Lundberg W R, Lewis J L, Smith J J, Lindquist C, Meglitsch T, Lew W D, Poff B C
Department of Orthopaedic Surgery, University of Minnesota, Minneapolis 55455, USA.
J Orthop Res. 1997 Sep;15(5):645-51. doi: 10.1002/jor.1100150503.
An existing goat model was used to measure in vivo graft forces during walking, to determine if the forces set at surgery change over time under the same external load and if the forces in the graft during in vivo function can be dictated by the forces set at surgery. The anterior cruciate ligament was reconstructed in 12 goats with use of a composite graft consisting of a bone-patellar tendon-bone autograft and a synthetic augmentation segment. The forces in the graft segments were established intraoperatively by a force-setting technique. In five animals, the tendon segment was set to carry 90% of the total graft force, and in the seven other animals, the augmentation segment was set to carry 90% of the total force. The total graft force was the same in all animals. Graft forces due to anterior tibial loads of 67 N were measured before and after fixation and 6 weeks after surgery with the use of buckle transducers mounted extra-articularly over the anterior tibia. They were also measured during straight, level walking at 6 weeks. The forces changed significantly from just after surgery to 6 weeks later, such that the initially set load-sharing was eliminated by 6 weeks. At 6 weeks, a relatively smooth gait had been achieved, and the maximum total graft force in each animal during walking averaged 35 N and was of similar magnitude to forces generated by the anterior tibial loads of 67 N with the animal anesthetized. After fixation, forces in the tendon graft segments were significantly different between the group with high set forces and that with low set forces. At 6 weeks, when functional joint loads were approaching normal levels, the graft segment forces for the two groups were not significantly different. Load-sharing between tendon and augmentation segment and load in the tendon segment at 6 weeks could not be dictated at surgery.
使用现有的山羊模型来测量行走过程中的体内移植物受力情况，以确定手术时设定的力在相同外部负荷下是否会随时间变化，以及体内功能期间移植物中的力是否可由手术时设定的力决定。对12只山羊进行前交叉韧带重建，使用由骨 - 髌腱 - 骨自体移植物和合成增强段组成的复合移植物。术中通过力设定技术确定移植物各段的力。在5只动物中，腱段设定为承担总移植物力的90%，在另外7只动物中，增强段设定为承担总力的90%。所有动物的总移植物力相同。使用安装在前胫骨关节外的扣式传感器，在固定前后以及术后6周测量67 N前胫骨负荷引起的移植物力。还在术后6周直线水平行走期间进行测量。从刚手术后到6周后，力发生了显著变化，以至于最初设定的负荷分担在6周时消失。在6周时，已实现相对平稳的步态，每只动物行走期间的最大总移植物力平均为35 N，与动物麻醉时67 N前胫骨负荷产生的力大小相似。固定后，高设定力组和低设定力组的腱移植物段中的力有显著差异。在6周时，当功能性关节负荷接近正常水平时，两组的移植物段力没有显著差异。手术时无法决定6周时腱段与增强段之间的负荷分担以及腱段中的负荷。
