Periosteal expansion osteogenesis using a tubular dynamic frame device: An experimental study in rats

Abstract Periosteal expansion osteogenesis (PEO) is a technique for augmenting bone by creating a gradual separation between the bone and periosteum. This study assessed PEO‐induced bone formation around the femurs of rats using a dynamic frame device (DFD), consisting of a shape memory membrane made of polyethylene terephthalate (PET) formed into a tubular shape. The DFDs, consisting of a PET membrane coated with hydroxyapatite (HA)/gelatin on the bone‐contact surface, were inserted between the periosteum and bone of the femurs of rats. In the experimental group, DFDs were suture‐fixed to the femur with 4–0 Vicryl Rapid; in the control group, 4–0 silk thread was used for fixation. Five rats per group were euthanized at intervals of 3, 5, and 8 weeks postoperatively. Bone formation was evaluated via micro‐CT imaging, histomorphometry, and histological analysis. Morphological analysis revealed new bone between the femur and the periosteum, expanded by the DFD, in all groups. The mean values of new bone were 0.30 mm² proximally, 0.18 mm² centrally, and 0.82 mm² distally in the control group, compared to 1.05 mm² proximally, 0.27 mm² centrally, and 0.84 mm² distally in the experimental group. A significant difference in new bone was observed in the proximal region of the experimental group. Histological examination showed that a single layer of newly formed neoplastic bone was noted on the cortical bone surface across all sites. The proximal portion displayed a bone marrow cavity at the center, encircled by a thick bone cortex with a layered structure. New bone formation was notable between existing cortical bone and the periosteum, particularly at both ends of the DFD. The use of PET in PEO was a viable option for achieving ideal bone morphology.