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    How Common Is Late Detection of DDH in Children?

    A study from the UK indicates that the incidence of late-detected developmental dysplasia of the hip hasn’t changed in 50 years. Is it time to implement universal ultrasound in newborns to improve early detection and intervention?

    Authors

    Neha Jejurikar, MD, and Pablo Castañeda, MD

    Article

    Broadhurst C, Rhodes AML, Harper P, Perry DC, Clarke NMP, Aarvold A. What is the incidence of late detection of developmental dysplasia of the hip in England?: a 26-year national study of children diagnosed after the age of one. Bone Joint J. 2019 Mar;101-B(3):281-287.

    Summary

    The most frequent cause of degenerative osteoarthritis requiring a total hip arthroplasty in young adults is developmental dysplasia of the hip (DDH). This is striking: The profound impact DDH can have on a young adult’s life could be easily mitigated with early diagnosis and simple non-operative treatment. Later diagnosis leads to:

    • Worse outcomes
    • An increase in the number of operations
    • Longer hospital stays
    • Higher costs to the healthcare system
    • Long-term complications

    Despite efforts by the UK’s National Health Service to avoid late diagnosis by implementing a selective screening program, late detection of DDH is a persistent problem in that country. The approach – universal screening by physical examination with ultrasound screening for “high-risk” babies – is also advocated in the US by:

    • United States Preventive Services Task Force (USPSTF)
    • American Academy of Pediatrics
    • American Academy of Orthopedic Surgeons
    • Pediatric Orthopedic Society of North America

    In contrast, other countries such as Austria and Germany have truly universal screening with ultrasound, resulting in negligible rates of late-diagnosed DDH. [1,2]

    The lack of consensus on an approach to DDH screening has fueled debate over the utility of newborn screening and the possibility that universal screening could result in increased costs and overtreatment. 

    To establish the incidence of DDH diagnosed in children over age 1 in the UK, Broadhurst et al utilized 2 UK databases – the Clinical Practice Research Datalink (CPRD) and the Hospital Episode Statistics (HES) – to identify 835 children who:

    • Were between the ages of 1 and 8 (born between January 1, 1990, and January 1, 2016)
    • Had a new diagnosis code for DDH
    • Had continuous follow-up and good quality data, as defined by CPRD

    They then excluded 81 patients with coexisting neuromuscular disease, teratologic or syndromic DDH, or traumatic hip dislocation. That left 754 patients with a diagnosis of DDH after age 1 for their observational study. Data on these patients were then stratified by age, gender, year, and region of diagnosis.

    The incidence of late-diagnosed DDH in the UK was found to be 1.28 per 1000 live births. The peak incidence identified among age groups was between the ages of 1 and 2 years, with an incidence of 0.88 per 1000 live births. This represented 536, or 71.1%, of the children studied.

    Six hundred eight patients (80.6%) were female and 146 (19.4%) were male, creating a ratio of 4.2:1 female to male. The distribution of late-diagnosed DDH was evenly spread geographically throughout the UK, and racial/ethnic distributions matched the country’s population distributions.

    Clinical Relevance

    Access to a national dataset makes the study by Broadhurst et al the largest national study on late-detected DDH to date. The findings present a unique opportunity to study the effects of a selective screening program on a national level:

    • In this study, Broadhurst et al found the incidence of late-detected DDH in in the UK to be 1.28 per 1000 live births among children born between January 1, 1990, and January 1, 2016.
    • A study from Southampton, UK, found the incidence of late-diagnosed DDH to be 0.47 per 1000 live births in children born between 1965 and 1978. [3]
    • A study from Bristol, UK, found the incidence of late-diagnosed DDH to be 0.39 per 1000 live births in children born between 1970 and 1979. [4]

    As these statistics show, the incidence of DDH has not been reduced with implementation of a national selective screening program. This is crucial in understanding that clinical evaluation is clearly insufficient to detect all cases of DDH.

    In addition, Broadhurst et al found the peak incidence of late-diagnosed DDH to be in the age range of 1 to 2 years, which is consistent with clinical correlation. Children begin walking at that age and abnormal gait patterns are subsequently identified.

    A major limitation of the study by Broadhurst et al is the reliance on the accuracy of the codes used within the national databases. Varying codes reflecting unstable hips and dislocated hips were grouped under the similar category of dysplastic hips for this study.

    The authors could not explore family history and breech presentation, key factors in the selective screening parameters, due to inconsistent coding. In addition, age cohorts in CPRD are limited to annual increments; therefore, the authors could not study DDH incidence in children presenting between ages 6 and 11 months. As a result, the reported data could be an underestimation of the true incidence of a late DDH diagnosis.

    The study also highlights the fact that “late-detected DDH” is not a universally agreed-upon term. A recent study from Australia considered “late-detected” DDH to be detection after 8 weeks of age. [5] This is in contrast to many countries, especially in the developing world, where DDH is often detected after walking age.

    Broadhurst et al demonstrate the minimal impact selective screening has had on reducing DDH incidence, as well as the burden of DDH in the UK, and highlights that steps must be taken to better understand the cost-benefit analysis of universal screening. Although the US has a different patient population, lessons can be learned from the failure of UK’s selective screening program to reduce DDH burden.

    In 2006, the USPSTF issued the following statement: “Evidence is insufficient to recommend routine screening for developmental dysplasia of the hip in infants as a means to prevent adverse outcomes.” This is unfortunate, as the inconclusive statement leaves primary care physicians and pediatricians without guidance on appropriate newborn screening practices. It should be noted that the USPSTF currently states that it is reviewing this policy.

    With decreased cost and increased availability of ultrasound, as well as higher-quality ultrasound training in the current workforce, the need for universal screening with ultrasound and so-called “ultrasound-enhanced” physical examination seems more compelling than ever.

    In addition, artificial intelligence, machine learning capabilities, and augmented reality have the potential to dramatically alter the diagnostic potential of ultrasound imaging and reduce operator-dependent flaws. [6] Further study must match the pace of advances in ultrasound imaging to reduce unnecessary disability in children related to late-diagnosed DDH.

    Author Information

    Neha Jejurikar, MD, is a resident in orthopaedic surgery at NYU Langone Health, New York, New York. Pablo Castañeda, MD, is The Elly and Steven Hammerman Professor of Orthopaedic Surgery at NYU School of Medicine and Division Chief, Pediatric Orthopaedic Surgery, at NYU Langone Health/Hassenfeld Children’s Hospital, New York, New York.

    Disclosures

    The authors have no disclosures relevant to this article.

    References

    1. Thallinger C, Pospischill R, Ganger R, et al. Long-term results of a nationwide general ultrasound screening system for developmental disorders of the hip: the Austrian hip screening program. J Child Orthop 2014;8:3–10.
    2. von Kries R, Ihme N, Oberle D, et al. Effect of ultrasound screening on the rate of first operative procedures for developmental hip dysplasia in Germany. Lancet 2003;362:1883–1887.
    3. Catford JC, Bennet GC, Wilkinson JA. Congenital hip dislocation: an increasing and still uncontrolled disability? Br Med J (Clin Res Ed) 1982;285:1527–1530.
    4. Dunn PM, Evans RE, Thearle MJ, Griffiths HE, Witherow PJ. Congenital dislocation of the hip: early and late diagnosis and management compared. Arch Dis Child 1985;60:407–414.
    5. Studer K, Williams N, Antoniou G, et al. Increase in late diagnosed developmental dysplasia of the hip in South Australia: risk factors, proposed solutions. Med J Aust. 2016;204(6):240.
    6. Jha S, Topol EJ. Adapting to Artificial Intelligence: Radiologists and Pathologists as Information Specialists. JAMA. 2016;316(22):2353-2354.