摘要
目的通过有限元分析的方法评价单侧外固定支架联合腓骨移植修复胫骨缺损的初始稳定性。方法选取1名男性志愿者，采用64排CT扫描左下肢，数据导入Mimics软件建立正常的胫、腓骨几何模型。以此为基础，应用单、双根腓骨移植结合外固定支架分别重建4个胫骨缺损的三维模型（缺损长度分别为5、10、15、20cm），采用Hypermesh10．0软件进行网格划分，在Ansysv．11软件中进行有限元分析，测量腓骨植骨块的压应力、骨折块的相对位移和整个有限元模型的应力集中点。结果正常胫骨模型的最大yonMises压应力为8．768MPa，集中区域为胫骨远端1／3。腓骨移植植骨区vonMises压应力和位移随着植骨长度的增加而增加。同样的植骨长度，单腓骨移植植骨区的VOnMises压应力为双腓骨移植的1．37～1．77倍。单腓骨移植的腓骨移植块间位移（IFM）较双腓骨移植大1．13～2．45倍。当单腓骨移植块长度为15cm时，其腓骨移植块IFM为1．28ram；双腓骨移植长度为20cm，其腓骨移植块IFM为0．96mm。模型的最大VOnMises压应力集中于第2,3骨-钉界面。结论在单腓骨移植结合外固定支架的修复胫骨缺损有限元模型上，植骨块长度〉15cm可导致植骨块yonMisesd压应力和IFM过大，胫骨缺损长度〉15cm时应选用双腓骨移植。在选用腓骨移植结合外固定支架修复胫骨缺损时，应特别注意第2、3枚固定针的稳定性。
Objective To study the stabilities of fibular grafts used to reconstruct large tibial defects with unilateral external fixation. Methods The left lower extremity of a healthy male volunteer was scanned by CT. The CT data were imported into software Mimics 11.0 to construct finite element （FE） models of tibia and fibula with normal contour and geometry. Four models of tibial defects of different lengths （5, 10, 15, 20 cm） were reconstructed to simulate unilateral external fixation together with single free vasculafized fibular graft （SFVFG） and double-barrel free vasculafized fibular graft （DBFVFG）. The models were imported into software Hypermesh 10.0 to generate meshes. FE analysis was conducted using software ANSYS v. 11 to measure inter-fragmentary motion （IFM） and yon Mises stress on the fibular graft and locations of maximum von Mises stress in the whole FE model. Results In the model of normal tibia the peak value of yon Mises stress was 8. 768 MPa and the maximal yon Mises stress was located at the distal third of the tibia. Values of yon Mises stress and IFM increased as the length of fibular graft increased in both SFVFG and DBFVFG models. For the same graft length, the yon Mises stress in the SFVFG model was 1.37 to 1.77 times higher than that in the DBFVFG model and the graft IFM in the former 1.13 to 2.45 times higher than that in the latter. When the graft length was greater than 15 cm in the SFVFG model, the graft IFM exceeded 1.28 ram; when the graft length was greater than 20 cm in the DBFVFG model, the graft IFM was only 0. 96 ram. The maximum yon Mises stress in the FE models was frequently located at the second or third pin-bone in- terface. Conclusions The present FE models suggest that because a fibular graft longer than 15 cm may result in excessive von Mises stress and IFM, DBFVFG should be used in reconstruction of a tibial defect larger than 15 cm with unilateral external fixation. The second and third pin-bone interfaces require intensive carefulness from the medical staff in the reconstruction of large tibial defects with unilateral external fixation plus a fibular graft.
出处
《中华创伤骨科杂志》
CAS
CSCD
北大核心
2013年第1期23-27,共5页
Chinese Journal of Orthopaedic Trauma
关键词
胫骨骨折
外固定器
骨移植
有限元分析
Tibial fractures
External fixators
Bone transplantation
Finite element analysis
