Pathological study of bone lengthening for bone defect resulted from gunshot wound / 中华骨科杂志

ABSTRACT

Objective To investigate the pathological changes of bone in situ lengthening for the gunshot bone defect, and to discuss the practical feasibility and biological basis of bone lengthening in the conditions of periosteum damage. Methods The 38 canines were randomly distributed into two groups and sustained the same gunshot bone defect in the mid femoral diaphysis. In one group, the femur were stabilized with Bastiani external fixator and 2 weeks later the fractured limb with fixation were lengthened 2-4 times per day at a speed of 0.5-1 mm/d until the normal length was reached. The control group only had external fixation without lengthening. 3, 6 and 12 weeks after injury, the canines were given 99mTc MDP and got radionuclide examination under SPECT (ADAC company, USA.). Pathological and X ray observation were carried out at 1, 2 ,3 ,6 and 12 weeks respectively after injury for comparison between two groups. Results The X ray measurement showed that the length of callus distraction in the bone lengthening group increased by (2.82?0.94)cm and the relative lengthening of bone is 19.3% (15.8%-21.4% ), compared with normal femur on the same X ray film. The count of radionuclide increased gradually at the region of bone defect in the lengthening group. While in the fracture ends, no significant difference was found in the development pattern through each radionuclide observation phase between two groups. The main mode of osteogenesis was endochondral ossification and the bone defect area was enriched by chondrocyte in the bone lengthening group. Conclusion There are no obvious negative influence on bone turnover and local blood flow in the bone lengthening for gunshot bone defect. The remained periosteum and bone fragment under gunshot injury may have important role in the progression of osteogenesis. The neogenetic capillary provided not only blood supply for healing of bone but also source of osteocyte for bone lengthening in the case of the periosteum and blood circulation damaged with gunshot wound.