Sports Medicine Institute, Hospital for Special Surgery, New York, New York, USA.
Department of Biomechanics, Hospital for Special Surgery, New York, New York, USA.
Am J Sports Med. 2020 Nov;48(13):3183-3193. doi: 10.1177/0363546520959322. Epub 2020 Oct 5.
The biomechanical effect of lateral extra-articular tenodesis (LET) performed in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) on load sharing between the ACL graft and the LET and on knee kinematics is not clear.
PURPOSE/HYPOTHESIS: The purpose was to quantify the effect of LET on (1) forces carried by both the ACL graft and the LET and (2) tibiofemoral kinematics in response to simulated pivot shift and anterior laxity tests. We hypothesized that LET would decrease forces carried by the ACL graft and anterior tibial translation (ATT) in response to simulated pivoting maneuvers and during simulated tests of anterior laxity.
Controlled laboratory study.
Seven cadaveric knees (mean age, 39 ± 12 years [range, 28-54 years]; 4 male) were mounted to a robotic manipulator. The robot simulated clinical pivoting maneuvers and tests of anterior laxity: namely, the Lachman and anterior drawer tests. Each knee was assessed in the following states: ACL intact, ACL sectioned, ACL reconstructed (using a bone-patellar tendon-bone autograft), and after performing LET (the modified Lemaire technique after sectioning of the anterolateral ligament and Kaplan fibers). Resultant forces carried by the ACL graft and LET at the peak applied loads were determined via superposition. ATT was determined in response to the applied loads.
With the applied pivoting loads, performing LET decreased ACL graft force up to 80% (44 ± 12 N; < .001) and decreased ATT of the lateral compartment compared with that of the intact knee up to 7.6 ± 2.9 mm ( < .001). The LET carried up to 91% of the force generated in the ACL graft during isolated ACLR (without LET). For simulated tests of anterior laxity, performing LET decreased ACL graft force by 70% (40 ± 20 N; = .001) for the anterior drawer test with no significant difference detected for the Lachman test. No differences in ATT were deteced between ACLR with LET and the intact knee on both the Lachman and the anterior drawer tests ( = .409). LET reduced ATT compared with isolated ACLR on the simulated anterior drawer test by 2.4 ± 1.8 mm ( = .032) but not on the simulated Lachman test.
In a cadaveric model, LET in combination with ACLR transferred loads from the ACL graft to the LET and reduced ATT with applied pivoting loads and during the simulated anterior drawer test. The effect of LET on ACL graft force and ATT was less pronounced on the simulated Lachman test.
LET in addition to ACLR may be a suitable option to offload the ACL graft and to reduce ATT in the lateral compartment to magnitudes less than that of the intact knee with clinical pivoting maneuvers. In contrast, LET did not offload the ACL graft or add to the anterior restraint provided by the ACL graft during the Lachman test.
在进行前交叉韧带（ACL）重建（ACLR）时进行外侧关节外腱固定（LET）的生物力学效果，即在模拟枢轴转移和前侧松弛测试中，ACL 移植物和 LET 之间的载荷分担以及膝关节运动学方面尚不清楚。
目的/假设：目的是定量研究 LET 对以下方面的影响：（1）ACL 移植物和 LET 承受的力；（2）胫骨股骨运动学。我们假设 LET 会降低 ACL 移植物在前侧旋转运动和前侧松弛模拟测试中的力和前胫骨平移（ATT）。
对照实验室研究。
7 个尸体膝关节（平均年龄，39 ± 12 岁[范围，28-54 岁]；4 名男性）安装在机器人操纵器上。机器人模拟了临床枢轴转移运动和前侧松弛测试：即拉赫曼（Lachman）和前抽屉测试。在以下状态下评估每个膝关节：ACL 完整，ACL 切断，ACL 重建（使用骨-髌腱-骨自体移植物），以及进行 LET 后（切断前外侧韧带和卡普兰纤维后进行改良的勒梅尔技术）。通过叠加确定在施加的峰值负载下 ACL 移植物和 LET 承受的力。响应施加的负载确定 ATT。
在施加的枢轴负载下，进行 LET 可使 ACL 移植物的力降低多达 80%（44 ± 12 N；<0.001），并且与完整膝关节相比，外侧间隔的 ATT 降低多达 7.6 ± 2.9 mm（<0.001）。LET 在 ACLR 期间（无 LET）可承载 ACL 移植物产生的力的高达 91%。对于前侧松弛测试，进行 LET 可使 ACL 移植物的力降低 70%（40 ± 20 N；=0.001），而拉赫曼测试无明显差异。在 Lachman 和前抽屉测试中，ACL 带有 LET 和完整膝关节之间的 ATT 无差异（=0.409）。与 ACLR 相比，LET 在模拟的前抽屉测试中降低了 ACL 移植物的 ATT，降低了 2.4 ± 1.8 mm（=0.032），但在模拟的拉赫曼测试中没有降低。
在尸体模型中，LET 联合 ACLR 将载荷从 ACL 移植物转移到 LET，并减少了旋转运动和模拟前抽屉测试中的 ATT。在模拟的拉赫曼测试中，LET 对 ACL 移植物力和 ATT 的影响不如在模拟前抽屉测试中明显。
除 ACLR 外，LET 可能是一种合适的选择，可以减轻 ACL 移植物的负荷，并降低外侧间隔的 ATT，使其低于临床枢轴转移运动中的完整膝关节。相比之下，在拉赫曼测试中，LET 不会减轻 ACL 移植物的负荷或增加 ACL 移植物提供的前侧约束。
