A Model of Human Knee Ligaments in the Sagittal Plane: Part 2: Fibre Recruitment under Load

1992 ◽  
Vol 206 (3) ◽  
pp. 135-145 ◽  
Author(s):  
A B Zavatsky ◽  
J J O'Connor
Keyword(s):  
Sagittal Plane ◽  
Geometric Analysis ◽  
Collateral Ligaments ◽  
Compatibility Conditions ◽  
Knee Ligaments ◽  
Human Knee ◽  
Flexion Extension ◽  
Passive Flexion ◽  
Tibial Translation ◽  
Anterior Posterior

A mathematical model of the knee ligaments in the sagittal plane is used to study the forces in the cruciate and collateral ligaments produced by anterior/posterior tibial translation. The model is based on ligament fibre functional architecture. Geometric analysis of the deformed configurations of the model ligaments provides the additional compatibility conditions necessary for calculation of the statically indeterminate distributions of strain and stress within the ligaments and the sharing of load between ligaments. The investigation quantifies the process of ligament fibre recruitment, which occurs when fibres made slack by passive flexion/extension of the knee stretch and change their spatial positions in order to resist applied loads. The calculated ligament forces are in reasonable agreement with experimental results reported in the literature. The model explains some subtleties of ligament function not incorporated in models that represent the ligaments by a small number of lines.

A Model of Human Knee Ligaments in the Sagittal Plane: Part 1: Response to Passive Flexion

1992 ◽  
Vol 206 (3) ◽  
pp. 125-134 ◽  
Author(s):  
A B Zavatsky ◽  
J J O'Connor
Keyword(s):  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Fibre Length ◽  
Natural Fibre ◽  
Knee Ligaments ◽  
Human Knee ◽  
Flexion Extension ◽  
Fibre Strain ◽  
Passive Flexion ◽  
Length Changes

The development of a mathematical model of the knee ligaments in the sagittal plane is presented. Essential features of the model are (a) the representation of selected cruciate ligament fibres as isometric links in a kinematic mechanism that controls passive knee flexion and (b) the mapping of all other ligament fibres between attachments on the tibia and femur. Fibres slacken and tighten as the ligament attachment areas on the bones move relative to each other. The model is used to study the shape and fibre length changes of the cruciate and collateral ligaments in response to passive flexion/extension of the knee. The model ligament shape and fibre length changes compare well qualitatively with experimental results reported in the literature. The results suggest that when designing and implanting a ligament replacement with the aim of reproducing the natural fibre strain patterns, the surgeon must not only implant through the natural attachment areas but must also maintain the natural fibre mapping and render all fibres just tight at the appropriate flexion angle.

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.

Anterior Cruciate Ligament Graft Conditioning Required to Prevent an Abnormal Lachman and Pivot Shift After ACL Reconstruction: A Robotic Study of 3 ACL Graft Constructs

2019 ◽  
Vol 47 (6) ◽  
pp. 1376-1384 ◽  
Author(s):  
Frank R. Noyes ◽  
Lauren E. Huser ◽  
Brad Ashman ◽  
Michael Palmer
Keyword(s):  
Patellar Tendon ◽  
Pivot Shift ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
Acl Graft ◽  
Flexion Extension ◽  
Anterior Tibial ◽  
Tibial Translation ◽  
Bone Patellar Tendon ◽  
Anterior Posterior

Background: Anterior cruciate ligament (ACL) graft conditioning protocols to decrease postoperative increases in anterior tibial translation and pivot-shift instability have not been established. Purpose: To determine what ACL graft conditioning protocols should be performed at surgery to decrease postoperative graft elongation after ACL reconstruction. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic simulator evaluated 3 ACL graft constructs in 7 cadaver knees for a total of 19 graft specimens. Knees were tested before and after ACL sectioning and after ACL graft conditioning protocols before reconstruction. The ACL grafts consisted of a 6-strand semitendinosus-gracilis TightRope, bone–patellar tendon–bone TightRope, and bone–patellar tendon–bone with interference screws. Two graft conditioning protocols were used: (1) graft board tensioning (20 minutes, 80 N) and (2) cyclic conditioning (5°-120° of flexion, 90-N anterior tibial load) after graft reconstruction to determine the number of cycles needed to obtain a steady state with no graft elongation. After conditioning, the grafts were cycled a second time under anterior-posterior loading (100 N, 25° of flexion) and under pivot-shift loading (100 N anterior, 5-N·m internal rotation, 7 N·m valgus) to verify that the ACL flexion-extension conditioning protocol was effective. Results: Graft board tensioning did not produce a steady-state graft. Major increases in anterior tibial translation occurred in the flexion-extension graft-loading protocol at 25° of flexion (mean ± SD: semitendinosus-gracilis TightRope, 3.4 ± 1.1 mm; bone–patellar tendon–bone TightRope, 3.2 ± 1.0 mm; bone–patellar tendon–bone with interference screws, 2.4 ± 1.5 mm). The second method of graft conditioning (40 cycles, 5°-120° of flexion, 90-N anterior load) produced a stable conditioned state for all grafts, as the anterior translations of the anterior-posterior and pivot-shift cycles were statistically equivalent ( P < .05, 1-20 cycles). Conclusion: ACL graft board conditioning protocols are not effective, leading to deleterious ACL graft elongations after reconstruction. A secondary ACL graft conditioning protocol of 40 flexion-extension cycles under 90-N graft loading was required for a well-conditioned graft, preventing further elongation and restoring normal anterior-posterior and pivot-shift translations. Clinical Relevance: There is a combined need for graft board tensioning and robust cyclic ACL graft loading before final graft fixation to restore knee stability.

The Effects of Femoral Fixed Body Coordinate System Definition on Knee Kinematic Description

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nathaniel M. Lenz ◽  
Amitkumar Mane ◽  
Lorin P. Maletsky ◽  
Nicholas A. Morton
Keyword(s):  
Sagittal Plane ◽  
External Rotation ◽  
Frontal Plane ◽  
Helical Axis ◽  
Anatomical Landmarks ◽  
Knee Kinematic ◽  
Coordinate Systems ◽  
Knee Simulator ◽  
Flexion Extension ◽  
Anterior Posterior

Understanding the differences in knee kinematic descriptions is important for comparing data from different laboratories and observing small but important changes within a set of knees. The purpose of this study was to identify how differences in fixed body femoral coordinate systems affect the described tibiofemoral and patellofemoral kinematics for cadaveric knee studies with no hip present. Different methods for describing kinematics were evaluated on a set of seven cadaveric knees during walking in a dynamic knee simulator. Three anatomical landmark coordinate systems, a partial helical axis, and an experimental setup-based system were examined. The results showed that flexion-extension was insensitive to differences in the kinematic systems tested, internal-external rotation was similar for most femoral coordinate systems although there were changes in absolute position, varus-valgus was the most sensitive to variations in flexion axis direction, and anterior-posterior motion was most sensitive to femoral origin location. Femoral coordinate systems that define the sagittal plane using anatomical landmarks and locate the flexion axis perpendicular to the femur’s mechanical axis in the frontal plane were typically similar and described kinematics most consistently.

Human Knee Inverse Dynamics Model of Vertical Jump Exercise

2019 ◽  
Vol 14 (10) ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Ricardo Moreno
Keyword(s):  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Vertical Jump ◽  
Contact Forces ◽  
Collateral Ligaments ◽  
Dynamics Model ◽  
Human Knee ◽  
Jump Exercise ◽  
Joint Forces ◽  
Patella Ligament

Abstract This work deals with the dynamics of the human knee during vertical jump exercise. The focus is on the joint forces necessary to produce the jump and to dissipate energy during landing. A two-dimensional (2D) sagittal plane, inverse dynamics human leg model is developed. This model uses data from a motion capture system and force plates in order to predict knee and hip joint forces during the vertical jump exercise. The model consists of three bony structures femur, tibia, and patella, ligament structures to include both cruciate and collateral ligaments, and knee joint muscles. The inverse dynamics model is solved using optimization in order to predict joint forces during this exercise. matlab software package is used for the optimization computations. Results are compared with data available in the literature. This work provides insight regarding contact forces and ligaments forces, muscle forces, and knee and hip contact forces in the vertical jump exercise.

Traction load, tong position, and head support significantly influence cervical spine loading during traction

2019 ◽  
Vol 234 (1) ◽  
pp. 110-117
Author(s):  
Joshua M Hammond ◽  
Belal Tarakji ◽  
Charles Frank ◽  
Tyler Stewart ◽  
David Fernandez ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Shear Force ◽  
Sagittal Plane ◽  
Mechanical Effect ◽  
Neutral Position ◽  
Flexion Extension ◽  
Flexion Moment ◽  
Cervical Traction ◽  
Traction Load ◽  
Anterior Posterior

Some cervical dislocation injuries may be acutely treated with traction via Gardner-Wells tongs, which are attached to the skull via two pins. While a variety of techniques have been proposed and utilized in the literature and clinical practice to use the tongs, these techniques have not been methodically studied to confirm how they transmit loads to the cervical spine. The current study investigated the mechanical effect of different traction techniques in a laboratory setting. A 50th male Hybrid anthropomorphic test device was used as a human surrogate to represent an average male in height and weight was modified to represent a patient with a unilateral facet dislocation injury. Electronic sensors at the atlanto-occipital joint recorded the loading delivered to the superior cervical spine by traction loading. Combinations of the following variables were evaluated as traction loads were progressively increased to one-third of body weight: tong pin position in the skull (anterior–posterior and superior–inferior to the recommended neutral position), traction cable angle in the sagittal plane (elevated, horizontal, declined), and presence or absence of an occipital support. Analysis of the cervical axial traction loads showed that the only significant predictor of cervical tension was the magnitude of the traction load. Anterior–posterior changes in the pin positions in the skull significantly influenced the cervical flexion–extension moment and anterior-posterior (AP) shear. The data show that a combined cervical tension, flexion moment, and anterior shear force can be achieved with posteriorly biased pins and a bolster behind the head. Increasing the angle of traction cable increased the cervical flexion moment and anterior shear force. The following variables should be carefully considered when applying cervical traction since they significantly affect cervical loading: magnitude of the hanging traction load, anterior–posterior pin position, use of an occipital bolster, and traction load angle.

scholarly journals The Effects of External Loads and Muscle Forces on the Knee Joint Ligaments during Walking: A Musculoskeletal Model Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2356
Author(s):  
Carlo Albino Frigo ◽  
Lucia Donno
Keyword(s):  
Knee Joint ◽  
Cruciate Ligament ◽  
Musculoskeletal Model ◽  
Optimization Approach ◽  
Muscle Forces ◽  
Collateral Ligaments ◽  
Flexion Extension ◽  
Lateral Collateral Ligaments ◽  
Gastrocnemius Muscles ◽  
External Loads

A musculoskeletal model was developed to analyze the tensions of the knee joint ligaments during walking and to understand how they change with changes in the muscle forces. The model included the femur, tibia, patella and all components of cruciate and collateral ligaments, quadriceps, hamstrings and gastrocnemius muscles. Inputs to the model were the muscle forces, estimated by a static optimization approach, the external loads (ground reaction forces and moments) and the knee flexion/extension movement corresponding to natural walking. The remaining rotational and translational movements were obtained as a result of the dynamic equilibrium of forces. The validation of the model was done by comparing our results with literature data. Several simulations were carried out by sequentially removing the forces of the different muscle groups. Deactivation of the quadriceps produced a decrease of tension in the anterior cruciate ligament (ACL) and an increase in the posterior cruciate ligament (PCL). By removing the hamstrings, the tension of ACL increased at the late swing phase, while the PCL force dropped to zero. Specific effects were observed also at the medial and lateral collateral ligaments. The removal of gastrocnemius muscles produced an increase of tension only on PCL and lateral collateral ligaments. These results demonstrate how musculoskeletal models can contribute to knowledge about complex biomechanical systems as the knee joint.

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.

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