Studies in the Repair of Bone

Conclusions

1. Epiphyseal tissue will regenerate new bone in immature dogs. 2. Cancellous bone will bridge bony defects without the aid of periosteum. 3. Periosteum will hasten callus formation of cancellous bone grafts. 4. Free bone marrow and endosteum will bridge bone defects without the aid of periosteum with a rapid forming callus. 5. The clinical use of bone marrow and endosteum is suggested in bone grafting.

The supremacy accorded the periosteum in osteogenesis has led to an almost complete neglect of the rôle played by other bone elements. Work on epiphyseal tissue has indeed been very scant, but there is both clinical and experimental evidence that cancellous bone plays an important rôle in bone repair, while the osteogenic properties of bone marrow and endosteum though often mentioned have been little studied.

Epiphyseal Tissue Transplants. A set of experiments were carried out on 6 immature dogs. A quarter inch extraperiosteal resection of each fibula was filled on one side with ground epiphyseal tissue while on the control side the defect was filled with ground whole bone. The defects were bridged across in each case. The epiphyseal tissue invariably produced a large thick spongy callus. Serial slides of X-rays were presented to illustrate this callus at different stages of development, Fig. 1.

Cancellous Bone Transplants. Experiments were done on 5 adult dogs. Cancellous bone was removed from the condyle of the femur and transplanted into extraperiosteal and subperiosteal defects of the 2 fibulae respectively on each dog. These defects bridged across in each case even where there was no existing periosteum. Slides of serial X-rays were presented to illustrate how rapidly cancellous bone grafts regenerate new bone. (Fig. 2.) On the side of the subperiosteal resections the favorable presence of intact periosteum is well illustrated in a more rapid regeneration.

Bone Marrow and Endosteal Transplants. The next group of experiments was carried out on 6 adult dogs. Each fibula was resected extra-periosteally. On each side the defect was filled with endosteum and bone marrow removed from the tibia with a small curette. No regeneration occurred on the control side where no grafts were placed, while on the side containing endosteum and bone marrow rapid and complete reformation of dense bone occurred. Slides of serial X-rays were shown to illustrate this rapid osteogenesis. (Fig. 3a.) A photomicrograph was presented to show the new bone callus. (Fig. 3b.)