Höher J, Harner C D, Vogrin T M, Baek G H, Carlin G J, Woo S L
Musculoskeletal Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pennsylvania 15213, USA.
J Orthop Res. 1998 Nov;16(6):675-81. doi: 10.1002/jor.1100160608.
The posterolateral structures of the knee consist of a complex anatomical architecture that includes several components with both static and dynamic functions. Injuries of the posterolateral structures occur frequently in conjunction with ruptures of the posterior cruciate ligament. To investigate the role of the posterolateral structures in maintaining posterior knee stability, we measured the in situ forces in the posterolateral structures and the distribution of force within the structures' major components, i.e., the popliteus complex and the lateral collateral ligament, in response to a posterior tibial load. Eight cadaveric knees were tested. With use of a robotic/universal force-moment sensor testing system, a posterior tibial load of 110 N was applied to the knee, and the resulting five-degree-of-freedom kinematics were measured at flexion angles of 0, 30, 60, 75, and 90 degrees. The knees were tested first in the intact state and then after the posterior cruciate ligament had been resected. These tests were also performed with an additional load of 44 N applied at the aponeurosis to simulate contraction of the popliteus muscle. In the intact knee, the in situ forces in the posterolateral structures were found to decrease with increasing knee flexion. After the posterior cruciate ligament was sectioned, these forces increased significantly at all angles of flexion. With no load applied to the popliteus muscle, the in situ forces in the popliteus complex were similar to those in the lateral collateral ligament. However, with a load of 44 N applied to the popliteus muscle, in situ forces in the popliteus complex were three to five times higher than those in the lateral collateral ligament. These results reveal that in response to posterior tibial loads, the posterolateral structures play an important role at full extension in intact knees and at all angles of flexion in posterior cruciate ligament-deficient knees. The popliteus muscle appears to be a major stabilizer under this loading condition; thus, the inability to restore its function may be a cause of unsatisfactory results in reconstructive procedures of the posterolateral structures of the knee.
膝关节后外侧结构由复杂的解剖结构组成，包括几个具有静态和动态功能的组成部分。后外侧结构损伤常与后交叉韧带断裂同时发生。为了研究后外侧结构在维持膝关节后方稳定性中的作用，我们测量了后外侧结构的原位力以及在胫骨后向负荷作用下该结构主要组成部分（即腘肌复合体和外侧副韧带）内的力分布。对8具尸体膝关节进行了测试。使用机器人/通用力-力矩传感器测试系统，对膝关节施加110 N的胫骨后向负荷，并在0°、30°、60°、75°和90°的屈曲角度下测量由此产生的五自由度运动学数据。膝关节首先在完整状态下进行测试，然后在后交叉韧带切除后进行测试。这些测试还在腱膜处施加44 N的额外负荷以模拟腘肌收缩的情况下进行。在完整膝关节中，发现后外侧结构的原位力随膝关节屈曲增加而减小。后交叉韧带切断后，这些力在所有屈曲角度均显著增加。在未对腘肌施加负荷时，腘肌复合体的原位力与外侧副韧带的相似。然而，在对腘肌施加44 N负荷时，腘肌复合体的原位力比外侧副韧带高3至5倍。这些结果表明，在胫骨后向负荷作用下，后外侧结构在完整膝关节的完全伸展时以及在后交叉韧带损伤膝关节的所有屈曲角度均发挥重要作用。在这种负荷条件下，腘肌似乎是主要的稳定器；因此，无法恢复其功能可能是膝关节后外侧结构重建手术效果不理想的一个原因。
