Case report of a central midshaft osteosarcoma of the femur, treated conservatively under Rosen procedure. Bone resection was followed by reconstruction with a deep frozen (-196 degrees) conserved massive homograft, fixed by an interlocked Kuntscher's nail. The purpose of this paper is to expose the advantages of this type of fixation, V.S. conventional nails, or plates. X-Ray showed a bridging bone spindle between host and graft cortical bone, induced by initial stability of the nail, and a rapid fusion after secondary dynamisation of the nail, by removing one screw. We obtained an early functional recovery and a complete and rapid autonomy necessary to allow social and school reinsertion, whatever should the medium or long term presumed survival be.