function of ACL anterior cruciate ligament in a weight bearing limb

 Hello blog readers,

welcome back

I would like to share a new concept hitherto not well taught,  with reference to function of  Anterior cruciate ligament

Google " function of ACL", most if not all articles talk about preventing anterior translation of tibia on the femur. Bing it, again talks about the same concept.  Try even Copilot and ask on this, talks about the same, and some articles will add preventing internal tibial rotation.

Try Pubmed, Very few articles if you search well, will talk about the ACL function on a fixed tibia as we are on weight bearing. This is preventing posterior translation of femur on the tibia, preventing posterior rolling of femoral condyle on the tibial plateau.

Even biomechanics studies do not talk about the femoral translation and rotation on a weight bearing limb.

I would like us to understand that more precisely, ACL prevents posterior translation of lateral femoral condyle on the lateral tibial plateau, thus preventing external rotation of femur on the fixed tibia.

Hope this is of help to understand what we are really trying to achieve by reconstructing ACL

references samples

1. Anterior cruciate ligament

Author: Edwin Ocran, MBChB, MSc • Reviewer: Dimitrios Mytilinaios, MD, PhD Last reviewed: October 30, 2023

Reading time: 2 minutes

2.  Sports Biomech. Author manuscript; available in PMC 2024 Jan 1.

Published in final edited form as:

Sports Biomech. 2023 Jan; 22(1): 1–29. 

Published online 2021 May 7. 

LOADING MECHANISMS OF THE ANTERIOR CRUCIATE LIGAMENT

Mélanie L. Beaulieu, PhD,1 James A. Ashton-Miller, PhD,2,3 and  Edward M. Wojtys, MD1

Am J Sports Med. 2023 Apr; 51(5): 1136–1145. 

Published online 2023 Mar 14. 

3.  Role of the Anterior Cruciate Ligament, Anterolateral Complex, and Lateral Meniscus Posterior Root in Anterolateral Rotatory Knee Instability: A Biomechanical Study

Lukas Willinger, MD,* Kiron K. Athwal, PhD,† Sander Holthof, MEng,† Andreas B. Imhoff, MD,* Andy Williams, MB BS, FRCS(Orth), FFSEM(UK),‡ and  Andrew A. Amis, BSc, PhD, DSc(Eng), FREng†§