-wide linkage analyses (GWLA), and exome sequencing (ES) have identified variants in numerous genes and single-nucleotide polymorphisms (SNPs) as being associated with susceptibility to DDH in sporadic and DDH family patients. Furthermore, the DDH phenotype can be observed in animal models that exhibit susceptibility genes or loci, including variants in CX3CR1, KANSL1, and GDF5. The dentification of noncoding RNAs and de novo gene variants in patients with DDH-related syndrome has enhanced our understanding of the genes implicated in DDH. This article reviews the most recent molecular mechanisms and genetic factors that contribute to DDH.

Incidence, Prevalence, Risk Factors, and Clinical Treatment for Children with Developmental Dysplasia of the Hip in Saudi Arabia. A Systematic Review

BACKGROUND

Developmental dysplasia of the hip (DDH) leads to pain, joint instability, and early degenerative joint disease. Incidence, prevalence, and management strategies of DDH have been well-documented in several countries, but not in Saudi Arabia.

OBJECTIVE

We synthesized the current evidence regarding incidence, prevalence, risk factors, and clinical treatment for children with DDH in Saudi Arabia.

METHODS

We searched 3 databases to locate studies. Studies that included children with DDH in Saudi Arabia; reported either incidence rate, prevalence, risk factors, and/or clinical practice; and were available in English or Arabic were included. We excluded reviews, case studies, or animal studies. Two independent authors reviewed potential studies and assessed study's quality.

RESULTS

Our search yielded 67 potential studies, of which 16 studies were included (total DDH sample = 3,127; age range = 2.5 to 86.4 months). Three studies reported incidence rates ranging from 3.1 to 4.9 per 1000 births, and 3 studies reported prevalence ranging from 6 to 78%. Nine studies reported that female sex, breech position, family history, and age less than 3 years were risk factors associated with DDH. Four studies reported that brace applications and closed reduction were conservative treatments, and 9 studies reported that open hip reduction, adductor tenotomy, and/or pelvic osteotomy were surgical approaches to treat DDH.

CONCLUSIONS

In Saudi Arabia, the Incidence and prevalence rates of DDH are 3.1 to 4.9 per 1,000 births, and 6-78%, respectively (differ from what has been reported in other countries), but the risk factors of DDH in Saudi Arabia appear to be similar in comparison to other countries (female, breech presentation, family history of DDH).

Bilateral Involvement in Developmental Dislocation of the Hip: Analysis of 561 Patients Operated on Using the Limited Posteromedial Approach

Our objective was to scrutinize the risk factors related to bilateral involvement in the developmental dysplasia of the hip (DDH) and to inspect the impact of bilaterality on the enduring results of the DDH. All patients, aged between 6 and 18 months, who underwent surgery using the limited posteromedial approach (734 hips from 561 patients), were included in this study. The number of births, birth type, history of consanguineous marriage, family history, and swaddling were analyzed. Physical examination and complaints of the patients were evaluated, and direct radiographs were examined in terms of the redislocation, avascular necrosis, and residual acetabular dysplasia. Among the 561 patients, bilateral DDH was observed in 173 patients (30.8%). The use of swaddling was found to be statistically significant between groups (p = 0.012). The use of swaddling for more than one month was associated with a higher odds ratio for bilaterality (p = 0.001, OR = 1.56, 95% CI: 1.2-2.0). Furthermore, bilaterality was associated with a higher risk for redislocation in DDH (p = 0.001, OR = 4.25, 95% CI: 1.6-11.2). The study concludes that swaddling for over a month is strongly linked with the bilateral involvement in DDH. It is important to note that bilaterality plays a crucial role in the development of redislocation after open reduction in DDH.

Are Abnormal Muscle Biomechanics and Patient-reported Outcomes Associated in Patients With Hip Dysplasia?

BACKGROUND

Developmental dysplasia of the hip (DDH) is a major risk factor for the early development of hip osteoarthritis. Recent studies have demonstrated how DDH alters hip muscle moment arms and elevates muscle-induced biomechanical variables such as joint reaction forces and acetabular edge loads. Understanding the link between abnormal biomechanics and patient-reported outcome measures (PROMs) is important for evidence-based clinical interventions that improve patient symptoms and functional outcomes. To our knowledge, there are no reports of the relationships between muscle-induced biomechanics and PROMs.

QUESTIONS/PURPOSES

(1) Are there associations between PROMs and muscle-induced hip biomechanics during gait for patients with DDH and controls? (2) Are there associations among PROMs and separately among biomechanical variables?

METHODS

Participants in this prospective cross-sectional comparative study included 20 female patients with DDH who had no prior surgery or osteoarthritis and 15 female individuals with no evidence of hip pathology (controls) (age: median 23 years [range 16 to 39 years]; BMI: median 22 kg/m 2 [range 17 to 27 kg/m 2 ]). Muscle-induced biomechanical variables for this cohort were reported and had been calculated from patient-specific musculoskeletal models, motion data, and MRI. Biomechanical variables included joint reaction forces, acetabular edge loads, hip center lateralization, and gluteus medius muscle moment arm lengths. PROMs included the Hip Disability and Osteoarthritis Outcome Score (HOOS), the WOMAC, International Hip Outcome Tool-12, National Institutes of Health Patient-Reported Outcome Measure Information System (PROMIS) Pain Interference and Physical Function subscales, and University of California Los Angeles activity scale. Associations between PROMs and biomechanical variables were tested using Spearman rank-order correlations and corrected for multiple comparisons using the Benjamini-Yekutieli method. For this study, associations between variables were considered to exist when correlations were statistically significant (p < 0.05) and were either strong (ρ ≥ 0.60) or moderate (ρ = 0.40 to 0.59).

RESULTS

Acetabular edge load impulses (the cumulative acetabular edge load across the gait cycle), medially directed joint reaction forces, and hip center lateralization most commonly demonstrated moderate or strong associations with PROMs. The strongest associations were a negative correlation between acetabular edge load impulse on the superior acetabulum and the HOOS function in daily living subscale (ρ = -0.63; p = 0.001), followed by a negative correlation between hip center lateralization and the HOOS pain subscale (ρ = -0.6; p = 0.003), and a positive correlation between hip center lateralization and the PROMIS pain subscale (ρ = 0.62; p = 0.002). The University of California Los Angeles activity scale was the only PROM that did not demonstrate associations with any biomechanical variable. All PROMs, aside from the University of California Los Angeles activity scale, were associated with one another. Although most of the biomechanical variables were associated with one another, these relationships were not as consistent as those among PROMs.

CONCLUSION

The associations with PROMs detected in the current study suggest that muscle-induced biomechanics may have wide-reaching effects not only on loads within the hip, but also on patients' perceptions of their health and function. As the treatment of DDH evolves, patient-specific joint preservation strategies may benefit from targeting the underlying causes of biomechanical outcomes associated with PROMs.

LEVEL OF EVIDENCE

Level III, prognostic study.

Postsurgical Analysis of Gait, Radiological, and Functional Outcomes in Children with Developmental Dysplasia of the Hip

BACKGROUND

Children undergoing DDH correction surgery may experience gait abnormalities following soft tissue releases and bony procedures. The purpose of this study was to compare the residual gait changes, radiological outcomes, and functional outcomes in children who underwent DDH surgery with those in healthy controls.

METHODS

Inertial motion sensors were used to record the gait of 14 children with DDH and 14 healthy children. Pelvic X-ray was performed to determine the Severin classification and the presence of femoral head osteonecrosis (Bucholz-Odgen classification). For functional evaluation, the Children's Hospital Oakland Hip Evaluation Scale (CHOHES) was used.

RESULTS

There was no difference in spatial parameters between the two groups. In terms of temporal parameters, the DDH-affected limbs had a shorter stance phase (p < 0.001) and a longer swing phase (p < 0.001) than the control group. The kinematic study showed that the affected limb group had smaller hip adduction angle (p = 0.002) and increased internal rotation (p = 0.006) with reduced upward pelvic tilt (p = 0.020). Osteonecrosis was graded II, III, and IV in five, three, and one patients, respectively. Five patients had no AVN changes. The Severin classification was grade I, II, and III for six, three, and five patients, respectively. Most patients had good functional outcomes on the CHOHES, with a mean total score of 96.64 ± 5.719. Multivariate regression analysis revealed that weight, height, and femoral osteotomy were independent predictors for gait, radiological and functional outcome.

CONCLUSION

Despite good functional scores overall, some children had poor radiological outcomes and gait abnormalities. Our results identified the risk factors for poor outcomes, and we recommend specified rehabilitative strategies for long-term management.

Risk factors of developmental dysplasia of the hip in a single clinical center

Developmental dysplasia of the hip (DDH) is the main cause of early-onset hip osteoarthritis in adulthood. Early screening of DDH is the key to avoiding these severe complications. This study aimed to assure the risk factors are suitable for screening patients with DDH in our region. We retrospectively analyzed 10,668 patients (21,336 hips) at our hospital. Overall, 204 patients with pathological DDH and 408 patients with normal hips were included in this study. All patients were diagnosed by performing ultrasound examinations according to the Graf technique. The risk factors were assessed based on patients' clinical data. Pearson's chi-square or Fisher's exact tests and multivariate logistic regression analysis were performed for statistical analysis. A total of 204 patients were diagnosed with pathologic DDH and were treated with the Pavlik harness. Among these, 184 patients were female. There were 73 cases of first birth, 13 had oligohydramnios, 13 had foot deformity, 31 had breech delivery, 6 had congenital muscular torticollis. Female sex, vaginal delivery, breech presentation, oligohydramnios and foot deformity were identified as the risk factors for DDH. The risk factors of DDH in our clinical center were confirmed in our clinical center, this can supply the screening advice for the doctors.

Knowledge and Practices Related to Hip-Healthy Swaddling for Newborns Among Maternity Nurses

OBJECTIVE

To assess the self-reported knowledge, education, and practices related to hip-healthy swaddling of newborns among nurses, how they teach this technique to parents, and the relationships among these factors.

DESIGN

Descriptive cross-sectional exploratory survey.

SETTING

Academic women and children's hospital with an average of 4,500 annual births.

PARTICIPANTS

One hundred four registered maternity nurses who work primarily in the maternity unit.

METHODS

At three staff meetings, we surveyed maternity nurses to determine their knowledge, education, and practices related to hip-healthy swaddling and how they teach this technique to parents. We analyzed results using descriptive statistics and chi-square and Fisher's exact tests.

RESULTS

Of the 156 nurses in the maternity unit, 104 attended three staff meetings and completed the survey. Among the participants, 18.9% (18/95; 9 participants did not respond) were unable to identify the correct hip swaddling position. Overall, 64.2% (61/95; 9 participants did not respond) reported that they received education on general swaddling technique, yet 14.8% (9/61) of these participants were unable to identify the correct hip-healthy swaddling position. Among the participants, 99.0% (103/104) reported that nurses teach parents how to swaddle infants rather than other health care providers; 12.5% (13/104) of participants responded that medical doctors provide training as well. Overall, 67.0% (69/103; 1 participant did not respond) reported that they taught parents in >75% of parent interactions.

CONCLUSION

Our results illustrate a gap in knowledge about hip-healthy swaddling among the maternity nurses who participated in this survey and a need for further education.

Investigation on the etiology of patients undergoing non-traumatic total hip arthroplasty in China

BACKGROUND

China has neither a nationwide joint replacement registry similar to Sweden and New Zealand nor a universal healthcare (medical insurance) registry similar to Hong Kong and Singapore to check. The purpose was to initially understand the distribution characteristics of gender, age and etiology of patients undergoing total hip replacement for non-traumatic reasons nationwide.

METHODS

The clinical data of patients who underwent initial artificial total hip replacement due to non-traumatic reasons in joint surgery of 13 large general first-class hospitals at Grade 3 in northern, western, eastern, southern, and southwestern China were collected. After the classification of patients by gender, the etiological characteristics and age distribution of male and female patients were compared, as well as male to female ratio and disease composition ratio of patients of different ages, distribution of causes in different regions, composition ratio, and age distribution characteristics of patients of different ethnic groups.

RESULTS

In this study, the data of a total of 7663 patients in joint surgery of 13 general first-class hospitals at Grade 3 from 2015 to 2017 were collected, and 7622 patients were finally included in the study after excluding missing age, gender and some foreign patients. The main causes of diagnosis in male patients were AVN, DDH, and OA, and top 3 causes in female patients were DDH, AVN, and OA.

CONCLUSIONS

This study initially understand the distribution characteristics of gender, age and etiology of patients undergoing total hip replacement for non-traumatic reasons nationwide, and further guide the clinical diagnosis, early prevention and treatment of the disease and provide data.

Back-Carrying in Children Is Related to Lower Limb Development

Back-carrying of children is a culturally accepted method of transport and safekeeping of babies in many cultures. Developmental consequences related to back-carrying practices have not been directly investigated. This study determined the relationship between frontal and transverse plane lower limb (LL) development, and back-carrying practices, in black Setswana-speaking children. In 691 2- to 9-year-old Setswana-speaking children, the tibiofemoral angle, intermalleolar distance, femoral anteversion angle (AVA) and tibial torsion angle (TTA), were measured to determine LL development. Back-carrying practices were recorded with a questionnaire and Classification and Regression Tree (CART) was used for the analyses. Significant (p < 0.001) relationships, between back-carrying practices and LL development, were discovered. Statistically significant greater genu valgum (F(5, 690) = 7.2, p < 0.001), greater internal TTAs (F(9, 684) = 17.8, p < 0.001), and smaller AVAs (F(13, 685) = 5.1, p < 0.001) were observed in children back-carried more frequently than children back-carried less frequently. There are relationships between back-carrying practices and LL development in both the frontal and transverse plane. However, the genu valgum, internal TTA and smaller AVA noted in more frequently back-carried children is still within normal limits, thus no educational intervention in back-carrying methods or durations is required. Further research should determine the exact back-carrying practice factors (age until which the child is back-carried) impacting lower limb development the greatest.

Genetic Study of IL6, GDF5 and PAPPA2 in Association with Developmental Dysplasia of the Hip

Background: Developmental dysplasia of the hip (DDH) is one of the most prevalent skeletal disorders. DDH is considered a pathologic condition with polygenic background, but environmental and mechanic factors significantly contribute to its multifactorial etiology. Inheritance consistent with autosomal dominant type has also been observed. Single-nucleotide polymorphisms (SNPs) in various genes mostly related to formation of connective tissue are studied for a possible association with DDH. Methods: We genotyped three SNPs, rs1800796 located in the promoter region of the IL6 gene, rs143383 located in the 5′ untranslated region (UTR) of the GDF5 gene and rs726252 located in the fifth intron of the PAPPA2 gene. The study consisted of 45 subjects with DDH and 85 controls from all regions of Slovakia. Results: Association between DDH occurrence and studied genotypes affected by aforementioned polymorphisms was confirmed in the case of rs143383 in the GDF5 gene (p = 0.047), where the T allele was over-expressed in the study group. Meanwhile, in the matter of IL6 and PAPPA2, we found no association with DDH (p = 0.363 and p = 0.478, respectively). Conclusions: These results suggest that there is an association between DDH and GDF5 polymorphisms and that the T allele is more frequently presents in patients suffering from DDH.

Genetics of developmental dysplasia of the hip

In the last decade, the advances in the molecular analyses and sequencing techniques allowed researchers to study developmental dysplasia of the hip (DDH) more thoroughly. Certain chromosomes, genes, loci and polymorphisms are being associated with variable severity of this disorder. The wide range of signs and symptoms is dependent either on isolated or systemic manifestation. Phenotypes of isolated cases range from only a mild ligamental laxity, through subluxation, to a complete dislocation of the femoral head. Systemic manifestation is connected to various forms of skeletal dysplasia and other malformations characterized by significant genetic aberrations. To reveal the background of DDH heredity, multiple studies focused on large sample sizes with an emphasis on the correlation between genotype, phenotype and continuous clinical examination. Etiological risk factors that have been observed and documented in patients include genetic, environmental, and mechanical factors, which significantly contribute to the familial or nonfamilial occurrence and phenotypic variability of this disorder. Still, the multifactorial etiology and pathogenesis of DDH are not yet sufficiently clarified, explained, or understood. Formation of connective tissue, osteogenesis, chondrogenesis, and all other affected pathways and variations in the function of their individual elements contribute to the creation of the pathology in a developing human body. This review article presents an up-to-date list of known DDH associated genes, their products, and functional characteristics.

Developmental Dysplasia of the Hip: A Review of Etiopathogenesis, Risk Factors, and Genetic Aspects

As one of the most frequent skeletal anomalies, developmental dysplasia of the hip (DDH) is characterized by a considerable range of pathology, from minor laxity of ligaments in the hip joint to complete luxation. Multifactorial etiology, of which the candidate genes have been studied the most, poses a challenge in understanding this disorder. Candidate gene association studies (CGASs) along with genome-wide association studies (GWASs) and genome-wide linkage analyses (GWLAs) have found numerous genes and loci with susceptible DDH association. Studies put major importance on candidate genes associated with the formation of connective tissue (COL1A1), osteogenesis (PAPPA2, GDF5), chondrogenesis (UQCC1, ASPN) and cell growth, proliferation and differentiation (TGFB1). Recent studies show that epigenetic factors, such as DNA methylation affect gene expression and therefore could play an important role in DDH pathogenesis. This paper reviews all existing risk factors affecting DDH incidence, along with candidate genes associated with genetic or epigenetic etiology of DDH in various studies.

Profile of Patients Diagnosed with Developmental Dysplasia of the Hip

Objective  To describe the profile of patients with developmental dysplasia of the hip (DDH) diagnosed by physical and ultrasound examination, with the implementation of a protocol for the treatment and follow-up of DDH.

Methods  A cross-sectional study with DDH patients born between January 2014 and December 2016, in the city of Pelotas, Southern Brazil. Ethnicity, gender, birth weight, fetal presentation, affected side of the hip, gestational age, maternal age and family history were considered. The data on the medical records were compared with the characteristics of the general population described on the Brazilian National Information System on Live Births (Sistema de Informação sobre Nascidos Vivos [SINASC]).

Results  A total of 33 DDH patients were identified, mostly female, with a four-fold higher probability of having the condition ( p  < 0.001); the left was the most affected side. No statistically significant association was found regarding the following factors: birth weight, gestational age, ethnicity, and maternal age. The newborns in breech presentation had a 15-fold higher probability of presenting DDH ( p  < 0.001). A total of 21 newborns required immediate treatment of the hips, since the ultrasound showed a Graf classification of IIb or higher, or the radiography showed dislocation in DDH patients older than 6 months of age.

Conclusion  Screening for DDH is essential in all newborns; physical examinations revealing alterations must be complemented with ultrasound imaging to avoid the delayed diagnosis of the condition.

Association between periacetabular osteotomy and hip dysplasia among relatives: a cross-sectional study

INTRODUCTION

Previous studies indicate a familial predisposition for developmental dysplasia of the hip (DDH), especially among first-degree relatives. This study investigated the association between unilateral or bilateral periacetabular osteotomy (PAO), family history of DDH and the degree of relationship with relatives with DDH.

MATERIAL AND METHODS

This cross-sectional study consisted of 815 consecutive patients undergoing PAO from 1998 to 2016. Information regarding unilateral or bilateral PAO, gender and age at the time of surgery was obtained from the clinical PAO database at Aarhus University Hospital, Denmark. A questionnaire was used to collect information about the family history of DDH. The association was assessed by logistic regression analysis, and divided into 615 unilateral and 200 bilateral PAO patients.

RESULTS

PAO patients with a first-degree relative with DDH had a 72% (odds ratio [OR] = 1.72, 95% confidence interval [CI] 1.17; 2.50) higher occurrence of bilateral PAO than patients without family relatives with DDH. This association was statistically significant (p = 0.005), even when adjusting for gender and age at the time of surgery. A similar association was not demonstrated among any other degrees of relationship.

CONCLUSION

Danish patients with DDH and a first-degree relative with DDH have an increased risk of being surgically treated with bilateral PAO compared to patients without a family history of DDH. Patients undergoing bilateral PAO may therefore have a strong genetic predisposition for DDH. This study reveals a potential group of patients with DDH where genetic analysis may identify relatives with a higher risk of the disease.

Operative Reduction for Developmental Dysplasia of the Hip: Epidemiology Over 16 Years

BACKGROUND

The burden of surgical treatment for infantile developmental dysplasia of the hip (DDH) is unknown. We aimed to investigate the epidemiology of operative DDH reductions in the United States and identify potential at-risk populations.

METHODS

The Healthcare Utilization Project Kids' Inpatient Database (1997 to 2012) were analyzed. International Classification of Diseases (ICD-9) codes identified inpatient hospitalizations for DDH reductions excluding neuromuscular cases. Hospital variables and patient demographics were captured. Weighted population-level counts were calculated to allow for national estimates.

RESULTS

An estimated 5525 (95% confidence interval, 4907.8-6142.2) operative reductions were performed. In total, 73.3% were open with a mean age at the reduction of 2.3 years (95% confidence interval, 2.1-2.5). In total, 70.0% were female and 42.3% were white. Regional distribution varied: 36.4% of reductions occurred in the West, 22.8% in the South, 21.9% in the Midwest, and 18.9% in the Northeast. Operative reductions decreased over time; open reductions decreased by 5.6% and closed by 53.4%. Mean age at treatment increased from 1.6 to 3.7 years (P<0.001). On multivariate analysis, age (P<0.001) and geographic location (P<0.05) were associated with open reduction. Patients in the West had increased odds of being Hispanic or Asian/Pacific Islander [odds ratio (OR), 4.9, P<0.001 and OR, 2.8; P=0.008]. In the South and Midwest, the highest income quartile was protective (OR, 0.4; P=0.001 and OR, 0.5; P=0.018).

CONCLUSIONS

The frequency of closed reductions decreased more over time compared with open reductions. However, the mean age of children undergoing reductions increased suggesting a possible delay in diagnosis. The data suggests that there is room for improvement in screening. Targeted research in identified populations may reduce the burden of surgical disease in infantile DDH.

LEVEL OF EVIDENCE

Level III.

A novel iterative mixed model to remap three complex orthopedic traits in dogs

Hip dysplasia (HD), elbow dysplasia (ED), and rupture of the cranial (anterior) cruciate ligament (RCCL) are the most common complex orthopedic traits of dogs and all result in debilitating osteoarthritis. We reanalyzed previously reported data: the Norberg angle (a quantitative measure of HD) in 921 dogs, ED in 113 cases and 633 controls, and RCCL in 271 cases and 399 controls and their genotypes at ~185,000 single nucleotide polymorphisms. A novel fixed and random model with a circulating probability unification (FarmCPU) function, with marker-based principal components and a kinship matrix to correct for population stratification, was used. A Bonferroni correction at p<0.01 resulted in a P< 6.96 ×10-8. Six loci were identified; three for HD and three for RCCL. An associated locus at CFA28:34,369,342 for HD was described previously in the same dogs using a conventional mixed model. No loci were identified for RCCL in the previous report but the two loci for ED in the previous report did not reach genome-wide significance using the FarmCPU model. These results were supported by simulation which demonstrated that the FarmCPU held no power advantage over the linear mixed model for the ED sample but provided additional power for the HD and RCCL samples. Candidate genes for HD and RCCL are discussed. When using FarmCPU software, we recommend a resampling test, that a positive control be used to determine the optimum pseudo quantitative trait nucleotide-based covariate structure of the model, and a negative control be used consisting of permutation testing and the identical resampling test as for the non-permuted phenotypes.

Late-presenting developmental dysplasia of the hip in Jordanian males. A retrospective hospital based study

Objectives:

To describe the pattern of developmental dysplasia of the hip (DDH) in late presenting Jordanian male patients and identify the risk factors and associated findings.

Methods:

This is a retrospective study of 1145 male patients who attended the Pediatric Orthopedic Clinic for a DDH check up. This study was carried out in the Orthopedic Section, Special Surgery Department, Faculty of Medicine, The University of Jordan, Amman, Jordan between March 2011 and October 2014. Data was collected from medical records, and x-ray measurements were evaluated.

Results:

Of the 1145 male patients, 43 (3.75%) with 70 involved hips were diagnosed with late- presenting DDH. Being a first-born baby resulted in 41.9% increased risk for DDH. Cesarian delivery was significantly associated with an increased risk of hip dislocation (p=0.004) while normal delivery was significantly associated with acetabular dysplasia (p=0.004). No predictable risk factors were found in 44.2% patients with DDH. Bilateral cases were more common than unilateral cases: (26 [60.5%] versus 17 [39.5%]). Limited abduction was a constant finding in all dislocated hips (p<0.001). Associated conditions, such as club foot and congenital muscular torticollis were not observed.

Conclusion:

Cesarian section is a significant risk for dislocated hips while normal delivery is significantly associated with acetabular dysplasia. Bilateral DDH is more common than the unilateral. Club foot and torticollis were not observed in this series.