Deformity of the proximal end of the femur following open reduction for developmental dislocation of the hip

We studied deformity of the proximal end of the femur following open reduction using the wide exposure method for developmental dislocation of the hip. We reviewed radiographs of 22 children with unilateral dislocation of the hip who had undergone open reduction between one and three years of age. Ages at final examination ranged from 14 to 21 years. None of the patients in this study had undergone any additional surgery. Avascular necrosis of the femoral head was not observed in any patients. Radiographic measurements were observed when the children were 3, 6, 9, and 12 years old, and at the final examination. Coxa magna and valga were the factors associated with poor results. Coxa valga had occurred at 6 to 12 years of age, but rapidly improved thereafter. Throughout the course of treatment the epiphysis-femoral neck angle was within the normal range. The fusion of the epiphyseal growth plates on both sides occurred simultaneously. The coxa valga was due to valgus of the femoral neck, and not to valgus head tilt. These results suggest that, provided the mechanics of the joint have been properly corrected as in our operation, the biomechanics of the hip will improve until growth ceases, but that it may take more than ten years to attain normality.