| Objective:Treat cadaveric femur with inter-locking intramedullary nail fixation, so as toinvestigate the anatomy and biomechanics, discuss the effect of micromovement on thebone union of different femoral shaft fracture section after fixation, look for newinfluencing factors that would result in delayed union or nonunion after intramedullary nailfixation of femoral shaft fracture.Methods:Make a coronal bone fracture model of the middle third and lower third of femoralshaft with cadaveric femoral shaft samples. Treat cadaveric femur with inter-lockingintramedullary nail fixation. Measure the deformation value and draw theforce-deformation curve of distal bone one centimeter away from fracture line afterfixation under outer force respectively from front, back, left and right.Results:The middle third of femoral shaft has a lower micromovement value on average, withfront (0.13±0.01) mm, back (0.18±0.01) mm, left (0.11±0.03) mm, right (0.11±0.03) mm.Thereby we could conclude that inter-locking intramedullary nail fixation of the middlethird of femoral shaft features stable biomechanics and better bone union. Themicromovement value of the lower third of femoral shaft increases apparently in contrastto the middle third, with front (0.81±0.06) mm, back (0.59±0.04) mm, left (1.13±0.10) mm,right (2.20±0.14) mm. Hence we could reach a conclusion that inter-locking intramedullarynail fixation of the lower third of femoral shaft has an unstable biomechanics which wouldlater result in delayed union or nonunion. To compare the middle third with the lower third, there is an obvious difference on four directions with significance statistically (P <0.05).Conclusions:The investigation of anatomy and biomechanics shows that the lower third of femoralshaft after inter-locking intramedullary nail fixation has a higher probability of developingbone delayed union or nonunion in contrast to the middle third. |
PDF Full Text Request