This cohort illustrates growth of the center of ossification of the femoral head during and after orthopedic reduction of congenital hip dislocation.

Thirty files of pediatric patients with congenital hip dysplasia were studied retrospectively. Mean age of the children was 24.5 months. All had unilateral dysplasia, allowing a comparison of femoral head growth by calculating the centers of ossification on the AP views.

Mean ratio between the radiological surface of the center of ossification of the femoral head on the dysplastic side and the normal side was about 1: 2. This ratio progressed rapidly during the first months after reduction and became 1: 1 at a mean 43 months after reduction. Beyond this time, growth of the femoral heads followed a similar pattern.

Growth of the center of ossification of the femoral head is related to biomechanical stress forces. Reduction is the only event in the natural history of the disease, but renewed growth of the femoral head cannot provoke in itself normal acetabular growth. Complementary pelvic osteotomy was required for 13 hips.

Accelerated growth of the femoral head ossification center continues to be a good indicator of femoral head vitality. Early and rapid growth observed after reduction, without osteochondritis, can lead to a normal femoral head at the end of growth.