髓内持骨动力性髓内钉固定股骨干骨折的三维有限元分析

Three-dimensional finite element analysis on intramedullary controlled dynamic nailing for femoral shaft fracture

背景:交锁髓内钉并发症诸如锁钉弯曲或断裂、退出,钉尾或锁钉孔处再骨折仍然存在,基于此,作者所在课题组设计了一种新型的髓内持骨动力性髓内钉。目的:检验髓内持骨动力性髓内钉设计和强度的合理性与安全性,并就其临床应用和改进提出合理建议。方法:分别建立全股骨及髓内持骨动力性髓内钉固定股骨干横形骨折三维有限元模型。对全股骨模型和骨折模型进行垂直加载及步态分析,了解各模型的应力分布和动力加压特点。结果与结论:在承重载荷下,全股骨模型的股骨颈部及股骨干内外侧缘存在较明显应力集中,骨折模型的应力集中部位位于髓内钉顶端及锁钉周围;步态中,全股骨模型的股骨远端1/2前内侧及股骨颈部存在应力集中,骨折模型的应力集中部位位于髓内钉顶端及锁钉周围;髓内持骨动力性髓内钉有断端动力性加压功能。说明这种髓内持骨动力性髓内钉结构合理,具有良好的生物力学性能。

BACKGROUND：Interlocking intramedul ary nail complications contain nail bent or broken, exit, re-fracture at spiketail or nail hole. Thus, our team designs a novel intramedul ary control ed dynamic nail. 〈br〉 OBJECTIVE：To evaluate the rationality and safety of intramedul ary control ed dynamic nail design and strength, and to give rational proposal for its clinical application. 〈br〉 METHODThe three-dimensional finite element models of composite femur, transverse fractures of the femoral shaft were constructed with intramedul ary control ed dynamic nailing. The stress and strain were detected under vertical loads and gait cycle. 〈br〉 RESULTS AND CONCLUSION：The maximum stress of the intact femur under the compression load was at femoral neck and the medial and lateral aspects of the femoral shaft;while the stresses of fractured femur were at the interface between screw and screw hole. In gait cycle, in case of intact bone, large stresses were found in the distal 1/2 of anteriomedialis of femoral shaft;while the stress distribution in fractured femur was similar with the former. Intramedul ary control ed dynamic nailing has the ability of generating compression between fragments. These suggest that intramedul ary control ed dynamic nailing is rational and good at design and biomechanical properties.