The delayed autogenous bone gtaft is capable of stimulating osteogenesis. The extra supply of alkaline phosphatase and the attached newly formed bone may contribute to osteogenesis. Bony union occurred in each instance. The principal problem is one of meticulously nurturing the young bone until it. can withstand the physiological forces anti, later, the functional demand. Reinforcement of the newly formed tibia at its weak point, as evidenced by narrowing or incipient bowing, is imperative. Osteosynthesis of the fibula is believed to be of great value, not only in offering additional strength to the young tibia, but also in maintaining axial alignment. The importance of the continuation of primary immobilization until the medullary cavity has been formed, cannot be overemphasized. It offers the only criterion for the discontinuation of primary immobilization, by means of four pins and plaster fixation. A bimonthly toentgenographic check-up is essential during the first two years.

The follow-up period in all of the cases is probably too short to justify final conelusions. The fact that union occurred in every case in which the delayed graft was used, including those cases in which re-operation was done, is distinctly encouraging, and points to the effectiveness of this type of graft. In L. C., bending started at a narrowed point in the tibial graft, but prompt reinforcement with cortical grafts (not delayed grafts), at the site of the apparent weakness, prevented spontaneous fracture and brought about proper restoration. In the two cases in which spontaneous fracture occurred, it could probably have been avoided, had early bending been detected and the area been reinforced. In addition, if the policy of reinforcement were employed early—that is, when the graft became narrowed or at the time of the incipient bending—the danger of spontaneous fracture would be reduced.

The treatment of congenital pseudarthrosis will probably never be entirely effective until the etiology has been determined. Osteosynthesis by bone-grafting still offers the principal means of attacking the problem. It is the author's belief that improvements in surgery, in bone-grafting, in bone-graft material, and in fixation, protection during the follow--up period, and early reinforcement of weak grafts will offetr greater hope of successful treatment and will reduce the number of failures and amputations.