Abstract
Among various factors that affect fracture healing, the condition of the periosteum and dynamic effects have remained obscure. Fracture healing requires callus formation and subsequent bone maturation, which are considered separate processes. In this study, we performed a histomorphologic investigation to clarify the role of the periosteum and its relation to mechanical stimulation in the fracture healing process. We studied callus formation in the initial stage of fracture healing. Transverse fractures were made in the tibia of rabbits with a saw and repaired with a plate. Rabbits were divided into three groups : 1) a no periosteum group (NP group), 2) a preservation of periosteum, non-invasive group (PNI group), and 3) a preservation of periosteum, invasive group (PI group) . We also prepared the following two subgroups : 1) a rigid stability group and a 2) nonrigid (micromovement) group. A control group was prepared in which a fracture was made manually under anesthesia and fixed with gypsum. In this study, better callus formation was observed in the PI and PNI groups than in the NP group. Callus formation was promoted in the group given micro-movement mechanical stimulation. Callus formation occurred earlier in the group in which detached, invasive stimulation was applied to the periosteum. Callus formation was promoted in the gypsum-fixation group due to mechanical stimulation and sufficient invasive stimulation. In all groups, only woven bone formation was seen, but bone maturation was not seen. In conclusion, callus formation is promoted by various periosteal stimuli, including mechanical stimulation through micromovement and invasive stimulation. In bone maturation, the remodeling of callus is promoted by another process (dynamization) .
