微创内固定系统与动力髁螺钉固定股骨远端不稳定骨折的生物力学研究

摘要

目的 对比微创内固定系统(LISS)和动力髁螺钉(DCS)固定股骨远端不稳定骨折的生物力学性能.方法 选取13对福马林防腐尸体股骨,制作AO/OTA 33-C2型骨折模型,每对股骨左右侧随机使用HSS或DCS固定.然后进行轴向压缩实验、扭转实验及循环压缩实验,分别测量股骨的轴向位移、扭转角度以及循环载荷下的可逆和不可逆位移,并记录轴向载荷、扭转载荷以及循环载荷.结果 HSS的轴向抗压刚度为(303.93±75.81)N/mm,优于DCS[(282.59±71.99) N/mm],差异有统计学意义(P＜0.01);LISS的抗扭转刚度为(1.59±0.56) Nm/deg,DCS为(1.28±0.48) Nm/deg,两组差异无统计学意义(P＞0.05);LISS组股骨的可逆位移[(2.71 ±1.26) mm]以及不可逆位移[(2.43±2.19) mm]均小于DCS组[(3.29 ±2.30) mm和(3.20 ±2.35) mm],差异有统计学意义(P＜0.05).结论 在固定股骨远端不稳定骨折方面,HSS的生物力学性能优于DCS,但是两者的抗扭转刚度相当.%Objective To compare biomechanical properties of less invasive stabilization system (LISS) and dynamic condylar screw (DCS) in fixing unstable distal femoral fracture,and thus to provide a theoretical basis for clinical treatment.Methods Thirteen pairs of formalin preservative corpse femur were chosen to make AO/OTA 33-C2 fracture model,and LISS and DCS were used to fix the right or left side of each pair of femur randomly.Then axial compression test,torsion test,and cyclic compression test were conducted to measure the axial displacement of the femur,the twist angle,and reversible and irreversible shift under cyclic loading,and axial load,torsional load,and cyclic load were recorded.Results The axial compressive stiffness of LISS [(303.93 ±75.81) N/mm] is better than that of DCS [(282.59 ±71.99) N/mm],the difference is statistically significant (P ＜ 0.01);The torsional stiffness of LISS is (1.59 ±0.56) Nm/deg,and DCS is (1.28 ±0.48) Nm/deg,there is no statistical difference (P ＞0.05);the reversible displacement and irreversible displacement of the femur in LISS group [(2.71 ± 1.26),(2.43 ±2.19) mm] is less than that of DCS group [(3.29 ±2.30),(3.20 ±2.35) mm],the difference is statistically significant (P ＜ 0.05).Conclusion The biomechanics of LISS is better than that of DCS in fixing unstable distal femoral fracture,but much the same on torsional stiffness.