Impact Response Analysis of Patella-Patellar Tendon-Tibial Tuberosity Complex

通过髌骨-髌骨肌腱-胫骨结节（PTT）复合物的冲击载荷衰减已经研究了胫骨结节中生长软骨骨化的进展。本研究使用的材料是PTT复合物和髌骨肌腱，取自胫骨结节骨化三个不同阶段的猪后腿。它们的骨化阶段由体重（20,100和200kgf）表示。采用split-Hopkinson压杆技术在室温下对PTT复合物和髌骨进行冲击拉伸试验。在PTT和髌骨肌腱的两项试验中，在施加冲击载荷之前，对它们施加预拉伸载荷。PTT复合物的实验载荷传输率随预紧力的增加而增加，与体重无关。较大的体质量或高度骨化的标本表现出较低的负荷传动比。髌骨肌腱杨氏模量随关节前张力的增加及胫骨粗隆处生长软骨骨化的进展未见明显变化。考虑到PTT配合物各截面的材料性能和几何形状随其生长而变化，从理论上分析了不同骨化阶段PTT配合物的冲击响应，并考虑应力波的衰减特性来预测载荷传递比和最大应变截面。为此，在x射线图像和骨密度测量的帮助下，建立了代表配合物力学行为的简单模型，并基于一维波传播理论进行了分析。还对冲击响应分析中使用的相同模型进行了静态分析。冲击反应分析能很好地预测生长过程中不同阶段损伤的位置，而静态分析不能预测这种临床情况。少

Attenuation of impact load through patella-patellar tendon-tibial tuberosity (PTT) complex has been investigated with respect to the progress of ossification of growing cartilage in tibial tuberosity. Materials used in this study were PTT complexes and patellar tendons taken from porcine hind legs with three different stages of ossification of tibial tuberosity. Their stages of ossification were represented by body weight (20,100 and 200kgf). Impact tensile tests on PTT complexes and patellar tendons were performed at room temperature using the split-Hopkinson pressure bar technique. In both tests on PTT and patellar tendons pretensile loads were applied to them just before an application of impact load. The experimental load transmission ratio of PTT complexes increased with an increase of pretension, independent of body weight. Larger body weight, or highly ossified specimen appeared to show lower load transmission ratio. Significant change in Young's modulus of patellar tendon with … More an increase of pretension as well as the progress of ossificationt of growing cartilage in tibial tuberosity was not found. Since material properties and geometry of each section of the complex were considered to be varied with its growth, the impact responses of PTT complexes with different stages of ossification were theoretically analysed with the consideration of attenuation property of stress wave for the prediction of load transmission ratio as well as the section subjected to maximum strain. To this end, simple models representing mechanical behaviour of the complexes were made with the assistance of their X-ray images and BMD measurements, and the analyses were performed based on the one-dimensional wave propagation theory. Static analyses of the same models as used in the impact response analyses were also performed. The impact response analyses well predicted the location of injuries in different stages of growing process, while static analyses could not predict such clinical situation. Less