Nawabi Danyal H, Tucker Scott, Schafer Kevin A, Zuiderbaan Hendrik Aernout, Nguyen Joseph T, Wickiewicz Thomas L, Imhauser Carl W, Pearle Andrew D
Sports Medicine and Shoulder Service, Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York, USA
Department of Biomechanics, Hospital for Special Surgery, New York, New York, USA.
Am J Sports Med. 2016 Oct;44(10):2563-2571. doi: 10.1177/0363546516652876. Epub 2016 Jul 20.
The femoral insertion of the anterior cruciate ligament (ACL) has direct and indirect fiber types located within the respective high (anterior) and low (posterior) regions of the femoral footprint.
The fibers in the high region of the ACL footprint carry more force and are more isometric than the fibers in the low region of the ACL footprint.
Controlled laboratory study.
Ten fresh-frozen cadaveric knees were mounted to a robotic manipulator. A 134-N anterior force at 30° and 90° of flexion and combined valgus (8 N·m) and internal (4 N·m) rotation torques at 15° of flexion were applied simulating tests of anterior and rotatory stability. The ACL was sectioned at the femoral footprint by detaching either the higher band of fibers neighboring the lateral intercondylar ridge in the region of the direct insertion or the posterior, crescent-shaped fibers in the region of the indirect insertion, followed by the remainder of the ACL. The kinematics of the ACL-intact knee was replayed, and the reduction in force due to each sectioned portion of insertion fibers was measured. Isometry was assessed at anteromedial, center, and posterolateral locations within the high and low regions of the femoral footprint.
With an anterior tibial force at 30° of flexion, the high fibers carried 83.9% of the total anterior ACL load compared with 16.1% in the low fibers (P < .001). The high fibers also carried more anterior force than the low fibers at 90° of flexion (95.2% vs 4.8%; P < .001). Under combined torques at 15° of flexion, the high fibers carried 84.2% of the anterior ACL force compared with 15.8% in the low fibers (P < .001). Virtual ACL fibers placed at the anteromedial portion of the high region of the femoral footprint were the most isometric, with a maximum length change of 3.9 ± 1.5 mm.
ACL fibers located high within the femoral footprint bear more force during stability testing and are more isometric during flexion than low fibers.
It may be advantageous to create a "higher" femoral tunnel during ACL reconstruction at the lateral intercondylar ridge.
前交叉韧带（ACL）在股骨的附着点有直接纤维类型和间接纤维类型，分别位于股骨足迹的高（前方）、低（后方）区域。
ACL足迹高区域的纤维比低区域的纤维承受更大的力且更等长。
对照实验室研究。
将10个新鲜冷冻的尸体膝关节安装到机器人操纵器上。在屈膝30°和90°时施加134 N的前向力，在屈膝15°时施加联合外翻（8 N·m）和内旋（4 N·m）扭矩，模拟前向和旋转稳定性测试。在股骨足迹处切断ACL，通过分离直接附着区域中靠近外侧髁间嵴的较高纤维束或间接附着区域中的后新月形纤维，然后切断ACL的其余部分。重现完整ACL膝关节的运动学，测量由于每部分切断的附着纤维导致的力的减小。在股骨足迹的高、低区域内的前内侧、中心和后外侧位置评估等长性。
在屈膝30°时施加胫骨前向力，高区域纤维承受ACL前向总负荷的83.9%，而低区域纤维为16.1%（P <.001）。在屈膝90°时，高区域纤维也比低区域纤维承受更多的前向力（95.2%对4.8%；P <.001）。在屈膝15°的联合扭矩下，高区域纤维承受ACL前向力的84.2%，而低区域纤维为15.8%（P <.001）。放置在股骨足迹高区域前内侧部分的虚拟ACL纤维最等长，最大长度变化为3.9±1.5 mm。
在稳定性测试期间，位于股骨足迹高处的ACL纤维比低处纤维承受更大的力，并且在屈膝过程中更等长。
在ACL重建过程中，在外侧髁间嵴处创建一个“更高”的股骨隧道可能是有利的。
