Pubo-femoral distance: an easy sonographic screening test to avoid late diagnosis of developmental dysplasia of the hip.
OBJECTIVE
To propose an easy and reproducible sonographic screening test able to avoid late presentation of developmental dysplasia of the hip (DDH).


METHODS
The pubo-femoral distance (PFD) cut-off point was determined on 980 infants who underwent ultrasonography of the hips in comparison with the final diagnosis, based on clinical, ultrasound data and follow-up. PFD reproducibility was tested on 52 hips by both an experienced and an inexperienced radiologist. After teaching this screening method to general radiologists, its impact was evaluated by analysing the rate of late diagnosis in an entire administrative area.


RESULTS
An abnormal PFD threshold above 6 mm gave a sensitivity of 97.4 % for the diagnosis of DDH (271 hips) and a specificity of 84 %. Sensitivity increased to 100 % when taking into consideration children of 1 month or older. The PFD measurement stayed reproducible even in inexperienced hands (k = 0.795). For 3 years, following the extension of screening to all female infants, there was no late diagnosis of DDH in girls in amongst a catchment area of 1 million inhabitants.


CONCLUSIONS
PFD measurement with a threshold for abnormality of 6 mm at the age of 1 month, without asymmetry above 1.5 mm, could eradicate DDH late diagnosis.
Department of Radiology, Hôpital Sud, University Hospital, Rennes, France. catherine.treguier@chu-rennes.fr
C
C
Tréguier
M
M
Chapuis
B
B
Branger
B
B
Bruneau
A
A
Grellier
K
K
Chouklati
M
M
Proisy
P
P
Darnault
P
P
Violas
P
P
Pladys
Y
Y
Gandon
D000465:Algorithms; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging*; D002675:Child, Preschool; D057210:Delayed Diagnosis / Q000517:prevention & control*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000379:methods; D011630:Pubic Bone / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography