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Titel på arbejdetPubo-femoral distance measurements in screening for developmental dysplasia of the hip
NavnHans-Christen Husum
Afdeling / StedOrtopædkirurgisk Afdeling / Aalborg Universitetshospital
UniversitetAalborg Universitet
  • Orthopaedic Pediatrics
Abstract / Summary

Screening for developmental dysplasia of the hip (DDH) has been performed in the developed world for several decades. Initially the screening consisted of clinical examinations of hip stability, but with the introduction of hip ultrasound (US) in the 1980s, mass screening of DDH based on hip morphology was made possible.
The advent of US screening also introduced the question of which children should receive a hip US, launching a debate that is still ongoing. Should they be referred for US based on a DDH risk assessment (selective screening) or should all children receive a hip US (universal screening)?
While universal screening has been pursued in some countries, today most screening programmes for DDH apply the selective screening approach citing, among other issues, the increased financial cost of universal screening but also the need for specialised examiners to perform the US screening.
Over the years, evidence indicating an inadequacy of selective screening to reduce late diagnoses or ultimately surgical treatment for DDH, has been reported. Health policy makers are therefore left with the choice of either continuing a possible ineffective screening programme or to pursue universal screening, in a time where health care resources are becoming increasingly scarce.
The present thesis presents a possible middle-ground, by investigating the pubo-femoral distance (PFD) as a more accessible US metric, allowing inexperienced US examiners to perform US screening, thus driving down the cost and personnel requirements of a universal US screening programme.
The PFD method is investigated in three separate studies.
First, the accessibility of the PFD method was assessed in the hands of midwives as novice US users. We designed a training programme with the purpose of documenting the learning curve of novice US users learning the PFD method as well as comparing the measurements to those produced by experienced musculoskeletal radiologists.
Second, the midwives trained in the PFD method were employed in a hybrid selective screening programme for DDH. This screening programme retained the traditional clinical examination and risk factor identification of selective screening while adding universal PFD US as a stand-alone referral criterion. The performance of the traditional selective screening and universal PFD screening was then compared in terms of effectiveness in detecting DDH.
Third, while the PFD method has been documented to correlate to DDH, and consequently correlated to the gold standard US methods used in DDH diagnostics, the degree of correlation had never been investigated. Therefore, using the study population of the hybrid screening programme, we assessed the correlation of the PFD measurement to the gold standard US metrics.
In short, the present thesis aims to provide the argument for the PFD method as a screening tool in locations where universal US screening using the gold standard methods are not feasible.
We found a rapid learning curve, higher efficiency of PFD screening compared to traditional selective screening and a strong correlation to gold standard US metrics. These findings suggest that PFD screening may be a viable alternative to traditional selective screening and an acceptable compromise to universal US screening based on the current gold standard methods.

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