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.
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.
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.
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.
Level of Evidence:
Level III—prognostic case control study.
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.