Sakane M, Fox R J, Woo S L, Livesay G A, Li G, Fu F H
Department of Orthopaedic Surgery, University of Pittsburgh, PA 15213, USA.
J Orthop Res. 1997 Mar;15(2):285-93. doi: 10.1002/jor.1100150219.
The anterior cruciate ligament has a complex fiber anatomy and is not considered to be a uniform structure. Current anterior cruciate ligament reconstructions succeed in stabilizing the knee, but they neither fully restore normal knee kinematics nor reproduce normal ligament function. To improve the outcome of the reconstruction, it may be necessary to reproduce the complex function of the intact anterior cruciate ligament in the replacement graft. We examined the in situ forces in nine human anterior cruciate ligaments as well as the force distribution between the anteromedial and posterolateral bundles of the ligament in response to applied anterior tibial loads ranging from 22 to 110 N at knee flexion angles of 0-90 degrees. The analysis was performed using a robotic manipulator in conjunction with a universal force-moment sensor. The in situ forces were determined with no device attached to the ligament, while the knee was permitted to move freely in response to the applied loads. We found that the in situ forces in the anterior cruciate ligament ranged from 12.8 +/- 7.3 N under 22 N of anterior tibial load applied at 90 degrees of knee flexion to 110.6 +/- 14.8 N under 110 N of applied load at 15 degrees of flexion. The magnitude of the in situ force in the posterolateral bundle was larger than that in the anteromedial bundle at knee flexion angles between 0 and 45 degrees, reaching a maximum of 75.2 +/- 18.3 N at 15 degrees of knee flexion under an anterior tibial load of 110 N. The magnitude of the in situ force in the posterolateral bundle was significantly affected by knee flexion angle and anterior tibial load in a fashion remarkably similar to that seen in the anterior cruciate ligament. The magnitude of the in situ force in the anteromedial bundle, in contrast, remained relatively constant, not changing with flexion angle. Significant differences in the direction of the in situ force between the anteromedial bundle and the posterolateral bundle were found only at flexion angles of 0 and 60 degrees and only under applied anterior tibial loads greater than 66 N. We have demonstrated the nonuniformity of the anterior cruciate ligament under unconstrained anterior tibial loads. Our data further suggest that in order for the anterior cruciate ligament replacement graft to reproduce the in situ forces of the normal anterior cruciate ligament, reconstruction techniques should take into account the role of the posterolateral bundle in addition to that of the anteromedial bundle.
前交叉韧带具有复杂的纤维解剖结构，并非被视为均匀结构。目前的前交叉韧带重建术成功地稳定了膝关节，但既未完全恢复正常的膝关节运动学，也未重现正常的韧带功能。为改善重建效果，可能有必要在替代移植物中重现完整前交叉韧带的复杂功能。我们研究了9条人体前交叉韧带的原位力，以及在膝关节屈曲角度为0至90度、施加的胫骨前负荷范围为22至110牛顿时，韧带前后内侧束之间的力分布情况。分析是使用机器人操纵器结合通用力-力矩传感器进行的。在未向韧带附着任何装置的情况下测定原位力，同时允许膝关节在施加负荷时自由移动。我们发现，前交叉韧带的原位力范围从膝关节屈曲90度时施加22牛顿胫骨前负荷下的12.8±7.3牛，到屈曲15度时施加110牛顿负荷下的110.6±14.8牛。在膝关节屈曲角度为0至45度时，后外侧束的原位力大小大于前内侧束，在膝关节屈曲15度、胫骨前负荷为110牛顿时达到最大值75.2±18.3牛。后外侧束的原位力大小受膝关节屈曲角度和胫骨前负荷的显著影响，其方式与在前交叉韧带中观察到的极为相似。相比之下，前内侧束的原位力大小保持相对恒定，不随屈曲角度变化。仅在屈曲角度为0和60度且仅在施加的胫骨前负荷大于66牛顿时，才发现前内侧束和后外侧束的原位力方向存在显著差异。我们已经证明了在无约束的胫骨前负荷下前交叉韧带的不均匀性。我们的数据进一步表明，为使前交叉韧带替代移植物重现正常前交叉韧带的原位力，重建技术除了应考虑前内侧束的作用外，还应考虑后外侧束的作用。
