Modeling of the condyle elements within a biomechanical knee model

Abstract

The development of a computational multibody knee model able to capture some of the fundamental properties of the human knee articulation is presented. This desideratum is reached by including the kinetics of the real knee articulation. The research question is whether an accurate modeling of the condyle contact in the knee will lead to reproduction of the complex combination of flexion/extension, abduction/adduction, and tibial rotation observed in the real knee. The model is composed by two anatomic segments, the tibia and the femur, whose characteristics are functions of the geometric and anatomic properties of the real bones. The biomechanical model characterization is developed under the framework of multibody systems methodologies using Cartesian coordinates. The type of approach used in the proposed knee model is the joint surface contact conditions between ellipsoids, representing the two femoral condyles, and points, representing the tibial plateau and the menisci. These elements are closely fitted to the actual knee geometry. This task is undertaken by considering a parameter optimization process to replicate experimental data published in the literature, namely that by Lafortune and his coworkers in 1992. Then kinematic data in the form of flexion/extension patterns are imposed on the model corresponding to the stance phase of the human gait. From the results obtained, by performing several computational simulations, it can be observed that the knee model approximates the average secondary motion patterns observed in the literature. Because the literature reports considerable inter-individual differences in the secondary motion patterns, the knee model presented here is also used to check whether it is possible to reproduce the observed differences with reasonable variations of bone shape parameters. This task is accomplished by a parameter study, in which the main variables that define the geometry of condyles are taken into account. It was observed that the data reveal a difference in secondary kinematics of the knee in flexion versus extension. The likely explanation for this fact is the elastic component of the secondary motions created by the combination of joint forces and soft tissue deformations. The proposed knee model is, therefore, used to investigate whether this observed behavior can be explained by reasonable elastic deformations of the points representing the menisci in the model.

Design and control of an active ankle–knee orthosis inspired by biarticular musculoskeletal structure of the human lower limb

“…With this τ m design, the force at the end-effector is calculated as (35) according to the kinematics in (5) and the inverse statics in (10). thus determine the direction and magnitude of the force to be generated at the end-effector.…”

“…Unlike other design of orthoses of a knee joint which mostly focuses on the precise and practical design of one joint [8][9][10], this paper introduces a biarticular elastic mechanism into an ankle-knee orthosis in order to improve the torque transmission efficiency; a leg system to assist a person with a physical impairment in his/her lower limb is designed with one active actuator at the ankle joint and one passive mechanism that acts as the biarticular elasticity connecting the ankle joint and the knee joint. Fig.…”

Modelling and simulation of alternative designs for the femur–implant interface of Journey patellofemoral prosthesis

“…Frequent stimulation is essential to maintain knee healthiness and functionality, while its complexity makes it highly susceptible to injury of bones, ligaments and muscles. 1–3…”

Influence of the Hip Joint Modeling Approaches on the Kinematics of Human Gait

“…The authors concluded that the musculo-skeletal model with a limited number of degrees-of-freedom and with some angle-dependent joint coupling and stiffness seems to provide satisfactory musculo-tendon forces and joint reaction forces. Nevertheless, with this approach, significant decrease in the kinematic precision compared with the living body could occur because the idealized models fail to capture the more complex aspects of joint kinematics [18]. However, the physical and mechanical properties of the natural and artificial human articulations including the effects of friction, lubrication and intra-contact force joints were neglected.…”