Beynnon B D, Johnson R J, Fleming B C, Renström P A, Nichols C E, Pope M H, Haugh L D
Department of Orthopaedics and Rehabilitation, McClure Musculoskeletal Research Center, University of Vermont College of Medicine, Burlington 05405.
J Bone Joint Surg Am. 1994 Apr;76(4):520-31. doi: 10.2106/00004623-199404000-00006.
Many investigators who have studied the mechanical behavior of anterior cruciate-ligament grafts have attributed the increase in anterior translation of the tibia relative to the femur (an increase in the anterior laxity of the knee joint) to the temporal changes in the material behavior (strength and elastic properties) of the graft that occur throughout the process of remodeling. However, with the onset of motion of the joint, it is unclear whether the repeatable mechanical behavior of the graft remains unchanged immediately after fixation, if the fixation slips, or if the length of the graft changes and produces an increase in anterior translation of the tibia relative to the femur. It is also unknown if procedures performed by different surgeons, using similar graft material and similar operative techniques, can produce similar mechanical behavior of the graft, or if the behavior of the graft is similar to that of the normal anterior cruciate ligament. In an effort to address these questions, two surgeons performed a reconstruction of the anterior cruciate ligament on ten patients each (groups 1 and 2) with use of a bone-patellar ligament-bone graft. Immediately after fixation of the graft, a Hall-effect transducer was implanted to measure the changes in the length of the mid-substance of the graft while the knee was moved through twenty cycles of passive flexion-extension. Unlike the length pattern of the normal anterior cruciate ligament, the length pattern of the graft changed during the initial cycles of passive motion of the knee. We defined this phenomenon as the cyclic response of the graft and characterized it by calculation of the changes in the length of the graft at fixed positions of the knee across the multiple cycles of passive motion. In some patients, the length of the graft increased through the initial passive-motion cycles, while in others, it decreased. With the knee nearly extended, the predicted increase in anterior translation of the tibia relative to the femur, resulting from the increase in the length of the graft, was a maximum of 1.0 millimeter. This indicates that increases in anterior translation of the tibia relative to the femur can occur immediately after reconstruction of the anterior cruciate ligament and that changes in the length of the graft occur after fixation at loads that are less than the ultimate failure load of the graft or of the fixation.(ABSTRACT TRUNCATED AT 400 WORDS)
许多研究前交叉韧带移植物力学行为的研究者将胫骨相对于股骨向前平移的增加（膝关节前侧松弛度增加）归因于移植物在整个重塑过程中材料行为（强度和弹性特性）随时间的变化。然而，随着关节运动的开始，尚不清楚移植物在固定后、固定发生滑动时或移植物长度发生变化并导致胫骨相对于股骨向前平移增加时，其可重复的力学行为是否立即保持不变。同样未知的是，不同外科医生使用相似的移植物材料和相似的手术技术进行的手术，是否能产生相似的移植物力学行为，或者移植物的行为是否与正常前交叉韧带的行为相似。为了回答这些问题，两位外科医生分别对10名患者（第1组和第2组）使用骨-髌腱-骨移植物进行了前交叉韧带重建。移植物固定后，立即植入一个霍尔效应传感器，在膝关节进行20个被动屈伸周期时测量移植物中间部分的长度变化。与正常前交叉韧带的长度模式不同，移植物的长度模式在膝关节被动运动的初始周期中发生了变化。我们将这种现象定义为移植物的周期性反应，并通过计算在多个被动运动周期中膝关节固定位置处移植物长度的变化来对其进行表征。在一些患者中，移植物的长度在初始被动运动周期中增加，而在另一些患者中则减少。在膝关节几乎伸直时，由于移植物长度增加导致的胫骨相对于股骨向前平移的预测最大增加量为1.0毫米。这表明在前交叉韧带重建后，胫骨相对于股骨向前平移的增加可能会立即发生，并且移植物长度的变化在固定后发生，此时的负荷小于移植物或固定的最终破坏负荷。（摘要截选至400词）
