Transplantation of osteoblast-like cells to the distracted callus in rabbits

We carried out limb lengthening in rabbits and VV then transplanted osteobl ast-like cells derived from the tibial periosteum to the centres of distrac ted callus immediately after distraction had been terminated. Two weeks lat er the transaxial area ratio at the centre of the distracted callus and the bone mineral density (BMD) were significantly higher in the transplanted g roup, by 21% and 42%, respectively, than in the non-injected group or the g roup injected with physiological saline (p < 0.05). Callus BMD as a percent age of density in uninvolved bone was also significantly higher in the tran splanted group (p < 0.05) than in the other two groups, by 27% and 20% in t he second and fourth weeks, respectively (p < 0.05). Mechanically, the call us in the transplanted group tended to be stronger as shown by the three-po int bending test although the difference in fracture strength was not stati stically significant. Our results show that transplantation of osteoblast-like cells promotes mat urity of the distracted callus as observed at the second and fourth weeks a fter lengthening. The method appears promising as a means of shortening the consolidation period of callus distraction and decreasing complications du ring limb lengthening with an external fixator.