Prognostication in Developmental Dysplasia of the Hip Using the Ossific Nucleus Center Edge Angle.
BACKGROUND
The aim of this paper was to determine the prognostic potential of the ossific nucleus center edge angle (ONCEA) in patients below 5 years of age treated for developmental dysplasia of the hip (DDH) to predict final outcome and the need for a secondary procedure.


METHODS
The interobserver and intraobserver reliability was calculated using the intraclass correlation coefficient for measurement of the ONCEA. The ONCEA was divided a priori into 3 groups: group A≥10 degrees, group B -9 to 9 degrees, and group C ≤-10 degrees. Final outcome was measured using the McKay score and Severin classification. The presence of osteonecrosis was recorded at final follow-up.


RESULTS
One hundred one patients with 133 dislocated hips underwent closed or open reduction for DDH. Mean age at presentation was 19 months with a mean age at final follow-up of 12.4 years. A significant difference was shown in a comparison of the 3 ONCEA groups using the McKay score, Severin classification, and need for a secondary procedure. Eighty seven of the 101 patients underwent ONCEA reliability measurements. The ONCEA was shown to have a mean intrarater reliability of 0.89, and a mean interrater reliability of 0.77.


CONCLUSIONS
The ONCEA is a reliable measurement in predicting medium-term outcome of the hip post reduction in children under the age of 5 years with DDH and might be useful as a predictor for a secondary procedure before the age of 5 years.


METHODS
Level III-prognostic case control study.


CONCLUSIONS
This case control study shows the importance of measuring the ONCEA within 6 months of removing the final cast after reduction of a dislocated hip and its implications for further management and outcome.
Division of Orthopaedic Surgery, Faculty of Health Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa.
Gregory B
GB
Firth
Division of Orthopaedic Surgery, Faculty of Health Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa.
Anthony J F
AJF
Robertson
Division of Orthopaedic Surgery, Faculty of Health Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa.
Yammesh
Y
Ramguthy
Department of Orthopaedic Surgery, University of London, London, United Kingdom.
Manoj
M
Ramachandran
Division of Orthopaedic Surgery, Faculty of Health Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa.
Anton
A
Schepers
D000886:Anthropometry / Q000379:methods*; D016022:Case-Control Studies; D002675:Child, Preschool; D005260:Female; D006618:Hip Dislocation, Congenital / Q000175:diagnosis*; D006801:Humans; D007223:Infant; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies