Healing of membranous and long bone defects. An experimental study in growing rabbits.

Different isolation models have been used for qualitative and quantitative studies on the individual roles of periosteum, cortical bone, endosteum and bone marrow in the repair of long bone defects. Corresponding skull defects were studied to evaluate also the dural osteogenetic capacity. A total of 53 operations were performed on the tibia and skull of 33 growing rabbits. The animals were killed 10-12 weeks after surgery. Ordinary rough histological methods were used for studying bone formation, and quantitative estimates were made using serial sections. The cortex, endosteum and bone marrow were demonstrated to play a minor part in the healing of tibial defects. Periosteum, on the other hand, had the most potent healing capacity. Calvarial periosteum, however, was found to be less bone producing and in that respect not to be superior to the dura. For a complete bony restoration combined periosteal and dural bone formation is necessary, also regarding the structural normalization.