title: A dynamic multibody model of the physiological knee to predict internal loads during movement in gravitational field.
abstract: Obtaining tibio-femoral (TF) contact forces, ligament deformations and loads during daily life motor tasks would be useful to better understand the aetiopathogenesis of knee joint diseases or the effects of ligament reconstruction and knee arthroplasty. However, methods to obtain this information are either too simplified or too computationally demanding to be used for clinical application. A multibody dynamic model of the lower limb reproducing knee joint contact surfaces and ligaments was developed on the basis of magnetic resonance imaging. Several clinically relevant conditions were simulated, including resistance to hyperextension, varus-valgus stability, anterior-posterior drawer, loaded squat movement. Quadriceps force, ligament deformations and loads, and TF contact forces were computed. During anterior drawer test the anterior cruciate ligament (ACL) was maximally loaded when the knee was extended (392 N) while the posterior cruciate ligament (PCL) was much more stressed during posterior drawer when the knee was flexed (319 N). The simulated loaded squat revealed that the anterior fibres of ACL become inactive after 60° of flexion in conjunction with PCL anterior bundle activation, while most components of the collateral ligaments exhibit limited length changes. Maximum quadriceps and TF forces achieved 3.2 and 4.2 body weight, respectively. The possibility to easily manage model parameters and the low computational cost of each simulation represent key points of the present project. The obtained results are consistent with in vivo measurements, suggesting that the model can be used to simulate complex and clinically relevant exercises.
authors.affiliation: a Laboratory of Biological Structure Mechanics, Gruppo Ospedaliero San Donato Foundation , Via Riccardo Galeazzi 4, Milano 20161, Italy.|b Department of Electronics, Information and Bioengineering , Politecnico di Milano , Milano , Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Bersini
authors.affiliation: c Dipartimento di Ortopedia e Traumatologia , Università degli Studi di Milano , Milano , Italy.|d IRCCS Istituto Ortopedico Galeazzi , Via Riccardo Galeazzi 4, Milano 20161 , Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Sansone
authors.affiliation: e Biomechanics and Motor Control Laboratory, TBM Lab, Department of Electronics, Information and Bioengineering , Politecnico di Milano , Via Golgi 39, Milano 20133 , Italy.
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Frigo
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000502:physiology; D019645:Arthroplasty, Replacement, Knee; D015992:Body Mass Index; D003198:Computer Simulation; D005269:Femur; D006112:Gravitation; D006801:Humans; D007717:Knee / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008954:Models, Biological; D009068:Movement; D016119:Posterior Cruciate Ligament / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D015203:Reproducibility of Results
keywords: knee internal loads; knee ligaments; knee model; multibody dynamics