逆行交锁髓内钉与微创内固定钢板修复股骨远端骨折的生物力学性能比较

摘要

背景：目前股骨远端骨折多采用微创内固定系统(LISS)钢板或逆行交锁髓内钉内固定治疗，但两种方法的选择尚有争议，且对其生物力学性能研究尚少。目的：比较逆行交锁髓内钉与LISS钢板置入内固定修复股骨远端骨折的生物力学稳定性。方法：取12根尸体股骨标本，均为男性，X射线摄片排除损伤、骨密度异常及骨病标本。随机分成2组，制成相同标准AO分型A3型髁上骨折模型，分别用LISS钢板和逆行交锁髓内钉内固定。观察股骨标本承受轴向压缩时的抗压刚度和载荷100，300，500 N下的位移值，以及标本承受弯曲载荷时的抗弯强度。结果与结论：①在抵抗轴向变形能力(抗压刚度)方面，LISS钢板大于逆行交锁髓内钉(P<0.05)；在抵抗弯曲变形能力(抗弯强度)方面，逆行交锁髓内钉大于LISS钢板，但差异无显著性意义(P>0.05)；②在100，300，500 N轴向压缩载荷作用下，LISS钢板组的位移均小于逆行交锁髓内钉组(P<0.05)；③生物力学测试结果显示，内固定物置入修复股骨远端骨折时，逆行交锁髓内钉的刚度较低。LISS钢板既具有一定的变形性，使应力能够通过骨传导，又具有较强的刚度，且内固定牢固，可为骨折愈合提供优良的生物学环境，是修复股骨远端骨折的可靠选择。%BACKGROUND:Distal femoral fractures are mainly treated with less invasive stabilization system (LISS) plate or retrograde interlocking intramedul ary nail fixation, but choosing which method is controversial, and studies on their biomechanical properties are few. OBJECTIVE:To compare the biomechanical stability of retrograde interlocking intramedul ary nail and LISS plate fixation in the treatment of distal femoral fractures. METHODS:Twelve male cadaveric femurs were col ected, and the injured, with abnormal bone density and osteonosus specimens were excluded through X-ray examination, fol owed by randomly divided into two groups. Models of AO type A3 supracondylar fracture were prepared, and were fixed with LISS plate and retrograde interlocking intramedul ary nail, respectively. The compressive stiffness and displacement values under axial compression and loading of 100, 300 and 500 N, as wel as the bending strength of the specimens under bending load were observed. RESULTS AND CONCLUSION:(1) The resistance to axial deformation capacity (compressive stiffness) of the LISS plate was superior to the retrograde interlocking intramedul ary nail (P<0.05);while the resistance to bending deformation capacity (flexural strength) of the retrograde interlocking intramedul ary nail was not significantly greater than that of the LISS plate (P>0.05). (2) Under axial compressive loading of 100, 300 and 500 N, the displacement values of LISS plate were significantly less than those of the retrograde interlocking intramedul ary nail (P<0.05). (3) In conclusion, in the distal femoral fracture fixation, the stiffness of the retrograde interlocking intramedul ary nail is low. While the LISS plate not only has certain deformation, but also has strong rigidity with firm internal fixation, which provides excel ent biological environment for fracture healing;thus it is a reliable treatment for distal femoral fractures.