复合腱-骨固定的生物力学及形态学研究

A biomechanical and morphological study on composited tendon-bone fixation

[目的]探讨不同固定方式对前交叉韧带重建中股骨隧道内移植物的影响。[方法]成年猪膝关节64个,以足部肌腱为移植物模拟前交叉韧带重建股骨侧腱-骨固定,固定方式随机分为5组,分别采用7 mm×23 mm界面螺钉固定(A组)、6 mm×23 mm界面螺钉固定(B组)、聚酯缝线4孔微钢板股骨外口固定(C组)、Endobutton固定(D组)和B与C固定组合(E组),进行生物力学测试并观察股骨隧道内口移植腱横截面积及厚度。[结果]持续施加200 N的轴向牵拉力条件下,A、B、E组轴向位移均为0 mm,C组的轴向位移为(5.51±0.53)mm,D组的为(5.49±0.51)mm;C组和E组移植物轴向位移差异有统计学意义(P<0.05)。最大损毁强度A组为(350.62±17.81)N,B组为(260.71±18.44)N,C组为(650.50±24.34)N,D组为(565.66±21.63)N,E组为(800.53±30.21)N,组间比较差异有统计学意义(F=291.352,P<0.01)。移植物内口横截面形态,A组的横截面呈"新月状",足印处移植物最大宽度为1 mm,横截面积为(10.06±0.18)mm^2;B组呈近似"满月状",足印处宽度为8 mm,面积为(38.16±0.32)mm^2;C组呈"满月状",足印处宽度为8 mm,面积为(40.02±0.21)mm^2;E组呈近似"满月状",足印处厚度为8 mm,面积为(38.86±0.29)mm^2。A、E组间比较差异有统计学意义(F=290.568,P<0.01)。此外,A组的挤压程度较重,B组较轻,C组的无挤压,E组同B组。[结论]复合固定技术不仅提供了足够的移植物初始固定强度,还有效避免了"雨刷和蹦极效应",减少了螺钉对肌腱的挤压切割,有利于移植物骨愈合和足印重建。

[Objective] To explore the effects of different fixation methods on anterior cruciate ligament reconstruction at femoral internal orifice in terms of biomechanics and morphology. [Methods ] Models of tendon graft to bone tunnel fixation were mimicked in 64 fresh adult pig knees using foot tendons as graft. The graft in the femoral tunnel were fixed by 5 techniques randomly, including a 7x23 mm interference screw （ Group A）, a 6x23 mm interference screw （Group B）, polyester suture and microplate outside femoral cortex （Group C）, endobutton （Group D） and combined B with C technique （ Group E）. Biomechanical tests and morphological measurement on the femoral internal orifice were conducted. [Results] Axial dis- placements at the femoral internal aperture was measured 0 mm in the Groups A , B and E, while （5.51±0.53） mm in the Group C and （5.49±0.51） mm in the Group D respectively, there was a statistical difference between the Group C and Group E （P〈0.05） . The maximal failure load was documented （350.62±17.81） N in the Group A, （260.71±18.44） N in the Group B, （650.50±24.34） N in the Group C, （565.66±21.63） N in the Group D and （800.53±30.21） N in the Group E, with a statistical difference among the groups （F=291.352, P〈0.01）. Regarding to the graft - tunnel interface morphology at the femoral aperture inside, the cross section of tendon graft was crescent-like with the widest transvers diameter of 1 mm and total area of （10.06±0.18） mm^2 in the Group A, near full moon-like with corresponding 8 mm and （38.16±0.32） mm^2 in the Group B, full moon-like with 8 mm and （40.02±0.21） mm^2 in the Group C, and full moon-like with 8 mm and （38.86±0.29） mm^2 in the Group E. There were significant differences in cross sectional area among the groups （F=290.568, P〈 0.01）. The extent of tendon compression was serious in the Group A, less serious in the Group B, none in the Group C and less serious in the Group E. [Conclusion] The modified composited fixation not only provides enough initial fixation strength, but also avoids the ＂effect of bungee jumping＂ and ＂effect of windshield wiper＂, diminishes squeezing and cutting tendon graft from the screw, so it will be benefit for bone graft healing and footprints of reconstruction.