两种改性可吸收界面螺钉重建前交叉韧带的生物力学研究

A Biomechanical Study of Two Modified Dioabsorbable Interference Screw for Fixation of Soft Tissue Grafts in Anterior Cruciate Ligament Reconstruction

目的探索两种改性可吸收界面螺钉聚乳酸/羟基磷灰石/α-Fe2O3(PLLA/HA/α-Fe2O3)和聚乳酸-聚乙二醇/羟基磷灰石(PLLA-PEG/HA)重建前交叉韧带(anterior cruciate ligament,ACL)早期是否能满足对移植物固定的初始力学要求。方法猪胫骨及游离的猪伸趾肌腱被随机分为3组,每组包括8个胫骨及8个伸趾肌腱,分别应用PLLA/HA/α-Fe2O3、PLLA-PEG/HA及临床使用聚乳酸/羟基磷灰石(Bio RCI-HA,Smith&Nephew,USA)三种界面螺钉对胫骨端移植物进行挤压固定。移植物固定完成后对三组实验样本实施生物力学测试,包括最大载荷、刚度和失败模式。结果最大载荷:Bio RCI-HA组为(483.4±103.8)N,PLLA/HA/α-Fe2O3组为(456.0±102.0)N,PLLA-PEG/HA组为(445.7±90.1)N,三组最大载荷差异无统计学意义。抗拉刚度:Bio RCI-HA组(48.0±6.7)N/mm>PLLA-PEG/HA组(40.7±6.7)N/mm和PLLA/HA/α-Fe2O3组(41.2±4.6)N/mm,前者抗拉强度较后两者差异有统计学意义。失败模式:所有样本测试失败模式均为移植物滑出,并无出现移植物撕裂或者固定装置损坏发生。结论改性界面螺钉PLLA/HA/α-Fe2O3、PLLA-PEG/HA在重建猪ACL中能满足生物力学要求。

Objective To evaluate the biomechanical properties of soft-tissue grafts reconstructed anterior cruciate ligament（ ACL） with two modified bioabsorbable interference screws,Poly-L-lactic acid / hydroxyapatite / α-Fe2O3（PLLA/HA/α-Fe2O3） screw and Poly-L-lactic acid-polyethylene glycol/hydroxyapatite（ PLLA-PEG/HA） screw. Methods Porcine tibia and hoof extensor tendons were divided into 3 matched groups with 8 tibia and 8 extensor tendons in each group. PLLA / HA / α-Fe2O3screws、PLLA-PEG / HA screws and poly-L-lactic acid and hydroxyapatite（ Bio RCI-HA,Smith Nephew,USA） screws were used for tibial fixation in soft-tissue grafts ACL reconstruction. All specimens were subjected to tensile loading,including load to failure,stiffness and mechanism of failure recorded. Results The mean load to failure were（ 483. 4 ± 103. 8） N in Bio RCI-HA screw group,（456. 0 ± 102. 0） N in PLLA / HA / α-Fe2O3 screw group,（ 445. 7 ± 90. 1） N in PLLA-PEG / HA screw group. No statistically significant differences were noted in mean load to failure. The mean stiffness：Bio RCI-HA screw（48. 0 ± 6. 7） N/mm PLLA-PEG/HA screw（40. 7 ± 6. 7） N/mm and PLLA/HA/α-Fe2O3screw（41. 2 ± 4. 6） N / mm.Bio RCI-HA screws showed a greater stiffness than PLLA-PEG / HA screws and PLLA / HA / α-Fe2O3 screws respectively. Mechanism of failure recorded：no graft failure or fixation failure was observed in either testing. When testing for pull out failure,all grafts were slipped out. Conclusion In this porcine model,PLLA-PEG / HA screws and PLLA / HA / α-Fe2O3 screws provided comparable biomechanical strength with Bio RCI-HA screw.