ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

BIOMECHANICAL ANALYSIS OF THE MUSCULAR AND LIGAMENT
BEHAVIOR OF THE KNEE JOINT THROUGH A SUBJECT-SPECIFIC
COMPUTATIONAL MODEL
ABSTRACT
S. Bersini 1,2 , V. Sansone 3 , F. Anasetti 4 , F. Galbusera 4 , C.A. Frigo 5
The interaction and load sharing between muscles, ligaments and articulating surfaces is
crucial for the stability of the knee. The aim of the present work is to develop an
effective multibody dynamics-based model that allows a quick subject-specific
assessment of ligaments, muscular behavior and contact forces.
This paper shows the results of ‘quasi-static’ simulations of a squat movement between
0° and 90° of flexion in gravitational force field. During this movement the lengths of
anterior cruciate ligament (ACL) and lateral collateral ligament (LCL) decreased up to
21% and 10.5%, respectively, while the lengths of medial collateral ligament (MCL)
and posterior cruciate ligament (PCL) increased. Quadriceps muscle force at
equilibrium increased during flexion reaching a value of 3.88 body weight (BW) at 90°
of flexion. Tibio-femoral contact forces changed non-linearly with joint angle and
achieved a maximum value of 4.58 BW at 90° of flexion.
Once completely developed this model could be used to investigate the effect of several
key factors in the surgical planning that could affect the knee biomechanics and the
results of the intervention.
1. INTRODUCTION
The load sharing between muscles, ligaments and bone’s articulating surfaces represents
a critical point for the stability of the knee joint and has yet to be completely understood
[1].
To date several mathematical and numerical models have been developed to study knee
kinematics and dynamics under prescribed conditions of loading and constraints.
Computational simulations have been carried out to analyze how implant malpositioning
or deformity affect the patient's total knee arthroplasty output in terms of
contact forces [2], while analytical studies have been performed to quantify ligament
loading and tibio-femoral or patello-femoral forces during activities of daily living [1,
3-5].
In this work we present a multibody dynamics-based musculoskeletal model aimed at
analyzing ligaments and contact forces between bony structures in a physiological knee
1
Laboratory of Biological Structure Mechanics, Gruppo Ospedaliero San Donato Foundation, Milano,
Italy
2
Department of Bioengineering, Politecnico di Milano, Milano, Italy
3
Dipartimento di Ortopedia e Traumatologia, Università degli Studi di Milano, Milano, Italy
4
Laboratory of Biological Structure Mechanics, IRCCS Istituto Ortopedico Galeazzi, Milano, Italy
5
Biomechanics and Motor Control Laboratory, TBM Lab, Department of Bioengineering, Politecnico di
Milano, Milano, Italy