The analysis of the results to date of fifty-nine varus osteotomies with or without derotation to correct anteversion done for congenital dislocation and subluxation of the hip indicates that the following advantages are obtained:
1. The procedure permits complete concentric reduction of the femoral head;
2. The dynamic and static forces maintaining reduction of the hip are improved;
3. As a result of advantages 1 and 2, greater stability is obtained and maintained:
4. The tendency to subsequent subluxation is reduced (there have been no redislocations in this series):
5. The incidence of aseptic necrosis is decreased;
6. The surgically produced varus position—a neck-shaft angle 90 to 100 degrees—tends with growth to return to a normal neck-shaft angle;
7. The varus position is easily produced at the time the derotation osteotomy is done to correct anteversion:
8. Complications are minimum;
9. The necessity for further surgical procedures is reduced.