Nyland John, Kocabey Yavuz, Caborn David N M
Division of Sports Medicine, Department of Orthopaedic Surgery, University of Louisville, Louisville, Kentucky 40202, USA.
Arthroscopy. 2004 Apr;20(4):379-84. doi: 10.1016/j.arthro.2004.01.026.
The purpose of this study was to evaluate the relationship between insertion torque and the biomechanical characteristics of soft tissue tendon graft tibia fixation with a bioabsorbable interference screw.
Biomechanical study.
Doubled tibialis anterior allografts (n = 20, length = 100 mm, diameter = 9 mm) prepared for anterior cruciate ligament (ACL) reconstructions were divided into 3 groups. Maximum insertion torque was measured as grafts were fixed by the same surgeon with a 10-mm diameter, 35-mm long screw in a 7-mm diameter tunnel (dilated to 9 mm) created in either 0.16 or 0.32 g/cm3 dense synthetic bone or cadaveric tibiae (0.84 +/- 0.15 g/cm2). Tensile testing to construct failure was then performed.
All constructs failed by tunnel pullout. Higher density synthetic bone had greater load at failure than lower density synthetic bone (486.6 +/- 83.8 v 271.6 +/- 52.6 N, P <.0001) and a slightly greater proportion of variance could be explained in synthetic bone (R2 = 0.74, P <.0001) than in cadaveric tibiae (R2 = 0.64, P =.017). Higher density synthetic bone displayed greater stiffness than lower density synthetic bone (68.1 +/- 21.6 v 37.7 +/- 11.2 N/mm, P =.012) and a higher proportion of variance could be explained in cadaveric tibiae (R2 = 0.72, P =.008) than in synthetic bone (R2 = 0.48, P =.012). Greater insertion torque levels were seen in higher density synthetic bone (2.97 +/- 0.35 v 1.24 +/- 0.06 Nm, P <.0001) than in lower density synthetic bone, and a higher proportion of variance could be explained in synthetic bone (R2 = 0.94, P <.0001) than in cadaveric tibiae (R2 = 0.74, P =.006).
Strong relationships were evident between insertion torque, bone mineral density (BMD) and load to failure across constructs. Differences between the synthetic bone groups and cadaveric tibiae, however, suggest the influence of mixed cortical and cancellous bone, nonuniform structural patterning, and differing BMD levels and distributions in the cadaveric tibiae.
Soft tissue graft tibial tunnel fixation is directly related to insertion torque and BMD. Synthetic models with mixed bone characteristics are needed to more accurately depict human tibiae during fixation testing.
本研究旨在评估使用生物可吸收干涉螺钉进行软组织肌腱移植胫骨固定时，插入扭矩与生物力学特性之间的关系。
生物力学研究。
为前交叉韧带（ACL）重建准备的双侧异体胫骨前肌移植物（n = 20，长度 = 100 mm，直径 = 9 mm）被分为3组。由同一位外科医生在直径为7 mm（扩张至9 mm）的隧道中，使用直径10 mm、长35 mm的螺钉固定移植物时，测量最大插入扭矩，该隧道在密度为0.16或0.32 g/cm³的致密合成骨或尸体胫骨（0.84±0.15 g/cm²）中创建。然后进行拉伸测试直至结构破坏。
所有结构均因隧道拔出而失效。较高密度的合成骨在破坏时承受的载荷比较低密度的合成骨更大（486.6±83.8对271.6±52.6 N，P <.0001），并且合成骨中可解释的方差比例（R² = 0.74，P <.0001）比尸体胫骨（R² = 0.64，P =.017）略高。较高密度的合成骨比较低密度的合成骨表现出更大的刚度（68.1±21.6对37.7±11.2 N/mm，P =.012），并且尸体胫骨中可解释的方差比例（R² = 0.72，P =.008）比合成骨（R² = 0.48，P =.012）更高。较高密度的合成骨比较低密度的合成骨具有更高的插入扭矩水平（2.97±0.35对1.24±0.06 Nm，P <.0001），并且合成骨中可解释的方差比例（R² = 0.94，P <.0001）比尸体胫骨（R² = 0.74，P =.006）更高。
插入扭矩、骨矿物质密度（BMD）与各结构的破坏载荷之间存在明显的强关系。然而，合成骨组与尸体胫骨之间的差异表明，尸体胫骨中皮质骨和松质骨混合、结构模式不均匀以及BMD水平和分布不同的影响。
软组织移植物胫骨隧道固定与插入扭矩和BMD直接相关。需要具有混合骨特征的合成模型，以便在固定测试期间更准确地描绘人体胫骨。
