1. Lengthening of the tibia and fibula is a procedure which is of great value in cases where the major part of the shortening of a lower extremity is confined to these two bones.

2. The fundamental principles of leg lengthening are the application of traction and countertraction directly to the bone and continued over a considerable period of time. To avoid complications and to promote early union, apposition of the fragments in good alignment is essential. This is best secured by applying traction on both sides of the leg by means of screw extension pieces which are attached to pins passed through the upper and lower ends of the shaft of the tibia. Displacement in an anteroposterior direction is prevented by stabilizers which hold the drill pins in the same horizontal plane.

3. In this operation, because of multiple incisions, penetrating drill pin wounds and the wide opening of the medullary cavity of the tibia, there is considerable danger of infection. This can be minimized by gentle handling of the tissues and by observing the most rigid, aseptic technique throughout the operation.

4. In the six cases treated by this method the lowest gain in length was one and one-quarter inches; the largest one and seven-eighths inches. The results in the completed cases have been highly satisfactory and with the experience which we have acquired we believe that in the average case a gain of two inches should be secured without producing an injury to the blood vessels or nerves.

5. With the operation in its present stage of development, we believe that it should be performed only by those who are adequately equipped to do bone surgery and who by their training have a thorough knowledge of mechanical appliances.

6. It should not become a routine procedure but should be reserved for those who are actually in need of it—those who cannot be relieved by more conservative measures.