1. This operation, so far as I have been able to learn, is here reported for the first time.
2. The basic principle of the operation consists in the adjustment of the disproportion between the lengths of the bones and the soft parts by means of an osteotomy below the femoral trochanters.
3. It provides a means for the reduction of a type of case which previously it was impossible to do either by manipulation or operative means.
4. The cases included in this type are the older or more developed children who present acetabula and femoral heads of fairly normal shape and relative size.
5. The success of the operation appears to depend upon the careful clearing of the acetabulum, gentle and accurate transection of the midportion of the joint capsule, strong suturing of the overlapped capsule, and proper approximation and alignment of the bone fragments.
6. The cases as yet are too few and too recent to prophesy the future of this operation, but the only apparent obstacle to a considerable range of usefulness lies in the possibility of too great a degree of disturbed or altered growth and development of the femoral head, neck, and trochanters.