Predicting the Effect of Localized ACL Damage on Neighbor Ligament Mechanics via Finite Element Modeling.

Alexander Knapp,Lakiesha N Williams

doi:10.3390/bioengineering9020054

Abstract

The anterior cruciate ligament (ACL) plays a pivotal role in support of the knee under loading. When damaged, it is known that substantial changes in the mechanics of the neighboring ligaments can be observed. However, a localized damage approach to investigating how ACL deficiency influences the neighboring ligaments has not been carried out. To do this, a finite element model, incorporating a continuum damage material model of the ACL, was implemented. Localized ACL damage was induced using high quadriceps force loading. Once damaged, anterior shear forces or tibial torque loadings were applied to the knee joint. The relative changes in stress contour and average mid-substance stress were examined for each of the neighboring ligaments following localized ACL damage. It was observed that localized ACL damage could produce notable changes in the mechanics of the neighboring knee ligaments, with non-homogenous stress contour shape changes and average stress magnitude being observed to increase in most cases, with a notable exception occurring in the MCL for both loading modes. In addition, the ligament bearing the most loading also changed with ACL deficiency. These changes carry implications as to morphological effects that may be induced following localized ACL damage, indicating that early diagnosis of ACL injury may be helpful in mitigating other complications post injury.

Highlights

The anterior cruciate ligament (ACL) is a major structural component of the knee, being primarily responsible for inhibiting anterior tibial translation and playing a role in supporting the knee during valgus, varus, and torque moments [1–4]
It was observed that localized ACL damage could produce notable changes in the mechanics of the neighboring knee ligaments, with non-homogenous stress contour shape changes and average stress magnitude being observed to increase in most cases, with a notable exception occurring in the MCL for both loading modes
Moderate injuries caused by the 2000 N quadriceps force can induce subtle shifts in the contour, and complete destruction of the ACL yields drastically different stress contours

Summary

Introduction

The anterior cruciate ligament (ACL) is a major structural component of the knee, being primarily responsible for inhibiting anterior tibial translation and playing a role in supporting the knee during valgus, varus, and torque moments [1–4]. Patients report high pain values and noticeable increases in joint instability, with potentially high medical costs for treatments such as surgical intervention [5,6]. Long-term lifestyle changes can occur, which can be detrimental to athletic careers, leading to long-term or even lifelong removal from play [7–9]. Due to the prevalence and potential severity of complications following injury, it is paramount to increase our understanding of the mechanisms of ACL injury and resulting joint kinematic changes. With increased knowledge of the mechanics of ACL injury, clinicians and athletic trainers can devise new methods to prevent ACL injury

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