On the Estimate of the Two Dominant Axes of the Knee Using an Instrumented Spatial Linkage

2012 ◽  
Vol 28 (2) ◽  
pp. 200-209 ◽  
Author(s):  
Gianluca Gatti
Keyword(s):  
Rotation Axis ◽  
Knee Kinematics ◽  
Simulated Data ◽  
Knee Dislocation ◽  
Degree Of Freedom ◽  
External Fixators ◽  
Human Knee ◽  
Mechanical Joint ◽  
Flexion Extension ◽  
Extension Axis

This article presents the validation of a technique to assess the appropriateness of a 2 degree-of-freedom model for the human knee, and, in which case, the dominant axes of flexion/extension and internal/external longitudinal rotation are estimated. The technique relies on the use of an instrumented spatial linkage for the accurate detection of passive knee kinematics, and it is based on the assumption that points on the longitudinal rotation axis describe nearly circular and planar trajectories, whereas the flexion/extension axis is perpendicular to those trajectories through their centers of rotation. By manually enforcing a tibia rotation while bending the knee in flexion, a standard optimization algorithm is used to estimate the approximate axis of longitudinal rotation, and the axis of flexion is estimated consequently. The proposed technique is validated through simulated data and experimentally applied on a 2 degree-of-freedom mechanical joint. A procedure is proposed to verify the fixed axes assumption for the knee model. The suggested methodology could be possibly valuable in understanding knee kinematics, and in particular for the design and implant of customized hinged external fixators, which have shown to be effective in knee dislocation treatment and rehabilitation.

A New Load Application System for In Vitro Study of Ligamentous Injuries to the Human Knee Joint

1995 ◽  
Vol 117 (4) ◽  
pp. 373-382 ◽  
Author(s):  
J. M. Bach ◽  
M. L. Hull
Keyword(s):  
Knee Joint ◽  
Degree Of Freedom ◽  
Load Application ◽  
Accuracy Evaluation ◽  
Application System ◽  
Human Knee ◽  
Human Knee Joint ◽  
Flexion Extension ◽  
External Loads

This paper describes the design and accuracy evaluation of a new six degree of freedom load application system for in vitro testing of the human knee joint. External loads of both polarity in all six degrees of freedom can be applied either individually or in any combination while the knee is permitted to move unconstrained in response to applied loads. The flexion/extension degree of freedom permits the full physiological range of motion. In addition to external loads, forces of the three major muscle groups (quadriceps, hamstrings, gastrocnemius) crossing the joint can be developed. Full automation and rapid convergence of loads to programmed values are achieved through a computer which feeds command signals to servo controller/electro-pneumatic servo valves. The servo valves regulate pressure to pneumatic actuators which develop the various loads. Experiments undertaken to quantify the accuracy of both load and displacement measurements reveal that errors particularly in load measurement are effectively controlled through the apparatus design.

Three degree of freedom description of movement of the human chest wall

1986 ◽  
Vol 60 (3) ◽  
pp. 928-934 ◽  
Author(s):  
J. C. Smith ◽  
J. Mead
Keyword(s):  
Chest Wall ◽  
Lung Volume ◽  
Pubic Symphysis ◽  
Degree Of Freedom ◽  
Rib Cage ◽  
Additional Degree ◽  
Wall Movement ◽  
Surface Displacements ◽  
Flexion Extension ◽  
Three Degree Of Freedom

A three degree of freedom description of movement of the human chest wall is presented. In addition to the standard variables representing surface displacements of the rib cage and abdominal wall in transverse planes, the description includes a variable representing axial displacements of the chest wall associated with postural movements of the spine and pelvis. A simple technique was developed for quantifying the axial displacements using a single measurement by magnetometry of changes in the distance between a point on the anterior surface of the rib cage near the xiphisternum and a point on the abdominal surface near the pubic symphysis. It was found that axial displacements produced by either flexion-extension of the spine or rotation of the pelvis in the standing postures can be treated as a single degree of freedom. The chest wall displacements induced over the range of axial displacement examined were as large as those normally accompanying a change in lung volume on the order of 30–50% of the vital capacity. It is concluded, however, that although this additional degree of freedom can cause large chest wall displacements, it probably cannot independently change lung volume. This implies that the system is constrained so that there are only a limited number of independent modes of chest wall movement that are capable of producing significant changes in lung volume. It also suggests that the system is constructed so that lung volume can be relatively independent of certain postural distortions of the chest wall.

scholarly journals Design and Characterization of a Novel Knee Articulation Mechanism

2016 ◽  
Vol 21 (3) ◽  
pp. 611-622 ◽  
Author(s):  
M. Olinski ◽  
A. Gronowicz ◽  
A. Handke ◽  
M. Ceccarelli
Keyword(s):  
Sagittal Plane ◽  
Preliminary Design ◽  
Human Knee ◽  
Knee Rehabilitation ◽  
Flexion Extension ◽  
Adjustable Mechanism ◽  
Centre Of Rotation ◽  
Three Degree Of Freedom ◽  
Supporting Device

Abstract The paper is focused on designing a novel controllable and adjustable mechanism for reproducing human knee joint’s complex motion by taking into account the flexion/extension movement in the sagittal plane, in combination with roll and slide. Main requirements for a knee rehabilitation supporting device are specified by researching the knee’s anatomy and already existing mechanisms. A three degree of freedom (3 DOF) system (four-bar like linkage with controlled variable lengths of rockers) is synthesised to perform the reference path of instantaneous centre of rotation (ICR). Finally, a preliminary design of the adaptive mechanism is elaborated and a numerical model is built in Adams. Numerical results are derived from simulations that are presented to evaluate the accuracy of the reproduced movement and the mechanism’s capabilities.

Finite Element Model of the Human Knee Joint to Study Tibio-Femoral Contact Mechanics

2000 ◽  
Author(s):  
Tammy Haut Donahue ◽  
Maury L. Hull ◽  
Mark M. Rashid ◽  
Christopher R. Jacobs
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Degrees Of Freedom ◽  
Soft Tissues ◽  
Element Model ◽  
Human Knee ◽  
Human Knee Joint ◽  
Solid Models ◽  
Flexion Extension ◽  
A New Technique

Abstract A finite element model of the tibio-femoral joint in the human knee was created using a new technique for developing accurate solid models of soft tissues (i.e. cartilage and menisci). The model was used to demonstrate that constraining rotational degrees of freedom other than flexion/extension when the joint is loaded in compression markedly affects the load distribution between the medial and lateral sides of the joint. The model also was used to validate the assumption that the bones can be treated as rigid.

Determining the optimal flexion–extension axis of the elbow in vivo — a study of interobserver and intraobserver reliability

2000 ◽  
Vol 33 (9) ◽  
pp. 1139-1145 ◽  
Author(s):  
M Stokdijk ◽  
M Biegstraaten ◽  
W Ormel ◽  
Y.A de Boer ◽  
H.E.J Veeger ◽  
...  
Keyword(s):  
Intraobserver Reliability ◽  
Flexion Extension ◽  
Extension Axis

The Functional Flexion-Extension Axis of the Knee Corresponds to the Surgical Epicondylar Axis

2005 ◽  
Vol 20 (8) ◽  
pp. 1060-1067 ◽  
Author(s):  
Taiyo Asano ◽  
Masao Akagi ◽  
Takashi Nakamura
Keyword(s):  
Epicondylar Axis ◽  
Flexion Extension ◽  
Extension Axis

Comparison of Strain-Gage and Fiber-Optic Goniometry for Measuring Knee Kinematics During Activities of Daily Living and Exercise

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Abeer A. Mohamed ◽  
Jennifer Baba ◽  
James Beyea ◽  
John Landry ◽  
Andrew Sexton ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Daily Living ◽  
Motion Tracking ◽  
Tracking System ◽  
Knee Kinematics ◽  
Sensor Technology ◽  
Indirect Measures ◽  
Flexion Extension ◽  
Motion Tracking System ◽  
Chair Rise

There is increasing interest in wearable sensor technology as a tool for rehabilitation applications in community or home environments. Recent studies have focused on evaluating inertial based sensing (accelerometers, gyroscopes, etc.) that provide only indirect measures of joint motion. Measurement of joint kinematics using flexible goniometry is more direct, and still popular in laboratory environments, but has received little attention as a potential tool for wearable systems. The aim of this study was to compare two goniometric devices: a traditional strain-gauge flexible goniometer, and a fiberoptic flexible goniometer, for measuring dynamic knee flexion/extension angles during activity of daily living: chair rise, and gait; and exercise: deep knee bends, against joint angles computed from a “gold standard” Vicon motion tracking system. Six young adults were recruited to perform the above activities in the lab while wearing a goniometer on each knee, and reflective markers for motion tracking. Kinematic data were collected simultaneously from the goniometers (one on each leg) and the motion tracking system (both legs). The results indicate that both goniometers were within 2–5 degrees of the Vicon angles for gait and chair rise. For some deep knee bend trials, disagreement with Vicon angles exceeded ten degrees for both devices. We conclude that both goniometers can record ADL knee movement faithfully and accurately, but should be carefully considered when high (>120 deg) knee flexion angles are required.

Three-Dimensional Dynamic Simulation of Total Knee Replacement Motion During a Step-Up Task

2001 ◽  
Vol 123 (6) ◽  
pp. 599-606 ◽  
Author(s):  
Stephen J. Piazza ◽  
Scott L. Delp
Keyword(s):  
Activity Patterns ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Knee Kinematics ◽  
Prosthetic Knee ◽  
Total Knee Replacements ◽  
Contact Points ◽  
Flexion Extension ◽  
Knee Replacements ◽  
Total Knee

A three-dimensional, dynamic model of the tibiofemoral and patellofemoral articulations was developed to predict the motions of knee implants during a step-up activity. Patterns of muscle activity, initial joint angles and velocities, and kinematics of the hip and ankle were measured experimentally and used as inputs to the simulation. Prosthetic knee kinematics were determined by integration of dynamic equations of motion subject to forces generated by muscles, ligaments, and contact at both the tibiofemoral and patellofemoral articulations. The modeling of contacts between implants did not rely upon explicit constraint equations; thus, changes in the number of contact points were allowed without modification to the model formulation. The simulation reproduced experimentally measured flexion–extension angle of the knee (within one standard deviation), but translations at the tibiofemoral articulations were larger during the simulated step-up task than those reported for patients with total knee replacements.

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