BONE-FORMATION BY VASCULARIZED PERIOSTEAL AND OSTEOPERIOSTEAL GRAFTS - AN EXPERIMENTAL-STUDY IN RATS

The osteogenic capacity of vascularized periosteal and osteoperiosteal grafts was investigated in 82 Wistar rats about 8 weeks old. The periosteal flaps, pedicled on the descending genicular artery, were taken by stripping the lower third of the femur. In the right hindleg, the grafts were made with periosteum only, while in the left hindleg, the periosteal flaps were associated with cancellous bone. The animals were divided into two groups of 41. In group I, both the periosteal and osteoperiosteal grafts were placed in contact with cortical bone, and in group II, the grafts were buried in muscle. Subgroups of 8 animals were killed after 1, 2, 4, 8, and 16 weeks postoperatively. The grafted region was evaluated radiographically, macroscopically, and histologically. Membranous ossification was the main source of bone formation. Osteo-periosteal grafts produced a greater amount of new bone than periosteal ones. There was evidence that the contact of the graft with living cortical bone favored bone formation.