新生儿及婴儿发育性髋关节异常早期筛查及早期治疗的探讨

目的通过对新生儿及婴儿发育性髋关节异常的早期筛查,结合临床检查与超声检查诊断的评价,推动新生儿及婴儿发育性髋关节异常的早期诊治。方法对本院出生的1213例新生儿及866例年龄6个月以下婴儿进行临床及超声早期筛查（Graf方法）,以明确诊断,及时治疗。结果新生儿早期疑诊45例,最终确诊5例,婴儿确诊3例,经用Pavlik吊带治疗6例痊愈,1例6个月后行闭合复位石膏固定治疗。结论新生儿期超声检查髋关节不稳定率偏高（Graflla型髋）,发育性髋关节异常的早期筛查,特别是低于6个月的超声检查检出率高,各科医师合作有利于DDH的早期诊治。     

Fr��herkennung der H��ftdysplasie

Background

Ultrasound screening is more sensitive for developmental dysplasia of the hip than clinical examination, but we do not know which form of ultrasound screening is the best.

Patients and methods

A retrospective analysis was performed of ultrasonographic findings of an universal ultrasound screening in the first week of life between January 2006 and June 2009 to calculate the sensitivity and the specificity of the risk factors gathered by the German two-part general ultrasound screening. Ultrasound examination and classification was done according to the method of Graf.

Results

During the period of study a total of 5,100 hips were screened. Graf??s type I was seen in 4,290 hips (despite positive risk factors in 881 hips), corresponding to a prevalence of 84.1%. Graf??s type IIa was seen in 736 hips (despite positive risk factors in 221 hips), corresponding to a prevalence of 14.4%. Graf??s type IIc stable/instable was seen in 16 hips (despite a lack of risk factors in 13 hips), corresponding to a prevalence of 0.3%. Graf??s type D was found in 37 hips, 18 of which exhibited no risk factors, corresponding to a prevalence of 0.7%. Graf??s type III was diagnosed in 20 hips (despite a lack of risk factors in 8 hips, corresponding to a prevalence of 0.4%). One hip without any risk factors was screened as Graf??s type IV corresponding to a prevalence of 0.02%. Thus, the specificity of the risk factors gathered by the two-part screening for developmental dysplasia of the hip in Germany is 78.1% and the sensitivity 48.6%.

Conclusion

In 78.1% it is possible to detect a healthy hip as such in the third check-up for children between the fourth and sixth week of life with the German two-part ultrasound screening programme. However, only 48.6% of dysplastic or dislocated hips can be detected in the first week of life with this screening programme. Thus, less than 50% of dysplastic or dislocated hips will be treated as early as possible. Thus, every newborn should have an ultrasound screening of the hip during the first week of life independently of symptoms and history.     

新生儿发育性髋关节异常筛查结果分析

目的 探讨新生儿发育性髋关节异常(DDH)的发病情况.方法 选取2008年6月-2009年7月在本院住院和门诊就诊的762例足月新生儿(男382例,女380例).患儿均采用Graf法和Morin法相结合的超声检查手段进行髋关节测量.参照Graf分类方法将髋关节发育不良、髋关节半脱位和髋关节全脱位者定为DDH.对髋关节发育不良患儿采取随访观察,而对髋关节半脱位和髋关节全脱位的DDH患儿行早期Pavlik吊带治疗,同时采用超声跟踪随访6个月,以进一步决定治疗方案.结果 1.143例DDH新生儿中髋关节脱位的发病率为0.52%,髋关节发育不良的发病率为18.25%;2.健康新生儿619例髋关节超声测量指标α角、β角、股骨头覆盖率的正常值分别为(60.19±6.92)度、(45.25±7.29)度、(62.85±6.38)%,DDH患儿分别为(44.52±7.53)度、(58.45±10.36)度、(37.65±7.74)%,二组超声测量指标比较差异均有统计学意义(Pa<0.05);3.性别、胎位、分娩产式、左侧等均为髋关节脱位的高危因素.结论 1.超声检查是新生儿DDH筛查的首选方法.2.明确新生儿髋关节发育的指标、DDH的发病率及相关高危因素,有利于减少DDH发生,同时早期发现DDH、尽早治疗,可改善患儿预后.     

三维超声在筛查新生儿发育性髋关节异常中的探索性应用

目的 探索三维高频超声髋关节检查技术在诊断新生儿发育性髋关节异常(DDH)中的应用价值.方法 2010年6月至2010年12月,采用PHILIPS IU22超声诊断仪,二维加三维高频线阵探头,对768例新生儿行髋关节超声筛查.新生儿7d内行超声波髋关节筛查,采用Graf法及股骨头覆盖率比值测量髋关节,并结合三维成像图评判髋关节发育情况.结果 本组受检新生儿768例(1 536髋),其中女婴398例,男婴370例,新生儿平均受检时间为出生后5.8d.正常的髋关节共1 412髋,占91.92％;髋关节不稳定共99髋,占6.45％;髋关节发育不良19髋、半脱位4髋、脱位2髋,共占1.63％.结论 Graf的髋关节额状面成像技术,可以对新生儿髋关节进行清晰的超声成像,并进行了定性、定量分析,诊断DDH,但标准图像的获得是测量和诊断的关键,它会受操作者的技术影响.三维超声成像技术,可观察髋关节空间结构,旋转X、Y、Z轴,更可从不同角度观察髋关节的发育情况,提供髋关节解剖形态和关节功能的信息,并能早期显示髋关节解剖结构,这点是传统X线片不能比拟的优势,图像更加直观,加上高频超声波检查的无放射性损害,重复性强,因此二维和三维超声二者相结合诊断发育性髋关节异常,更符合临床上治疗髋臼发育不良的时间越早越好的需求.     

The ultrasonographic image of the infant hip affected by developmental dysplasia with a positive Ortolani's sign

Instability of the hip may be assessed by the Ortolani and Barlow tests, which are the keystone of clinical screening for developmental dysplasia of the hip (DDH). However, Ortolani's sign implies that there is strong evidence of a severe form of DDH with a completely dislocated, but still reducible, femoral head. Barlow's test addresses several different forms of "instability" of the hip that are quite difficult to describe and in 80% of cases disappear during growth. For this reason, Ortolani's sign in a baby should be considered an indication for emergency treatment to reduce and stabilise the hip while it is still reducible. The increasingly widespread use of US of the hip in newborns and infants has enabled clinicians to observe the hip from the first day of life and to establish both the static and dynamic relationships of the femoral head and acetabulum. The purpose of this paper is to describe the US pattern and relative classification of the hip affected by Ortolani's sign and examined by Graf's method, and to confirm through US that Ortolani's sign should be considered a totally reliable specific test for the identification of dislocation of the infant hip.     

The congenital dislocation of the hip joint in ultrasound examination--frequency, diagnosis and treatment

BACKGROUND: A real congenital dislocation of the hip joint is very rare. Because of the severeness of the disease an immediate diagnosis and begin of treatment is required. PATIENTS: Between 1984 and 1995 clinical and sonographic screening examinations at 4177 newborns were performed at our hospital. METHODS: We analyzed our patients retrospectively and found out all cases of congenital dislocation of the hip joint. All these cases were classified and the results of treatment were determined. The clinical success of our strategy of treatment was described. RESULTS: Among the 4177 observed newborns 39 cases of congenital dislocation of the hip joint in 27 children were found. We diagnosed the hip type IIIa, IIIb and IV according to Graf in 28.2 and 9 cases respectively. After 12 month a complete healing rate of 95 percent was exhibited with the functional management strategy. Five percent of the affected joints showed a residual dysplasia. The rate of residual dysplasias was 2.5%. CONCLUSIONS: The good prognosis after our early treatment strategy severe congenital dislocation of the hip joint underlines the use of earliest therapy together with a hip screening program.     

Value of limited hip abduction in developmental dysplasia of the hip

BACKGROUND: Developmental dysplasia of the hip (DDH) continues to be missed by routine physical examination in up to 50% of cases. Ultrasound (US) supplementation is the best method of screening for DDH, but the resources required should not be underestimated. Limited abduction of the hip (LHA) in an infant triggers suspicion, and often an urge to treat, in most orthopaedic surgeons and pediatricians alike. This study aimed to document the value of unilateral LHA in the diagnosis and decision making of DDH, and the correlation between LHA and US. METHODS: In total, 464 infants referred from the pediatrics clinic with LHA, aged between 30 and 120 days, were included in the study. RESULTS: Physical examination revealed LHA in 186 (41%) infants, 26 of which were unilateral and 160 were bilateral. US examination showed that 13 (8.1%) patients in the bilateral LHA group and 18 (69.2) patients in the unilateral LHA group, had DDH (total number 31, 7%). CONCLUSION: Unilateral limitation of hip abduction was found to be a sensitive sign for developmental hip dysplasia, but US could be defined once again as the best golden standard before initiating treatment.     

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.     

Ligurian experience on neonatal hearing screening: clinical and epidemiological aspects

AIM: Early identification and rehabilitation of newborns with congenital hearing impairment (HI) by Universal Neonatal Hearing Screening (UNHS). METHODS: The neonatal population was divided into two groups: babies with No Audiological Risk (NAR), and babies With Audiological Risk (WAR). NAR neonates underwent OAE testing, and in case of a doubtful (Refer) result, ABR testing was carried out. All WAR newborns underwent ABR testing within the third month of life. RESULTS: Between February 1, 2002 and December 31, 2004, UNHS was carried out on 32 502 newborns at the 13 regional birth centres, representing 98.7% of the whole regional neonatal population. The prevalence of HI in the population we tested was estimated at about 1 per thousand, while Bilateral Hearing Impairment (BHI) was estimated at 0.65 per thousand. A 3.7% prevalence of HI and a 2.8% prevalence of BHI was observed among the WAR population. Median age at the end of the diagnostic procedures was 6.7 months in the WAR population and 6.9 months in the NAR population. CONCLUSIONS: Our project is based on two levels of testing, which resulted in a 0.28% false-positive rate with 100% sensitivity and 99% specificity. Our screening is the first Italian experience that has been extended to a whole region and the results prove that regional neonatal hearing screening is feasible.     

Ultrasonography in developmental dysplasia of the hip: what have we learned?

Developmental dysplasia of the hip (DDH) is an important but poorly defined entity, the natural history of which is incompletely understood. The term encompasses a disease spectrum ranging from a stable hip with a mildly dysplastic acetabulum to complete hip dislocation. Much controversy surrounds the diagnosis, imaging and management of this condition. We present a review of the history of US imaging of DDH from the radiologist’s perspective, summarising the most widely recognised US methods described to date. We discuss controversies in the approach to US examination, with particular emphasis on current opinions. The existing scientific evidence for and variations in the practice of US screening for DDH, including recommendations from the United States Preventive Services Task Force and the ESPR DDH Taskforce Group respectively, are discussed.     

Ultrasound screening of high-risk infants. A method to increase early detection of congenital dysplasia of the hip.

Congenital dysplasia of the hip (CDH) continues to be missed by routine physical screening examinations in the early months when treatment is most effective. Real-time ultrasonography (US) is valuable in the detection of CDH in the young infant. We performed a prospective study to evaluate one US screening strategy that targets a select "high-risk newborn" population at risk for CDH aiming to increase the early diagnosis of this condition. From 1772 consecutive births at one hospital, we identified 97 (5.5%) newborns with risk factors for CDH: breech delivery, 73 babies; family history, 26 babies; postural abnormalities, five babies; and oligohydramnios, four babies. Eleven newborns had two risk factors. We studied 69 of these newborns with US. There were four cases of CDH in this group. Three of these babies had completely normal pediatric physical examination results at the time of the US study (at 14, 75, and 100 days, respectively) despite dysplasia diagnosed by US. All were successfully treated with a harness as outpatients. We conclude that a screening program entailing identification and subsequent US of the hip of newborns with specific physical and historical risk factors for CDH increases early diagnosis. Further analysis suggests this approach is cost-effective.     

Graf Ⅱ型发育性髋关节脱位409例不同干预后转归的回顾性多中心研究

目的 比较3种干预方式(蛙式抱、Pavlik挽具,宽尿不湿及屈髋外展被动操)对发育性髋关节脱位(DDH) GrafⅡ型患儿的疗效,探讨超声随访与X线随访的关系.方法多中心、观察性临床研究,纳入中国7个城市7家儿童医院2011年1月至2015年12月409例Graf Ⅱ型DDH患儿的资料,对其临床表现、干预方式、诊治经过、影像结果等进行回顾性分析.采用单因素方差分析两两比较,评估3种不同干预方式对Graf Ⅱa型DDH患儿的转归.采用单因素方差分析,评估Pavlik挽具及非Pavlik挽具(蛙式抱、宽尿不湿以及屈髋外展被动操)对Graf Ⅱb型DDH患儿的转归.采用配对四格表Fisher确切概率法,比较超声检查发现异常的阳性率和X线检查的差异.结果 409例中,男124例,女285例;Graf Ⅱa型292例,Ⅱb型102例,Ⅱc型14例,Ⅱd型1例.Graf Ⅱa型DDH患儿分别采用3种干预方式干预后,正常转归时间分别为:Pavlik挽具,平均38 d;宽尿不湿及屈髋外展被动操,平均46 d;蛙式抱,平均56 d,差异有统计学意义(F=9.422,P=0.0001).Graf Ⅱb型DDH患儿采用Pavlik挽具与非Pavlik挽具干预正常转归时间分别为32 d和45 d,差异有统计学意义(F=5.566,P=0.001).超声检查和X线随访检查发现异常结果的阳性率分别为9.05％(18/199)和0.50％(1/199),差异无统计学意义(x2=10.106,P=0.09).结论 Graf Ⅱ型DDH均能用Pavlik挽具治愈.对Graf Ⅱa型、Ⅱb型DDH患儿,Pavlik挽具干预与宽尿不湿及屈髋外展被动操干预、单纯蛙式抱干预比较,治愈所需时间最短.所有409例临床随访均未发现髋关节异常;超声是随访评价Graf Ⅱ型DDH患儿有效的工具.     

Screening for developmental dysplasia of the hip: Results of a 7-year follow-up study

BACKGROUND: Screening for developmental dysplasia of the hip (DDH) is widely recommended for all infants to prevent disability from late diagnosis of dislocation of the hip. The present study evaluates the results of screening for developmental dislocation of hip in a clinic in Turkey over the course of 7 years. METHODS: Hospital records of 5798 infants who were examined regularly until walking age at Gazi University well child clinics between January 1995 and December 2001 were reviewed. Infants with known risk factors for DDH such as breech presentation, family history of DDH or swaddling, and of infants with physical examination findings suggestive of DDH, were referred to orthopedic surgeons for diagnosis. Based on this final diagnosis, sensitivity, specificity, positive and negative predictive values of risk factors and physical examination findings were calculated. RESULTS: Of the 5798 infants, risk factors were detected in the medical history of 111 infants, and in 14 infants a musculoskeletal deformity was detected. In 606 infants the physical examination findings were suggestive of DDH. Ten patients were subsequently diagnosed with DDH. The sensitivity, specificity, positive predictive value and negative predictive values of having a risk factor for DDH in history were 10.0%, 98.1%, 0.9%, 99.8%, and having abnormal hip examination findings were 100.0%, 88.9%, 1.6% and 100.0%, respectively. CONCLUSIONS: A careful history and physical examination is the cornerstone of DDH screening. Serial hip examinations performed during health examination visits provide an opportunity to identify DDH cases. The sensitivity of risk factors in history and physical examination findings together is high enough to be accepted as a screening tool.     

Selective ultrasound screening for developmental hip dysplasia: effect on management and late detected cases. A prospective survey during 1991–2006

Background

Early treatment is considered essential for developmental dysplasia of the hip (DDH), but the choice of screening strategy is debated.

Objective

We evaluated the effect of a selective ultrasound (US) screening programme.

Materials and methods

All infants born in a defined region during 1991–2006 with increased risk of developmental dysplasia of the hip, i.e. clinical hip instability, breech presentation, congenital foot deformities or a family history of DDH, underwent US screening at age 1–3 days. Severe sonographic dysplasia and dislocatable/dislocated hips were treated with abduction splints. Mild dysplasia and pathological instability, i.e. not dislocatable/dislocated hips were followed clinically and sonographically until spontaneous resolution, or until treatment became necessary. The minimum observation period was 5.5 years.

Results

Of 81,564 newborns, 11,539 (14.1%) were identified as at-risk, of whom 11,190 (58% girls) were included for further analyses. Of the 81,564 infants, 2,433 (3.0%) received early treatment; 1,882 (2.3%) from birth and 551 (0.7%) after 6 weeks or more of clinical and sonographic surveillance. An additional 2,700 (3.3%) normalised spontaneously after watchful waiting from birth. Twenty-six infants (0.32 per 1,000, 92% girls, two from the risk group) presented with late subluxated/dislocated hips (after 1 month of age). An additional 126 (1.5 per 1,000, 83% girls, one from the risk group) were treated after isolated late residual dysplasia. Thirty-one children (0.38 per 1,000) had surgical treatment before age 5 years. Avascular necrosis was diagnosed in seven of all children treated (0.27%), four after early and three after late treatment.

Conclusion

The first 16 years of a standardised selective US screening programme for developmental dysplasia of the hip resulted in acceptable rates of early treatment and US follow-ups and low rates of late subluxated/dislocated hips compared to similar studies.     

Description of the ‘pronation manoeuvre’ for the diagnosis of developmental hip dysplasia

IntroductionWithout a prompt diagnosis, developmental dysplasia of the hip (DDH) in infants can lead to severe sequelae. Current screening strategies emphasize the use of Ortolani and Barlow physical examination manoeuvres, yet they exhibit low sensitivity. The purpose of this study is to evaluate the performance of a new physical examination tool (the pronation manoeuvre) as a screening tool for DDH.MethodsTo evaluate the new manoeuvre, a cross-sectional and analytic study was performed with a nonprobabilistic sampling method. Patients with either a positive Ortolani or Barlow manoeuver were evaluated with the new manoeuvre and hip ultrasound. Controls were infants with negative Ortolani, Barlow and pronation manoeuvres and also had ultrasound performed.ResultsDDH was confirmed in 83 of 130 cases (64%) and 2 of 130 controls (2%). The new pronation manoeuvre had a sensitivity of 76% and a specificity of 94% as compared to the Ortolani and Barlow manoeuvres (sensitivity 31 to 32%, specificity 93 to 100%) (P<0.05).ConclusionThis new physical examination manoeuvre could serve as another clinical tool for the initial screening of DDH in newborns. Its promising results against traditional screening procedures might potentially impact diagnosis and prognosis for patients with DDH.     

Echotomography diagnosis of congenital hip dysplasia. Experience with 1120 cases

The congenital hip dysplasia is based on an abnormal acetabular rim, with pathologic capsula and ligaments. These pathologic structures can lead to the subtotal or total dislocation of the hips. In newborns the joint cartilaginous structures, can be visualized by sonography and it is possible to diagnose the different grade of dysplasia. Our series, in part previously selected, consist in 1120 joints. The results in newborns up to 3 months of age are: normal joints 79.5%, immature 10.7%, pathologic 9.8%. After 3 months of age: normal joints 93%, dysplastic 5.2%, subdislocated 0.6%, dislocated 1.2%. In all the cases we used the morphologic Graf technique and in newborns also the dynamic examination according to Novick to precise the minimal degree of the instability of the hips. Sonography permits an early diagnosis of hip dysplasia without false positive or negative results.     

Riesgo de displasia del desarrollo de la cadera en pacientes sometidos a versión cefálica externa

Introduction

Developmental dysplasia of the hip (DDH) refers to the spectrum of abnormalities of maturation and development of the hip. Breech presentation is associated with DDH. This risk factor can be modified by external cephalic version (ECV). The aim of this study is to evaluate the incidence of DDH in patients who successfully underwent ECV, as well as to evaluate need for these children (breech for a period during gestation) to be included in the DDH screening protocol.

Effectiveness of ultrasound screening for developmental dysplasia of the hip

OBJECTIVE: To determine the effectiveness of ultrasound screening for developmental dysplasia of the hip (DDH) after the neonatal period. DESIGN: Prospective cohort study. SETTING: Child health care centres. PARTICIPANTS: Infants attending the child health care centres. INTERVENTIONS: The intervention group (n = 5170) was screened by ultrasound at 1, 2, and 3 months of age. The control group (n = 2066) was screened by routine physical examination as part of the programme for child health surveillance at the child health care centres (CHC screening). For evaluation of the screening, the children in both the intervention and control group received an ultrasound examination after 6 months of age to detect any abnormality that might have been missed by the screening. RESULTS: The sensitivity of the ultrasound screening was 88.5%, and the referral rate 7.6%. As a result of the ultrasound screening, 4.6% of the children were treated. The sensitivity of the CHC screening was 76.4%, with a referral rate of 19.2%. The treatment rate was 2.7%. Of the treated children in the ultrasound screening group, 67% were referred before the age of 13 weeks, whereas in the CHC screening group only 29% were referred before this age. CONCLUSIONS: This study shows that ultrasound screening detects more children with DDH than CHC screening and that more of them are detected at an earlier age. To accomplish this, even fewer children have to be referred. However, even general ultrasound screening seems not to eradicate late cases of DDH. The higher treatment rate in the population screened by ultrasound may be a result of overtreatment.     

新生儿髋关节筛查资料分析

目的 探讨超声及临床髋关节检查在新生儿发育性髋关节发育不良（DDH）早期筛查中的意义.方法 采用前瞻性的方法,分两阶段对我院2011年8月1日至2013年3月29日出生的新生儿分别进行髋关节临床检查和超声检查,并对筛查结果进行分析.第一阶段为2011年8月1日至2013年1月29日,筛查出生3 ～ 10天的新生儿,了解我院新生儿DDH的患病率、DDH发生的高危因素,以及髋关节超声筛查和临床物理检查两者之间的吻合度等.第二阶段为2013年1月30日至2013年3月29日,对初诊与复诊的一致性及灵敏度和特异度进行调查.结果 第一阶段共筛查5193例新生儿,临床髋关节检查阳性616例（11.86％）,超声检查阳性556例（10.71％）.男、女超声阳性率分别为6.41％和15.78％.臀位及羊水量少的新生儿超声检查阳性率分别为10.55％和13.00％.男、女左、右髋超声分度比较和男、女左髋、右髋、双髋超声检查比较显示,女婴、臀位、羊水量少、右髋发生DDH的风险高,差异有统计学意义（P＜0.05）.第二阶段共筛选出符合超声初查和复查双条件的新生儿108例,初诊与复诊结果差异无统计学意义（P＞0.05）.ROC曲线下面积为0.675（95％ CI：0.183～1.000）.阳性预测值5.88％,阴性预测值98.90％.灵敏度及特异度的95％可信区间分别为50.00％ （95％ CI：1.26％ ～ 98.70％）,84.90％（95％ CI：76.60％ ～91.10％）.结论 超声进行新生儿髋关节DDH检查排除性诊断的意义大.运用髋关节临床及超声检查筛查新生儿DDH简便、安全,可早期发现可疑及异常病例,有利于门诊随访和早期干预.     

Differences in risk factors between early and late diagnosed developmental dysplasia of the hip

BACKGROUND: Developmental dysplasia of the hip (DDH) is common, affecting 7.3 per 1000 births in South Australia. Clinical screening programmes exist to identify the condition early to gain the maximum benefit from early treatment. Although these screening programmes are effective, there are still cases that are missed. Previous research has highlighted key risk factors in the development of DDH. OBJECTIVE: To compare the risk factors of cases of DDH identified late with those that were diagnosed early. METHODS: A total of 1281 children with DDH born in 1988-1996 were identified from the South Australian Birth Defects Register. Hospital records of those who had surgery for DDH within 5 years of life were examined for diagnosis details. Twenty seven (2.1%) had been diagnosed at or after 3 months of age and were considered the late DDH cases (a prevalence of 0.15 per 1000 live births). Various factors were compared with early diagnosed DDH cases. RESULTS: Female sex, vertex presentation, normal delivery, rural birth, and discharge from hospital less than 4 days after birth all significantly increased the risk of late diagnosis of DDH. CONCLUSIONS: The results show differences in the risk factors for early and late diagnosed DDH. Some known risk factors for DDH are in fact protective for late diagnosis. These results highlight the need for broad newborn population screening and continued vigilance and training in screening programmes.