The contribution of the anterior cruciate ligament to knee joint kinematics: Evaluation of its in situ forces using a robot/universal force-moment sensor test system

Autor: Savio L. C. Woo, Ross J. Fox, Kevin A. Hildebrand, Masataka Sakane
Rok vydání: 1996
Předmět:
Zdroj: Journal of Orthopaedic Science. 1:335-347
ISSN: 0949-2658
DOI: 10.1007/bf02348844
Popis: Damage to one of the major soft tissue structures of the knee joint, namely, the anterior cruciate ligament (ACL), can lead to significant changes in joint kinematics, which the patient perceives as instability. In this manuscript, we illustrate the importance of the anatomical complexity and biomechanical function of the ACL in knee joint kinematics. Further, we introduce a new test system whereby the in situ forces of the ACL and multiple-degree of freedom (DOF) knee kinematics are determined. Using a robotic manipulator coupled with a universal force-moment sensor (UFS), these forces can be determined directly and without making mechanical contact with the tissue. We have found that the in situ force in the human ACL in response to 110N of anterior tibial load decreases significantly with knee flexion, changing from 110.6±14.8N at 15° of flexion to 71.1±29.5 N at 90° of flexion. Distribution of the in situ force within the human ACL was determined by consistently defining its distribution in anteromedial (AM) and posterolateral (PL) bundles of the ACL. In situ forces in the PL bundle in response to 110N of anterior tibial load showed a maximum of 75.2±18.3 N at 15°, and were significantly larger than those in the AM bundle. On the contrary, in situ forces in the AM bundle varied from a maximum of 47.4±34.2N at 60° to a minimum of 32.6±13.3N at 0°. In the porcine ACL, the magnitude of in situ force was not significantly affected as the constraints varied from 1-DOF to 5-DOF. However, the directions of the force were significantly different between 1-DOF and 5-DOF conditions. The ACL reconstruction study has shown that anatomical (proximal) ACL graft fixation in the tibial tunnel more closely reproduced the knee kinematics and in situ force of the native ACL than those in central and distal fixations. These findings have important implications in terms of the mechanisms of ACL injuries, complexity of the ACL function, and anatomy-and biomechanics-based approaches to ACL reconstruction.
Databáze: OpenAIRE
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