In-situ mechanical behavior and slackness of the anterior cruciate ligament at multiple knee flexion angles

H H Rachmat; D Janssen; G J Verkerke; R L Diercks; N Verdonschot

doi:10.1016/j.medengphy.2015.11.011

In-situ mechanical behavior and slackness of the anterior cruciate ligament at multiple knee flexion angles

Med Eng Phys. 2016 Mar;38(3):209-15. doi: 10.1016/j.medengphy.2015.11.011. Epub 2015 Dec 22.

Authors

H H Rachmat¹, D Janssen², G J Verkerke³, R L Diercks⁴, N Verdonschot⁵

Affiliations

¹ Department of Biomedical Engineering, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands; Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Department of Electrical Engineering, Institut Teknologi Nasional (ITENAS) Bandung, West Java, Indonesia.
² Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: Dennis.Janssen@radboudumc.nl.
³ Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands; Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
⁴ Orthopaedics University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands.
⁵ Orthopaedic Research Laboratory, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands; Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands.

PMID: 26726797
DOI: 10.1016/j.medengphy.2015.11.011

Abstract

In this study the in-situ tensile behavior and slackness of the anterior cruciate ligament (ACL) was evaluated at various knee flexion angles. In four cadaveric knees the ACL was released at the tibial insertion, after which it was re-connected to a tensiometer. After pre-tensioning (10 N) the ACL in full-extension, the knee was flexed from 0° to 150° at 15° increments, during which the ACL tension was measured. At each angle the ACL was subsequently elongated and shortened under displacement control, while measuring the ACL tension. In this manner, the pre-tension or the slackness, and the mechanical response of the ACL were measured. All ACL's displayed a higher tension at low (0°-60°) and high (120°-150°) flexion angles. The ACL slackness depended on flexion angle, with the highest slackness found at 75°-90°. Additionally, the ACL stiffness also varied with flexion angle, with the ACL behaving stiffer at low and high flexion angels. In general, the ACL was stiffest at 150°, and most compliant at 90°. The results of this study contribute to understanding the mechanical behavior of the ACL in-situ, and may help tuning and validating computational knee models studying ACL function.

Keywords: ACL; Displacement; In-situ; Knee flexion; Slackness; Tension.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Aged, 80 and over
Anterior Cruciate Ligament / physiology*
Biomechanical Phenomena
Female
Humans
Knee / physiology*
Male
Materials Testing*
Mechanical Phenomena*
Movement*
Tensile Strength