Repair of bone transplant fractures.

Fresh autogenous-bone transplant fractures in rabbits have the capacity to unite as early as two weeks in more than two-thirds of the animals. Some of the surface cells of the transplants appeared to survive and proliferate to produce new bone. The graft replacement occurred by creeping substitution. The transplants were well tolerated by host tissues. Graft fracture healing in fresh homogenous transplants was delayed by several weeks, and less than one-third of the fractures united. Marked absorption of the fresh homogenous implant predominated prior to ossification, if any. Fresh and frozen homogenous transplants induced a cellular inflammatory reaction similar to that described for other homogenous graft tissue. Frozen, freeze-dried, and merthiolate-preserved homogenous-bone implants produced little osteogenic stimulus in the host tissues. Graft fractures usually do not unite. These grafts were replaced very slowly, if at all, by fibrous tissue first, and then by bone. Fresh autogenous-bone transplants are far superior to any other type of bone transplant. The repair capacity of fresh autogenous grafts as measured by graft fracture healing exceeds that of fresh, frozen, freeze-dried, merthiolate-preserved homogenous grafts, or frozen and boiled autogenous grafts. Fresh homogenous grafts exhibited the next best osteogenic-repair capacity; however, the marked inflammatory incompatibility reaction to the homogenous bone may be detrimental.