Long-term results of closed reduction of complete congenital dislocation of the hip in children under one year of age.

Eight to 29 year follow-up investigation of the results of closed reduction in 40 completely dislocated hips in children, treated under one year of age, show that 92.5% of the hips had good functional results and 77.5% had good anatomical results. The slant and depth of the acetabular roof rapidly improved during the first year after reduction and slowly during the following 8 years. Femoral head necrosis occurred in 12 hips (30%). The necrosis was mild in 4 hips and severe in 8. The 8 hips with severe femoral head necrosis had poor anatomical results. Surprisingly, the development of the acetabulum was not influenced by femoral head necrosis. Femoral head necrosis was frequently observed when the head was in a high position in relation with the acetabulum prior to reduction. Closed reduction should not be attempted unless the head can be brought down below the level of the acetabulum.