1. The intramedullary rod has been used to control the alignment of the osteotomized fragments in twenty-three operations performed for the lengthening of the femur, and it has been found to be eminently satisfactory, eliminating many of the difficulties which were formerly encountered in maintaining the position of the osteotomized fragments.

2. In addition to the conventional osteotomies by step-cut or oblique section, a transverse osteotomy has been performed. The combination of the intramedullary rod and the transverse osteotomy has simplified the femoral-lengthening operation and has afforded the best means yet known for the control of the fragments.

3. A primary union of the bone fragments occurred as readily after a transverse osteotomy as it did after the other types of osteotomy which provide for a contact of the bone fragments throughout the lengthening procedure. This indicates that during its growth the bone callus may be stretched out in length.

4. A delayed union of the bone occurred with an undesirable frequency. From their experience with this series the authors could not determine the cause of the delayed union nor can they present any definite information concerning the optimum time for starting the lengthening procedure after the performance of the osteotomy.

5. It would appear that the more the bone is lengthened, the longer is the time required for the union of the fragments and the more likelihood there is of non-union.

6. While the etiology of the shortening has no bearing upon whether union of the fragments will occur or not, it does have some influence on the success of the procedure for lengthening. Shortening of an acquired nature responded more readily to the lengthening procedure than did that resulting from a congenital failure of the growth of the limb. It may he concluded, in the latter instance, that the soft tissues are structurally adapted to the shortened bone and therefore less elastic than those in the limb which has become shortened because of an acquired disturbance of its growth.

7. In addition to the complications involving the healing of the osteotomy, many other complications have occurred. While the intramedullary rod and the transverse osteotomy have simplified the operation, this method has not influenced the occurrence of the complications resulting from the resistance of soft tissues and the stretching of the vessels and the nerves of the thigh. Much more attention must be directed toward these problems in order to avert neurovascular complications and deformities of the knee joint.